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• 1.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Johannes Gutenberg Univ Mainz, Inst Kernphys, Johann Joachim Becher Weg 45, D-55128 Mainz, Germany..
Measurement of the (n)over-right-arrowp -> d pi(0) pi(0) reaction with polarized beam in the region of the d(*)(2380) resonance2016In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, no 5, p. 1-7, article id 147Article in journal (Refereed)

We report on a high-statistics measurement of the most basic double-pionic fusion reaction over the energy region of the d (*)(2380) resonance by use of a polarized deuteron beam and observing the double fusion reaction in the quasifree scattering mode. The measurements were performed with the WASA detector setup at COSY. The data reveal substantial analyzing powers and confirm conclusions about the d(*) resonance obtained from unpolarized measurements. We also confirm the previous unpolarized data obtained under complementary kinematic conditions.

• 2.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Cross section ratio and angular distributions of the reaction p + d -> He-3 + eta at 48.8MeV and 59.8MeV excess energy2014In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 50, no 6, p. 100-Article in journal (Refereed)

We present new data for angular distributions and on the cross section ratio of the p+d -> He-3+eta reaction at excess energies of Q - 48.8MeV and Q - 59.8 MeV. The data have been obtained at the WASA-at-COSY experiment (Forschungszentrum Julich) using a proton beam and a deuterium pellet target. While the shape of obtained angular distributions show only a slow variation with the energy, the new results indicate a distinct and unexpected total cross section fluctuation between Q = 20MeV and Q = 60 MeV, which might indicate the variation of the production mechanism within this energy interval.

• 3.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Backward single-pion production in the pd -> He-3 pi(0)reaction with WASA-at-COSY2018In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 54, no 9, article id 149Article in journal (Refereed)

New data on the production of single neutral pions in the pd -> He-3 pi(0) reaction are presented. For fifteen proton beam momenta between p(p) = 1.60GeV/c and p(p) = 1.74 GeV/c, differential cross sections are determined over a large fraction of the backward hemisphere. Since the only previous systematic measurements of single-pion production at these energies were made in collinear kinematics, the present work constitutes a significant extension of the current knowledge on this reaction. Even this far above the production threshold, significant changes are found in the behaviour of the angular distributions over small intervals in beam momentum.

• 4.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Department of Physics, FI-40014 University of Jyväskylä, Finland. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Department of Physics, FI-40014 University of Jyväskylä, Finland. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Simulations of the fission-product stopping efficiency in IGISOL2015In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 51, no 59, p. 1-7Article in journal (Refereed)

At the Jyväskylä Ion Guide Isotope Separator On-Line (IGISOL) facility, independent fission yields are measured employing the Penning-trap technique. Fission products are produced, e.g. by impinging protons on a uranium target, and are stopped in a gas-filled chamber. The products are collected by a flow of He gas and guided through a mass separator to a Penning trap, where their masses are identified. This work investigates how fission-product properties, such as mass and energy, affect the ion stopping efficiency in the gas cell. The study was performed using the Geant4 toolkit and the SRIM code. The main results show a nearly mass-independent ion stopping with regard to the wide spread of ion masses and energies, with a proper choice of uranium target thickness. Although small variations were observed, in the order of 5%, the results are within the systematic uncertainties of the simulations. To optimize the stopping efficiency while reducing the systematic errors, different experimental parameters were varied; for instance material thicknesses and He gas pressure. Different parameters influence the mass dependence and could alter the mass dependencies in the ion stopping efficiency.

• 5.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Extraction of angular momenta from isomeric yield ratios: Employing TALYS to de-excite primary fission fragments2019In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 55, no 4, article id 61Article in journal (Refereed)

The generation of angular momentum in fission is difficult to model, in particular at higher excitation energies where data are scarce. Isomeric yield ratios (IYR) play an important role in deducing angular momentum properties of fission fragments (FF), albeit this requires some assumptions and simplifications. To estimate FF angular momentum, fission codes can be used to calculate IYRs and compare them to experimental data. Such measurements have systematically been performed at the IGISOL facility using novel experimental techniques. In conjunction, a new method has been developed to infer the angular momentum of the primary FF using the nuclear reaction code TALYS. In this work, we evaluate this new method by comparing our TALYS calculations with values found in the literature and with results from the GEF fission code, for a few well-studied reactions. The overall results show a consistent performance of TALYS and GEF, as well as of many reported literature values. However, some deviations were found, possibly pinpointing the need to re-examine some of the reported literature values. A sensitivity analysis was also performed, in which the role of excitation energy, neutron emission, discrete level structure and level density models were studied. Finally, the role of multiple chance fission, of relevance for the reactions studied at IGISOL, is discussed. Some literature data for this reaction were also re-analyzed using TALYS, revealing significant differences.

• 6. Assié, M.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Neutron correlations in 6He viewed through nuclear break-up2009In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 42, no 3, p. 441-446Article in journal (Refereed)

The nuclear break-up of He-6 on a Pb-208 target was studied at 20 A MeV using a secondary beam of He-6 produced by the SPIRAL facility at GANIL. alpha-particles were detected in coincidence with two neutrons with a large angular coverage and the reaction mechanism was identified. From the distribution of the relative angles between the two neutrons the correlation function was extracted. It shows a strong correlation at small relative angles attributed to the contribution of the di-neutron configuration of He-6.

