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• 1. Abazov, V.M.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Observation of the Doubly Strange b Baryon Omega(-)(b)2008In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 101, no 23, p. 232002-Article in journal (Refereed)

We report the observation of the doubly strange b baryon Omega(-)(b) in the decay channel Omega(-)(b) -> J/psi Omega(-), with J/psi -> mu(+)mu(-) and Omega(-) -> Lambda K- -> (p pi(-))K-, in p (p) over bar collisions at root s = 1.96 TeV. Using approximately 1.3 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8 +/- 4.9(stat) +/- 0.8(syst) Omega(-)(b) signal events at a mass of 6.165 +/- 0.010(stat) +/- 0.013(syst) GeV. The significance of the observed signal is 5.4 sigma, corresponding to a probability of 6.7 x 10(-8) of it arising from a background fluctuation.

• 2. Abdallah, J...
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. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Higgs boson searches in CP-conserving and CP-violating MSSM scenarios with the DELPHI detector2008In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 54, no 1, p. 1-35Article in journal (Refereed)

This paper presents the final interpretation of the results from DELPHI on the searches for Higgs bosons in the minimal supersymmetric extension of the Standard Model (MSSM). A few representative scenarios are considered, that include CP conservation and explicit CP violation in the Higgs sector. The experimental results encompass the searches for neutral Higgs bosons at LEP1 and LEP2 in final states as expected in the MSSM, as well as LEP2 searches for charged Higgs bosons and for neutral Higgs bosons decaying into hadrons independent of the quark flavour. The data reveal no significant excess with respect to background expectations. The results are translated into excluded regions of the parameter space in the various scenarios. In the CP-conserving case, these lead to limits on the masses of the lightest scalar and pseudoscalar Higgs bosons, h and A, and on tan beta. The dependence of these limits on the top quark mass is discussed. Allowing for CP violation reduces the experimental sensitivity to Higgs bosons. It is shown that this effect depends strongly on the values of the parameters responsible for CP violation in the Higgs sector.

• 3. Abdallah, J...
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. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Measurement of the tau lepton polarisation at LEP22008In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 659, no 1-2, p. 65-73Article in journal (Refereed)

A first measurement of the average polarisation P-tau of tau leptons produced in e(+)e(-) annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P-tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV.

• 4. Abdallah, J.,...
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 Nuclear and Particle Physics, High Energy Physics.
Study of b-quark mass effects in multijet topologies with the DELPHIdetector at LEP2008In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 55, no 4, p. 525-538Article in journal (Refereed)

The effect of the heavy b-quark mass on the two, three and four-jet rates isstudied using LEP data collected by the DELPHI experiment at the Z peak in1994 and 1995. The rates of b-quark jets and light quark jets (l = uds) inevents with n = 2, 3, and 4 jets, together with the ratio of two andfour-jet rates of b-quarks with respect to light-quarks, R_n^bl, have beenmeasured with a double-tag technique using the CAMBRIDGE jet-clusteringalgorithm. A comparison between experimental results and theory (matrixelement or Monte Carlo event generators such as PYTHIA, HERWIG and ARIADNE)is done after the hadronisation phase. Using the four-jet observable R_4^bl,a measurement of the b-quark mass using massive leading-order calculationsgives: m_b(M_Z) = 3.76 +/- 0.32 (stat) +/- 0.17 (syst) +/- 0.22 (had) +/-0.90 (theo) GeV/c^2 . This result is compatible with previous three-jetdeterminations at the M_Z energy scale and with low energy mass measurementsevolved to the M_Z scale using QCD Renormalisation Group Equations.

• 5. Abdesselam, A.
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.
The detector control system of the ATLAS SemiConductor Tracker during macro-assembly and integration2008In: Journal of Instrumentation, ISSN 1748-0221, Vol. 3, p. P02007-Article in journal (Refereed)

The ATLAS SemiConductor Tracker (SCT) is one of the largest existing semiconductor detectors. It is situated between the Pixel detector and the Transition Radiation Tracker at one of the four interaction points of the Large Hadron Collider (LHC). During 2006-2007 the detector was lowered into the ATLAS cavern and installed in its final position. For the assembly, integration and commissioning phase, a complete Detector Control System (DCS) was developed to ensure the safe operation of the tracker. This included control of the individual powering of the silicon modules, a bi-phase cooling system and various types of sensors monitoring the SCT environment and the surrounding test enclosure. The DCS software architecture, performance and operational experience will be presented in the view of a validation of the DCS for the final SCT installation and operation phase.