• 7. Barucca, G.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Precision resonance energy scans with the PANDA experiment at FAIR: Sensitivity study for width and line shape measurements of the X(3872)2019In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 55, no 3, article id 42Article in journal (Refereed)

This paper summarises a comprehensive Monte Carlo simulation study for precision resonance energy scan measurements. Apart from the proof of principle for natural width and line shape measurements of very narrow resonances with PANDA, the achievable sensitivities are quantified for the concrete example of the charmonium-like X(3872) state discussed to be exotic, and for a larger parameter space of various assumed signal cross-sections, input widths and luminosity combinations. PANDA is the only experiment that will be able to perform precision resonance energy scans of such narrow states with quantum numbers of spin and parities that differ from JPC=1--.

• 8.
INFN, Sez Bari, Bari, Italy.
European Org Nucl Res CERN, Geneva, Switzerland. Natl Tech Univ Athens, Athens, Greece. Univ Ioannina, Ioannina, Greece. CEA, DEN, DER SPRC LEPh, F-13108 Cadarache, St Paul Lez Dur, France. INFN Lab Nazl Sud, Catania, Italy. European Org Nucl Res CERN, Geneva, Switzerland. Univ Manchester, Manchester, Lancs, England. Univ Paris Saclay, Irfu, CEA Saclay, Gif Sur Yvette, France. European Org Nucl Res CERN, Geneva, Switzerland. INFN Lab Nazl Sud, Catania, Italy. Ist Nazl Astrofis INAF, Osservatorio Astron Teramo, Teramo, Italy;INFN, Sez Perugia, Perugia, Italy. INFN Lab Nazl Sud, Catania, Italy. European Commiss, Joint Res Ctr, Directorate G, Retieseweg 111, B-2440 Geel, Belgium. European Commiss, Joint Res Ctr, Directorate G, Retieseweg 111, B-2440 Geel, Belgium. Univ Bologna, Dipartimento Fis & Astron, Bologna, Italy;INFN, Sez Bologna, Bologna, Italy. Univ Bologna, Dipartimento Fis & Astron, Bologna, Italy;INFN, Sez Bologna, Bologna, Italy. Ctr Invest Energet Medioambientales & Tecnol CIEM, Madrid, Spain. Horia Hulubei Natl Inst Phys & Nucl Engn IFIN HH, Bucharest, Romania. European Commiss, Joint Res Ctr, Directorate G, Retieseweg 111, B-2440 Geel, Belgium. PTB, Bundesallee 100, D-38116 Braunschweig, Germany. PTB, Bundesallee 100, D-38116 Braunschweig, Germany. Univ Seville, Seville, Spain. European Commiss, Joint Res Ctr, Directorate G, Retieseweg 111, B-2440 Geel, Belgium. Univ Manchester, Manchester, Lancs, England. Univ Manchester, Manchester, Lancs, England. Natl Tech Univ Athens, Athens, Greece. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. IPN, IN2P3, CNRS, Orsay, France. European Commiss, Joint Res Ctr, Directorate G, Retieseweg 111, B-2440 Geel, Belgium. INFN, Sez Bologna, Bologna, Italy. INFN, Sez Perugia, Perugia, Italy;GSSI, Laquila, Italy. Univ Manchester, Manchester, Lancs, England. Univ Zagreb, Fac Sci, Dept Phys, Zagreb, Croatia.
The fission experimental programme at the CERN n_TOF facility: status and perspectives2020In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 56, no 2Article, review/survey (Refereed)

Neutron-induced fission reactions play a crucial role in a variety of fields of fundamental and applied nuclear science. In basic nuclear physics they provide important information on properties of nuclear matter, while in nuclear technology they are at the basis of present and future reactor designs. Finally, there is a renewed interest in fission reactions in nuclear astrophysics due to the multi-messenger observation of neutron star mergers and the important role played by fission recycling in r-process nucleosynthesis. Although studied for several decades, many fundamental questions still remain on fission reactions, while modern applications and the development of more reliable nuclear models require high-accuracy and consistent experimental data on fission cross sections and other fission observables. To address these needs, an extensive fission research programme has been carried out at the n_TOF neutron time-of-flight facility at CERN during the last 18 years, taking advantage of the high energy resolution, high luminosity and wide energy range of the neutron beam, as well as of the detection and data acquisition systems designed for this purpose. While long-lived isotopes are studied on the 185 m long flight-path, the recent construction of a second experimental area at a distance of about 19 m has opened the way to challenging measurements of short-lived actinides. This article provides an overview of the n_TOF experimental programme on neutron-induced fission reactions along with the main characteristics of the facility, the various detection systems and data analysis techniques used. The most important results on several major and minor actinides obtained so far and the future perspectives of fission measurements at n_TOF are presented and discussed.

• 9. DiJulio, D. D.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Electromagnetic properties of vibrational bands in Er-1702011In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 47, no 2, p. 25-Article in journal (Refereed)

Excited states of the nucleus Er-170 have been studied by Coulomb excitation using the GASP gamma-ray detector system at the Laboratori Nazionali di Legnaro. The ground-state band along with a low-lying K-pi = 0(+) band and gamma-vibrational band were populated during the experiment. Based on the measured gamma-ray yields, a set of interband and intraband matrix elements has been extracted using the Coulomb excitation code GOSIA. The resulting E2 matrix elements are compared to collective model predictions.

• 10. Erni, W.
Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Technical design report for the PANDA (AntiProton Annihilations at Darmstadt) Straw Tube Tracker2013In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 49, no 2, p. 25-Article in journal (Refereed)

This document describes the technical layout and the expected performance of the Straw Tube Tracker (STT), the main tracking detector of the PANDA target spectrometer. The STT encloses a Micro-Vertex-Detector (MVD) for the inner tracking and is followed in beam direction by a set of GEM stations. The tasks of the STT are the measurement of the particle momentum from the reconstructed trajectory and the measurement of the specific energy loss for a particle identification. Dedicated simulations with full analysis studies of certain proton-antiproton reactions, identified as being benchmark tests for the whole PANDA scientific program, have been performed to test the STT layout and performance. The results are presented, and the time lines to construct the STT are described.

• 11.
Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden;Istanbul Univ, Fac Sci, Dept Phys, TR-34134 Istanbul, Turkey.
Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden. Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden. Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden;Univ Liverpool, Dept Phys, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England. Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden;Univ Helsinki, Dept Chem, POB 3, FIN-00014 Helsinki, Finland. MTA Atomki, H-4001 Debrecen, Hungary. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England. CEA DSM CNRS IN2P3, GANIL, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France. MTA Atomki, H-4001 Debrecen, Hungary. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England. UGC DAE Consortium Sci Res, Kolkata Ctr, Kolkata 700098, India. UGC DAE Consortium Sci Res, Kolkata Ctr, Kolkata 700098, India. Istanbul Univ, Fac Sci, Dept Phys, TR-34134 Istanbul, Turkey. Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England. MTA Atomki, H-4001 Debrecen, Hungary;Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden. Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden. Univ Padua, Dipartimento Fis & Astron, Padua, Italy. CEA DSM CNRS IN2P3, GANIL, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France. Univ York, Dept Phys, York YO10 5DD, N Yorkshire, England. MTA Atomki, H-4001 Debrecen, Hungary. Nigde Omer Halisdemir Univ, Sci & Art Fac, Dept Phys, TR-51200 Nigde, Turkey. Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain. Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden. Univ Paris Saclay, CNRS IN2P3, Ctr Sci Nucl & Sci Mat, F-91405 Orsay, France. Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain. Osaka Univ, Nucl Phys Res Ctr, Osaka, Japan. Royal Inst Technol KTH, Dept Phys, SE-10691 Stockholm, Sweden. CEA DSM CNRS IN2P3, GANIL, Bd Henri Becquerel,BP 55027, F-14076 Caen 5, France. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Univ Warsaw, Heavy Ion Lab, Pasteura 5A, PL-02093 Warsaw, Poland. Univ Paris Saclay, CNRS IN2P3, Ctr Sci Nucl & Sci Mat, F-91405 Orsay, France. Univ Padua, Dipartimento Fis & Astron, Padua, Italy. Univ Jyvaskyla, Dept Phys, FI-40014 Jyvaskyla, Finland. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. MTA Atomki, H-4001 Debrecen, Hungary. Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy. Tsinghua Univ, Dept Phys, Beijing 100084, Peoples R China.
M1 And E2 Transition Rates From Core-Excited States In Semi-Magic Ru-942018In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 54, no 9, article id 145Article in journal (Refereed)

Lifetimes of high-spin states have been measured in the semi-magic (N = 50) nucleus Ru-94. Excited states in Ru-94 were populated in the Ni-58(Ca-40, 4p)Ru-94* fusion-evaporation reaction at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from gamma-rays emitted while the residual nuclei were slowing down in a thick 6 mg/cm(2) metallic Ni-58 target. In total eight excited-state lifetimes in the angular momentum range I = (13-20)h have been measured, five of which were determined for the first time. The corresponding B(M1) and B(E2) reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations.

• 12.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Entanglement in joint Lambda(Lambda)over-bar decay2015In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 51, no 7, article id 74Article in journal (Refereed)

We investigate the joint decay in the reaction . This reaction may provide information on the electromagnetic form factors of the Lambda baryon, in the time-like region. We present a conventional diagram-based calculation where production and decay steps are coherent and summations over final-state proton and anti-proton spins are performed. The resulting cross-section distribution is explicitly covariant as it is expressed in scalar products of the four-momentum vectors of the participating particles. We compare this calculation with that of the folding method which we extend and make explicitly covariant. In the folding method production and decay distributions, not amplitudes, are folded together. Of particular importance is then a correct counting of the number of possible intermediate-hyperon-spin states.

• 13.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Polarization observables in the e+e- ->(Lambda)over-bar Lambda reaction2016In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, no 5, article id 141Article in journal (Refereed)

Cross-section, vector-polarization, and tensor-polarization distributions are calculated for the reactions e(+)e(-) -> (p) over barp and e(+)e(-) ->(Lambda) over bar Lambda . Each reaction requires six characteristic functions that are bilinear in the, possibly complex, electromagnetic Form factors, denoted G(E)(P-2) and G(M) (P-2), of p and A. For the hyperon reaction also the joint-decay distributions of A and A are calculated. Their knowledge allows a complete determination of the hyperon electromagnetic form factors, without measuring hyperon spins. We explain how this is done in practice. For some tensor-polarization components our results are in conflict with previously repeatedly published distributions.

• 14.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics, Nuclear Physics. Departmen t of Physics & Astronom y, UCL, London WC1E 6BT, UK.
Two-pion production in deuteron-deuteron collisions at low energies2006In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 28, no 2, p. 245-249Article in journal (Refereed)

The cross section for the dd->4Hepipi reaction is estimated near threshold in a two-step model where a pion created in the first step produces a second pion in a subsequent interaction.

• 15.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Jefferson Lab, 12000 Jefferson Ave, Newport News, VA 23606 USA..
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
The electromagnetic Sigma-to-Lambda hyperon transition form factors at low energies2017In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 53, no 6, article id 117Article in journal (Refereed)

Using dispersion theory the low-energy electromagnetic form factors for the transition of a Sigma to a Lambda hyperon are related to the pion vector form factor. The additionally required input, i.e. the two-pion-Sigma-Lambda amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the baryons from the octet and optionally from the decuplet. Pion rescattering is again taken into account by dispersion theory. It turns out that the inclusion of decuplet baryons is not an option but a necessity to obtain reasonable results. The electric transition form factor remains very small in the whole low-energy region. The magnetic transition form factor depends strongly on one not very well determined low-energy constant of the NLO Lagrangian. One obtains reasonable predictive power if this low-energy constant is determined from a measurement of the magnetic transition radius. Such a measurement can be performed at the future Facility for Antiproton and Ion Research (FAIR).