• 6. Arbey, A.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
SUSY constraints from relic density: High sensitivity to pre-BBN expansion rate2008In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 669, no 1, p. 46-51Article in journal (Refereed)

The sensitivity of the lightest supersymmetric particle relic density calculation to the variation of the cosmological expansion rate before nucleosynthesis is discussed. Such a modification of the expansion rate, even extremely modest and with no consequence on the cosmological observations can greatly, enhance the calculated relic density, and therefore change the constraints on the SUSY parameter space drastically. We illustrate this variation in two examples of SUSY models, and show that it is unsafe to use the lower bound of the WMAP limits in order to constrain supersymmetry. We therefore suggest to use only the upper value Omega(DM)h(2) < 0.135. (C) 2008 Elsevier B.V. All rights reserved.

• 7. Bashkanov, M.
Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, The Svedberg Laboratory. 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. 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. 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 Physics and Astronomy, Nuclear and Particle Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, The Svedberg Laboratory. Uppsala University, The Svedberg Laboratory. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics. Uppsala University, The Svedberg Laboratory. 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. 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. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Nuclear and Particle Physics.
Measurement of the slope parameter for the η → 3π0 decay in the pp → ppη reaction2007In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 76, no 4, p. 048201-Article in journal (Refereed)

The CELSIUS-WASA setup is used to measure the 3π0 decay of η mesons produced in pp interactions with beam kinetic energies of 1.36 and 1.45 GeV. The efficiency-corrected Dalitz plot and density distributions for this decay are shown, together with a fit of the quadratic slope parameter α yielding α = −0.026 ± 0.010(stat) ± 0.010(syst). This value is compared to recent experimental results and theoretical predictions.

• 8.
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. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Di-jet production in gamma gamma collisions at LEP22008In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 58, no 4, p. 531-541Article in journal (Refereed)
• 9.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Department of Physics and Astronomy, University of Iowa. Department of Physics, University of Arizona.
High energy neutrinos from charm in astrophysical sources2009In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 79, no 5, p. 053006-Article in journal (Refereed)

Charm production gives rise to a flux of very high energy neutrinos from astrophysical sources with jets driven by central engines, such as gamma ray bursts or supernovae with jets. The neutrino flux from semileptonic decays of charmed mesons is subject to much less hadronic and radiative cooling than the conventional flux from pion and kaon decays and therefore has a dominant contribution at higher energies, which is of relevance to future ultrahigh energy neutrino experiments.

• 10.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Charged Higgs effects on top spin correlations2009In: Proceedings of Science, ISSN 1824-8039, Vol. CHARGED2008, no 024Article in journal (Refereed)
• 11.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Phenomenology of Charged Higgs Bosons and B-meson Decays2009Doctoral thesis, comprehensive summary (Other academic)

For more than 30 years the Standard Model has been the theoretical foundation for particle physics. The theory has been veriﬁed successfully by experimental tests. Its biggest shortcoming is the non-discovery of the Higgs boson,responsible for giving the other particles masses. Despite its success there are hints that the Standard Model is not the complete theory and many extensions of it, such as supersymmetry, have been proposed.

Extended theories often predict the existence of a charged Higgs boson and its detection will be a clear sign of physics beyond the Standard Model. The main focus in this thesis is on various phenomenological aspects of the charged Higgs boson. For favorable mass and couplings direct detection is shown to be possible at the Large Hadron Collider in production with an associated W boson. It is also shown how a light charged Higgs can have measurable effects on spin correlations in decays of pair-produced top quarks. The charged Higgs boson can also be seen indirectly, in for example B-meson decays, which can be used to put constraints on its mass and fermion couplings. Exclusion limits in two supersymmetric models are given together with a comparison with the discovery potentials for the LHC experiments. A tool for calculating properties, such as masses and decays, of both charged and neutral Higgs bosons in the Two-Higgs-Doublet Model is also presented.

B-meson decays can also be used to test aspects of the strong interaction. Part of this thesis deals with improving and applying phenomenological models to B-meson decays. Although these models are not derived from ﬁrst principles, their success shows that they capture important features of non-perturbative strong interactions.

1. Associated charged Higgs and W boson production in the MSSM at the CERN Large Hadron Collider
Open this publication in new window or tab >>Associated charged Higgs and W boson production in the MSSM at the CERN Large Hadron Collider
2008 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 53, no 2, p. 267-280Article in journal (Refereed) Published
##### Abstract [en]

We investigate the viability of observing charged Higgs bosons () produced in association with bosons at the CERN large hadron collider, using the leptonic decay and hadronic decay, within different scenarios of the minimal supersymmetric standard model (MSSM) with both real and complex parameters. Performing a parton level study we show how the irreducible standard model background from jets can be controlled by applying appropriate cuts and find that the size of a possible signal depends on the cuts needed to suppress QCD backgrounds and misidentifications. In the standard maximal mixing scenario of the MSSM we find a viable signal for large and intermediate masses () when using softer cuts (, 50 GeV), whereas for harder cuts (, 100 GeV) we only find a viable signal for very large (). We have also investigated a special class of MSSM scenarios with large mass splittings among the heavy Higgs bosons where the cross-section can be resonantly enhanced by factors up to one hundred, with a strong dependence on the -violating phases. Even so we find that the signal after cuts remains small except for small masses () when using the softer cuts. Finally, in all the scenarios we have investigated we have only found small -asymmetries.