• 16.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
The relativistic chiral Lagrangian for decuplet and octet baryons at next-to-leading order2018In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 54, no 6, article id 103Article in journal (Refereed)

A complete and minimal relativistic Lagrangian is constructed at next-to-leading order for SU(3) chiral perturbation theory in the presence of baryon octet and baryon decuplet states. The Lagrangian has 13 terms for the pure decuplet sector, 6 terms for the transition sector from baryon octet to decuplet and (as already known from the literature) 16 terms for the pure octet sector. The minimal field content of 25 of these terms is meson-baryon four-point interactions. 3 terms give rise to the mass splitting for baryon octet and decuplet states, respectively. 2 terms give rise to overall mass shifts. 4 terms provide anomalous magnetic moments and a decuplet-to-octet magnetic transition moment. 1 term leads to an axial vector transition moment. It is shown that meson-baryon three-point coupling constants come in at leading order whereas no additional one appears in the minimal Lagrangian at next-to-leading order. Those low-energy constants that give rise to mass splitting and magnetic moments, respectively, are determined. Predictions are provided for radiative decays of decuplet to octet baryons.

• 17. Hüyük, Tayfun
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA2016In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, no 3, article id 55Article in journal (Refereed)

The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large $\gamma$ -ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23l and it is filled with the EJ301 liquid scintillator, that presents good neutron- $\gamma$ discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the 58Ni + 56Fe reaction measured with the Neutron Wall detector array.

• 18.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. European Commission, Joint Research Centre, Directorate G, Geel, Belgium . European Commission, Joint Research Centre, Directorate G, Geel, Belgium . Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
The impact of neutron emission on correlated fission data from the 2E-2v method2018In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 54, article id 114Article in journal (Refereed)

The double-energy double-velocity (2E-2v) method allows assessing fission-fragment mass yields prior to and after prompt neutron emission with high resolution. It is, therefore, considered as a complementary technique to assess average prompt neutron multiplicity as a function of fragment properties. We have studied the intrinsic features of the 2E-2v method by means of event-wise generated fission-fragment data and found short-comings in the method itself as well as in some common practices of application. We find that the 2E-2v method leads to large deviations in the correlation between the prompt neutron multiplicity and pre-neutron mass, which deforms and exaggerates the so-called “sawtooth” shape of nubar(A). We have identified the treatment of prompt neutron emission from the fragments as the origin of the problem. The intrinsic nature of this deficiency risks to render 2E-2v experiments less interesting. We suggest a method to correct 2E-2v data that can even be applied on existing measurements.

• 19.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Simulated production rates of exotic nuclei from the ion guide for neutron-induced fission at IGISOL2017In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 53, no 12, article id 243Article in journal (Refereed)

An investigation of the stopping efficiency of fission products, in the new ion guide designed for ion production through neutron-induced fission at IGISOL in Jyväskylä, Finland, has been conducted. Our simulations take into account the new neutron converter, enabling measurements of neutron-induced fission yields, and thereby provide estimates of the obtained yields as a function of primary proton beam current. Different geometries, targets, and pressures, as well as models for the effective charge of the stopped ions were tested, and optimisations to the setup for higher yields are suggested. The predicted number of ions stopped in the gas lets us estimate the survival probability of the ions reaching the downstream measurements stations.

• 20.
Natl Tech Univ Athens, Dept Phys, Athens 15780, Greece.
Univ Ioannina, Dept Phys, GR-45110 Ioannina, Greece. Natl Tech Univ Athens, Dept Phys, Athens 15780, Greece. Natl Tech Univ Athens, Dept Phys, Athens 15780, Greece. Natl Tech Univ Athens, Dept Phys, Athens 15780, Greece. Natl Tech Univ Athens, Dept Phys, Athens 15780, Greece. Univ West Att, Dept Naval Architecture, Athens 12210, Greece. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. NCSR Demokritos, Inst Nucl & Particle Phys, Tandem Accelerator Lab, Aghia Paraskevi 15310, Greece. NCSR Demokritos, Inst Nucl & Particle Phys, Tandem Accelerator Lab, Aghia Paraskevi 15310, Greece. NCSR Demokritos, Inst Nucl & Particle Phys, Tandem Accelerator Lab, Aghia Paraskevi 15310, Greece. NCSR Demokritos, Inst Nucl & Radiol Sci, Energy Technol & Safety, Aghia Paraskevi 15310, Greece.
Determination of the Ir-193(n, 2n) reaction cross section and correction methodology for the Ir-191(n, gamma) contamination2019In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 55, no 10, article id 187Article in journal (Refereed)

The cross section of the Ir-193(n, 2n)Ir-192 reaction has been determined by means of the activation technique, relative to the Al-27(n, alpha) and Au-197(n, 2n) reference reactions cross sections, at neutron beam energies ranging from 10 to 21 MeV. The quasi-monoenergetic neutron beams were produced at the 5.5 MV Tandem T11/25 Accelerator Laboratory of NCSR "Demokritos" via the H-2(d, n) and H-3(d, n) reactions. The induced gamma-ray activity of the irradiated target and reference foils was measured with high resolution HPGe detectors. In order to correct for the contribution of the Ir-191(n, gamma)Ir-192 reaction, which is open to low energy parasitic neutrons, a recently developed analysis method was implemented and it is presented in great detail. Furthermore, cross section theoretical calculations were carried out using the EMPIRE and TALYS codes over a wide energy range.

• 21.
Institute of Experimental Physics, Warsaw University.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
On the unusual properties of the 282 keV state in 135Sb2007In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 32, no 1, p. 25-29Article in journal (Refereed)

Recently the first excited state in 135Sb has been observed at the unexpectedly low excitation energy of only 282keV and interpreted as mainly d 5/2 proton coupled to the 134Sn core. Based on theoretical considerations it was suggested that its low excitation energy is related to a relative shift of the proton d 5/2 and g 7/2 orbits induced by the neutron excess. We have measured the lifetime of the 282keV state by the advanced time-delayed βγγ(t) method. The measured half-life, T 1/2 = 6.1(4)ns, yields exceptionally low limits of B(M1;5/21 +→7/21 +)≤3.0×10-4 μ 2 N and B(E2;5/21 +→7/21 +)≤54e 2 fm 4. These strongly hindered M1 and slow E2 transition rates are similar to those for the transition de-populating the first excited state at 405keV in 211Bi. Results of shell model calculations with realistic interactions are presented. The M1 decay rate was found to be extremely sensistive both to the wave function and to the M1 effective operator.

• 22.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
The nucleon as a test case to calculate vector-isovector form factors at low energies2018In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 54, no 1, article id 1Article in journal (Refereed)

Extending a recent suggestion for hyperon form factors to the nucleon case, dispersion theory is used to relate the low-energy vector-isovector form factors of the nucleon to the pion vector form factor. The additionally required input, i.e. the pion-nucleon scattering amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the nucleons and optionally the Delta baryons. Two methods to include pion rescattering are compared: a) solving the Muskhelishvili-OmnSs (MO) equation and b) using an N/D approach. It turns out that the results differ strongly from each other. Furthermore the results are compared to a fully dispersive calculation of the (subthreshold) pion-nucleon amplitudes based on Roy-Steiner (RS) equations. In full agreement with the findings from the hyperon sector it turns out that the inclusion of Delta baryons is not an option but a necessity to obtain reasonable results. The magnetic isovector form factor depends strongly on a low-energy constant of the NLO Lagrangian. If it is adjusted such that the corresponding magnetic radius is reproduced, then the results for the corresponding pion-nucleon scattering amplitude (based on the MO equation) agree very well with the RS results. Also in the electric sector the Delta degrees of freedom are needed to obtain the correct order of magnitude for the isovector charge and the corresponding electric radius. Yet quantitative agreement is not achieved. If the subtraction constant that appears in the solution of the MO equation is not taken from nucleon+Delta chiral perturbation theory but adjusted such that the electric radius is reproduced, then one obtains also in this sector a pion-nucleon scattering amplitude that agrees well with the RS results.

• 23.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Natl Ctr Nucl Res, BP1,Hoza 69, PL-00681 Warsaw, Poland..
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Natl Ctr Nucl Res, BP1,Hoza 69, PL-00681 Warsaw, Poland.. Charles Univ Prague, Dept Nucl Phys, Holesovickach 2, CR-18000 Prague 8, Czech Republic.. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Natl Ctr Nucl Res, BP1,Hoza 69, PL-00681 Warsaw, Poland.;Univ Warsaw, Fac Phys, Pasteura 5, PL-02093 Warsaw, Poland.. Univ Oslo, Dept Chem, POB 1033, N-0315 Oslo, Norway.. CSIC, Inst Estruct Mat, Serrano 119, E-28006 Madrid, Spain.. Univ Manchester, Schuster Lab, Manchester M13 9PL, Lancs, England.. Univ Oslo, Dept Chem, POB 1033, N-0315 Oslo, Norway.. Univ Warsaw, Fac Phys, Pasteura 5, PL-02093 Warsaw, Poland.. Univ Valencia, CSIC, Inst Fis Corpuscular, E-46100 Burjassot, Spain.. Univ Valencia, CSIC, Inst Fis Corpuscular, E-46100 Burjassot, Spain.. Univ Liverpool, Oliver Lodge Lab, Liverpool L69 7ZE, Merseyside, England.;Univ West Scotland, Sch Engn & Comp, Paisley PA1 2BE, Renfrew, Scotland.. Univ Oslo, Dept Chem, POB 1033, N-0315 Oslo, Norway.. Univ Valencia, CSIC, Inst Fis Corpuscular, E-46100 Burjassot, Spain.. CSIC, Inst Estruct Mat, Serrano 119, E-28006 Madrid, Spain.;CERN, Div PPE, CH-1211 Geneva 23, Switzerland.. Univ Bergen, Dept Phys, N-5007 Bergen, Norway..
On the enhanced E1 transitions in the K=3/2 parity doublet band in Ra-2232016In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, no 6, article id 172Article in journal (Refereed)

We have applied the fast timing beta gamma gamma(t) technique to remeasure lifetimes of selected states in Ra-223 populated in the beta(-) decay of Fr-223. T-1/2 = 587(12) ps and 210(13) ps have been obtained for the 3/2(-) and 5/2(-) states at 50.1 and 79.7 keV, that are more accurate than the previous values of 630(70) ps and 166(55) ps, respectively. Our vertical bar D0 vertical bar value of 0.155(10) e.fm obtained for the K = 3/2 configuration together with the available values of vertical bar D0 vertical bar for the K = 1/2 and K = 5/2 parity doublet bands establish the configuration dependence of vertical bar D0 vertical bar at low spins in this nucleus. Results of theoretical calculations performed for Ra-223, using the quasiparticle-phonon model (QPM) with inclusion of the Coriolis coupling, reasonably well reproduce octupole correlations in this nucleus.

• 24. Marganiec, J.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Studies of continuum states in (16) Ne using three-body correlation techniques2015In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 51, no 1, article id 9Article in journal (Refereed)

Two-proton decay of the unbound nucleus Ne-16 , produced in one-neutron knockout from a 500 MeV/u Ne-17 beam, has been studied at GSI. The ground state, at a resonance energy 1.388(15) MeV, ( MeV) above the O-14 +p+p threshold, and two narrow resonances at MeV and 7.57(6) MeV have been investigated. A comparison of the energy difference between the first excited 2(+) state and the 0(+) ground state in Ne-16 with its mirror nucleus C-16 reveals a small Thomas-Ehrman shift (TES) of keV. A trend of the TES for the T = 2 quintet is obtained by completing the known data with a prediction for F-16 obtained from an IMME analysis. The decay mechanisms of the observed three resonances were revealed from an analysis of the energy and angular correlations of the O-14 +p+p decay products. The ground state decay can be considered as a genuine three-body (democratic) mode and the excited states decay sequentially via states in the intermediate nucleus F-15 , the 3.22 MeV state predominantly via the F-15 ground-state resonance, while the 7.57 MeV state decays via the 5/2(+) resonance in F-15 at 2.8 MeV above the O-14 +p+p threshold. Further, from an analysis of angular correlations, the spin-parity of the 7.57 MeV state has been determined as and assigned as the third 2(+) state in Ne-16 based on a comparison with C-16.

• 25.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. INFN - LNF. INFN - LNF; Politecnico di Milano, p.zza L. da Vinci 32. INFN - LNF. INFN - LNF. INFN-LNF; CIEMAT, Complutense 40. Politecnico di Milano, p.zza L. da Vinci 32. Politecnico di Milano, p.zza L. da Vinci 32. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä.
A neutron source for IGISOL-JYFLTRAP: Design and characterisation2017In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 53, no 173Article in journal (Refereed)

A white neutron source based on the Be(p,nx) reaction for fission studies at the IGISOLJYFLTRAP facility has been designed and tested. 30 MeV protons impinge on a 5mm thick water-cooled beryllium disc. The source was designed to produce at least 1012 fast neutrons/s on a secondary fission target, in order to reach competitive production rates of fission products far from the valley of stability.

The Monte Carlo codes MCNPX and FLUKA were used in the design phase to simulate the neutron energy spectra. Two experiments to characterise the neutron field were performed: the first was carried out at The Svedberg Laboratory in Uppsala (SE), using an Extended-Range Bonner Sphere Spectrometer and a liquid scintillator which used the time-of-flight (TOF) method to determine the energy of the neutrons; the second employed Thin-Film Breakdown Counters for the measurement of the TOF, and activation foils, at the IGISOL facility in Jyväskylä (FI). Design considerations and the results of the two characterisation measurements are presented, providing benchmarks for the simulations.

• 26.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä. University of Jyväskylä.
Production of Sn and Sb isotopes in high-energy neutron induced fission of natU2018In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 54, article id 33Article in journal (Refereed)

The first systematic measurement of neutron-induced fission yields has been performed at the upgraded IGISOL-4 facility at the University of Jyvaskyla, Finland. The fission products from high-energy neutron-induced fission of U-nat were stopped in a gas cell filled with helium buffer gas, and were online separated with a dipole magnet. The isobars, with masses in the range A = 128-133, were transported to a tape-implantation station and identified using gamma-spectroscopy. We report here the relative cumulative isotopic yields of tin (Z = 50) and the relative independent isotopic yields of antimony (Z = 51). Isomeric yield ratios were also obtained for five nuclides. The yields of tin show a staggered behaviour around A = 131, not observed in the ENDF/B-VII. 1 evaluation. The yields of antimony also contradict the trend from the evaluation, but are in agreement with a calculation performed using the GEF model that shows the yield increasing with mass in the range A = 128-133.

• 27.
KVI, Groningen.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. ÖAW, Wien, Austria.
Design Studies of the PWO Forward End-cap Calorimeter for PANDA2013In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. A49, p. 138-Article in journal (Refereed)

The PANDA detection system at FAIR, Germany, is designed to study antiproton-proton annihilations, in order to investigate among others the realm of charm-meson states and glueballs, which has still much to reveal. The yet unknown properties of this field are to be unraveled through studying QCD phenomena in the non-perturbative regime. The multipurpose PANDA detector will be capable of tracking, calorimetry, and particle identification, and is foreseen to run at high luminosities providing average reaction rates up to 20 Million interactions/s. The envisaged physics program requires measurements of photons and charged particles with excellent energy, position, and time resolutions. The electromagnetic calorimeter (EMC) will serve as one of the basic components of the detector setup and comprises cooled Lead-Tungstate (PbWO4) crystals. This paper presents the mechanical design of the Forward End-cap calorimeter and analyses the response of this detector component in conjunction with the full EMC and the complete PANDA detector. The simulation studies are focused on the performance of the planned EMC with respect to the energy and spatial resolution of the reconstructed photons. Results of the Monte Carlo simulations, excluding very low-energy photons, have been validated by data obtained from a prototype calorimeter and shown to fulfil the requirements imposed by the PANDA physics program.

• 28. Moskal, P.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Invariant-mass distributions for the pp -> pp eta reaction at Q=10 MeV2010In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 43, no 2, p. 131-136Article in journal (Refereed)

Proton-proton and proton-eta invariant-mass distributions and the total cross-section for the pp -> pp eta reaction have been determined near the threshold at an excess energy of Q = 10 MeV. The experiment has been conducted using the COSY-11 detector setup and the cooler synchrotron COSY. The determined invariant-mass spectra reveal significant enhancements in the region of low proton-proton relative momenta, similarly as observed previously at higher excess energies of Q = 15.5 MeV and Q = 40 MeV.

• 29. Roeder, M.
Uppsala University, The Svedberg Laboratory.
Efficiency determination of resistive plate chambers for fast quasi-monoenergetic neutrons2014In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 50, no 7, article id 112Article in journal (Refereed)

Composite detectors made of stainless-steel converters and multigap resistive plate chambers have been irradiated with quasi-monoenergetic neutrons with a peak energy of 175 MeV. The neutron detection efficiency has been determined using two different methods. The data are in agreement with the output of Monte Carlo simulations. The simulations are then extended to study the response of a hypothetical array made of these detectors to energetic neutrons from a radioactive ion beam experiment.

• 30. Ruchowska, E.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Quenching of the E1 strength in Nd-1492010In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 45, no 1, p. 1-10Article in journal (Refereed)

Lifetime measurements of excited states in Nd-149 have been performed using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 excited states in Nd-149 have been determined for the first time or measured with higher precision. Twelve new gamma-lines and 5 new levels have been introduced into the decay scheme of Pr-149 based on results of the gamma gamma coincidence measurements. Reduced transition probabilities have been determined for 40 gamma-transitions in Nd-149. Configuration assignments for 6 rotational bands in Nd-149 are proposed. Enhanced E1 transitions indicate that the ground-state band and the band built on the 332.9 keV level constitute a pair of the K-pi = 5/2(+/-) parity doublet bands. Potential energy surfaces on the (beta(2),beta(3))-plane have been calculated for the lowest single quasi-particle configurations in Nd-149 using the Strutinski method and the axially deformed Woods-Saxon potential. The predicted occurrence of the octupole-deformed K = 5/2 configuration is in agreement with experiment. Unexpectedly low vertical bar D-0 vertical bar values obtained for the K-pi = 5/2(+/-) parity doublet bands may result from cancellation between the proton and neutron shell correction contributions to vertical bar D-0 vertical bar.

• 31.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Studies of quadrupole collectivity in the γ -soft 106Ru2008In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 35, no 2, p. 159-165Article in journal (Refereed)

Various alternative models were used to describe the structure of Ru-106. For example, the General Collective Model (GCM) predicts shape-coexistence for Ru-106 with a spherical and a triaxial minimum and strongly mixed structures, while in the IBA-2 calculations, where Ru-106 was considered as transitional from vibrational U(5) to gamma -soft O(6) , no need was found to include the shape-coexisting configurations. In order to provide additional constraints on the model interpretations, we have applied the Advanced Time-Delayed (ATD) beta gamma gamma(t) method to measure the level lifetimes of the excited levels in Ru-106 . The new results include the half-lives of T-1/2 = 183(3) ps and 7.5(30)ps for the 2(1)(+) and 2(1)(+) states, respectively.

• 32.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Production of eta and 3 pi mesons in the pd -> (HeX)-He-3 reaction at 1360 and 1450 MeV2010In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 45, no 1, p. 11-21Article in journal (Refereed)

The cross-sections of the pd -> He-3 eta, pd -> He-3 pi(0)pi(0)pi(0) and pd -> He-3 pi(+)pi(-)pi(0) reactions have been measured at the beam kinetic energies T-p = 1360 MeV and T-p = 1450 MeV using the CELSIUS/WASA detector setup. At both energies, the differential cross-section d sigma/d Omega of the eta meson in the pd -> He-3 eta reaction shows a strong forward-backward asymmetry in the CMS. The ratio between the pd -> He-3 pi(+)pi(-)pi(0) and pd -> He-3 pi(0)pi(0)pi(0) cross-sections has been analysed in terms of isospin amplitudes. The reconstructed invariant-mass distributions of the pi pi, He-3 pi and (3)He2 pi systems provide hints on the role of nucleon resonances in the 3 pi production process.

• 33.
Aligarth Muslim Univ, Dept Phys, Aligarh, India..
Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR2016In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 52, no 10, article id 325Article in journal (Refereed)

Simulation results for future measurements of electromagnetic proton form factors at PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel (p) over barp -> e(+)e(-) is studied on the basis of two different but consistent procedures. The suppression of the main background channel, i.e. (p) over barp -> pi(+)pi(-), is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance.

• 34.
Aligarth Muslim Univ, Dept Phys, Aligarh, India..
Experimental access to Transition Distribution Amplitudes with the PANDA experiment at FAIR2015In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 51, no 8, article id 107Article in journal (Refereed)

Baryon-to-meson Transition Distribution Amplitudes (TDAs) encoding valuable new information on hadron structure appear as building blocks in the collinear factorized description for several types of hard exclusive reactions. In this paper, we address the possibility of accessing nucleon-to-pion (pi N) TDAs from (p) over barp -> e(+)e(-)pi(0) reaction with the future PANDA detector at the FAIR facility. At high center-of-mass energy and high invariant mass squared of the lepton pair q(2), the amplitude of the signal channel (p) over barp -> e(+)e(-)pi(0) admits a QCD factorized description in terms of pi N TDAs and nucleon Distribution Amplitudes (DAs) in the forward aid backward kinematic regimes. Assuming the validity of this factorized description, we perform feasibility studies for measuring (p) over barp -> e(+)e(-)pi(0) with the PANDA detector. Detailed simulations on signal reconstruction efficiency as well as on rejection of the most severe background channel, i.e. (p) over barp -> pi(+)pi(-)pi(0) were performed for the center-of-mass energy squared s = 5 GeV2 and s = 10 GeV2, in the kinematic regions 3.0 < q(2) < 4.3 GeV2 and 5 < q(2) < 9 GeV2, respectively, with a neutral pion scattered in the forward or backward cone vertical bar cos theta(pi 0)vertical bar > 0.5 in the proton-antiproton center-of-mass frame. Results of the simulation show that the particle identification capabilities of the PANDA detector will allow to achieve a background rejection factor of 5 . 10(7) (1 . 10(7)) at low (high) q(2) for s = 5 GeV2, and of 1 . 10(8) (6 . 10(6)) at low (high) q(2) for s = 10 GeV2, while keeping the signal reconstruction efficiency at around 40%. At both energies, a clean lepton signal can be reconstructed with the expected statistics corresponding to 2 of integrated luminosity. The cross sections obtained from the simulations are used to show that a test of QCD collinear factorization can be done at the lowest order by measuring scaling laws and angular distributions. The future measurement of the signal channel cross section with PANDA will provide a new test of the perturbative QCD description of a novel class of hard exclusive reactions and will open the possibility of experimentally accessing pi N TDAs.

• 35. Skorodko, T.
Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, The Svedberg Laboratory. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, The Svedberg Laboratory. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
Excitation of the Roper resonance in single- and double-pion production in nucleon-nucleon collisions2008In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 35, no 3, p. 317-319Article in journal (Refereed)

In most investigations the Roper resonance is sensed only very indirectly via complex partial-wave analyses. We find indications for its excitation in the invariant n pi(+) mass spectrum of the pp -> np pi(+) reaction at M approximate to 1360 MeV with a width of approximate to 150 MeV . The values fit very favorably to the most recent phase shift results as well as to the observations at BES. In the near-threshold two-pion production pp -> pp pi(0)pi(0) , where the Roper excitation and its subsequent decays via the routes N* -> Delta pi -> N pi pi and N* -> N sigma are the only dominant processes, we find its direct decay into the N sigma channel to be the by far dominating decay process -in favor of a monopole excitation of the Roper resonance.

• 36. Skorodko, T.
Uppsala University, The Svedberg Laboratory. Uppsala University, The Svedberg Laboratory. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Exclusive measurement of the pp -> nn pi(+)pi(+) reaction at 1.1 GeV2011In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 47, no 9, p. 108-Article in journal (Refereed)

First exclusive data for the pp -> nnp(+)pi(+) reaction have been obtained at CELSIUS with the WASA detector setup at a beam energy of T(p) - 1.1 GeV. Total and differential cross-sections disagree with theoretical calculations, which predict the Delta Delta excitation to be the dominant process at this beam energy. Instead, the data require the excitation of one of the nucleons to a higher-lying Delta state, preferably the Delta(1600)P(33), to be the leading process.

• 37. Sohler, D
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Radiation Sciences.
Spectroscopy of neutron deficient Te-1081998In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 3, no 3, p. 209-211Article in journal (Refereed)

The neutron deficient nucleus 108Te was studied in the 54Fe(58Ni,2p2n) reaction. A detector system consisting of 4 Euroball cluster detectors, a charged-particle detector ball and a 16 element neutron multiplicity filter was used to detect the emitted particles and γ rays. A new, significantly extended level scheme was constructed on the basis of γγ-coincidence relations. Spin values for the states were determined from angular distribution ratios. The experimental results are discussed in terms of the shell model.

• 38.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Electromagnetic transitions in an effective chiral Lagrangian with the eta ' and light vector mesons2012In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 48, no 12, p. 190-Article in journal (Refereed)

We consider the chiral Lagrangian with a nonet of Goldstone bosons and a nonet of light vector mesons. The mixing between the pseudoscalar mesons eta and eta' is taken into account. A novel counting scheme is suggested that is based on hadrogenesis, which conjectures a mass gap in the meson spectrum of QCD in the limit of a large number of colors. Such a mass gap would justify to consider the vector mesons and the eta' meson as light degrees of freedom. The complete leading-order Lagrangian is constructed and discussed. As a first application it is tested against electromagnetic transitions of light vector mesons to pseudoscalar mesons. Our parameters are determined by the experimental data on photon decays of the omega, phi and eta' mesons. In terms of such parameters we predict the corresponding decays into virtual photons with either dielectrons or dimuons in the final state.

• 39.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Reactions with pions and vector mesons in the sector of odd intrinsic parity2013In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 49, no 9, p. 116-Article in journal (Refereed)

TheWess-Zumino-Witten structure is supplemented by a simple vector-meson Lagrangian where the vector mesons are described by antisymmetric tensor fields. With the rho-omega-pi coupling as the only parameter in the sector of odd intrinsic parity, i.e. without additional contact terms, one can achieve a proper description of the decay of an omega-meson into three pions, the single-and double-virtual pion transition form factor and the three-pion production in electron-positron collisions.

• 40. Zielinski, M. J.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear Physics.
Reaction pp -> pp pi pi pi as a background for hadronic decays of the eta ' meson2011In: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 47, no 8, p. 93-Article in journal (Refereed)

Isospin violating hadronic decays of the eta and eta ' mesons into 3 pi mesons are driven by a term in the QCD Lagrangian proportional to the mass difference of the d and u quarks. The source giving large yield of the mesons for such decay studies are pp interactions close to the respective kinematical thresholds. The most important physics background for eta, eta ' -> pi pi pi is coming from direct three-pion production reactions. In case of the eta meson the background for the decays is relatively low (approximate to 10%). The purpose of this article is to provide an estimate of the direct pion production background for the eta ' -> 3 pi decays. Using the inclusive data from the COSY-11 experiment we have extracted the differential cross-section for the pp -> pp-multipion production reactions with the invariant mass of the pions equal to the eta ' meson mass and estimated an upper limit for the signal to background ratio for studies of the eta ' -> pi(+)pi(-)pi(0)decay.

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