##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-98098 (URN)10.1140/epjc/s10052-007-0453-x (DOI)000252299200007 ()
Available from: 2009-02-11 Created: 2009-02-11 Last updated: 2017-12-13Bibliographically approved
2. PYBBWH: A program for associated charged Higgs and W boson production
Open this publication in new window or tab >>PYBBWH: A program for associated charged Higgs and W boson production
##### Abstract [en]

The Monte Carlo program, PYBBWH, is an implementation of the associated production of a charged Higgs and a W boson from $b\bar b$ fusion in a general Two-Higgs-Doublet model for both CP-conserving and CP-violating couplings.It is implemented as a external process to Pythia 6.The code can be downloaded from http://www.isv.uu.se/thep/MC/pybbwh.

##### Identifiers
urn:nbn:se:uu:diva-98099 (URN)
Available from: 2009-02-25 Created: 2009-02-11 Last updated: 2010-01-14Bibliographically approved
3. New angles on top quark decay to a charged Higgs
Open this publication in new window or tab >>New angles on top quark decay to a charged Higgs
2009 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 01, no 1, p. 024-Article in journal (Refereed) Published
##### Abstract [en]

To properly discover a charged Higgs Boson (H±) requires its spin and couplings to be determined. We investigate how to utilize t spin correlations to analyze the H± couplings in the decay tbH+bτ+ντ. Within the framework of a general Two-Higgs-Doublet Model, we obtain results on the spin analyzing coefficients for this decay and study in detail its spin phenomenology, focusing on the limits of large and small values for tan β. Using a Monte Carlo approach to simulate full hadron-level events, we evaluate systematically how the H± → τ±ντ decay mode can be used for spin analysis. The most promising observables are obtained from azimuthal angle correlations in the transverse rest frames of t(). This method is particularly useful for determining the coupling structure of H± in the large tan β limit, where differences from the SM are most significant.

##### Keywords
Beyond Standard Model, Higgs Physics, Spin and Polarization Effects, Hadronic Colliders
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-98100 (URN)10.1088/1126-6708/2008/01/024 (DOI)000252983400053 ()
Available from: 2009-02-11 Created: 2009-02-11 Last updated: 2017-12-13Bibliographically approved
4. Charged Higgs effects on top spin correlations
Open this publication in new window or tab >>Charged Higgs effects on top spin correlations
2009 (English)In: Proceedings of Science, ISSN 1824-8039, Vol. CHARGED2008, no 024Article in journal (Refereed) Published
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-98101 (URN)
Available from: 2009-02-11 Created: 2009-02-11 Last updated: 2009-06-17Bibliographically approved
5. Charged Higgs bosons in minimal supersymmetry: updated constraints and experimental prospects
Open this publication in new window or tab >>Charged Higgs bosons in minimal supersymmetry: updated constraints and experimental prospects
2008 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 11, no 035Article in journal (Refereed) Published
##### Abstract [en]

We discuss the phenomenology of charged Higgs bosons in the MSSM with minimal flavor violation. In addition to the constrained MSSM (CMSSM) with universal soft supersymmetry breaking mass parameters at the GUT scale, we explore non-universal Higgs mass models (NUHM) where this universality condition is relaxed. To identify the allowed parameter space regions, we apply constraints from direct searches, low energy observables, and cosmology. We find that values of the charged Higgs mass as low as mH+ 135 GeV can be accommodated in the NUHM models, but that several flavor physics observables disfavor large H+ contributions, associated with high tan β, quite independently of MSSM scenario. We confront the constrained scenarios with the discovery potentials reported by ATLAS and CMS, and find that the current exclusion by indirect constraints is similar to the expected LHC discovery reach with 30 fb−1 of data. Finally, we evaluate the sensitivity of the presented discovery potential to the choice of MSSM benchmark scenario. This sensitivity is found to be higher in the case of a light (mH+ < mt) charged Higgs.

##### Keywords
Supersymmetric Standard Model, Higgs Physics, Hadronic Colliders
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-98102 (URN)10.1088/1126-6708/2008/11/035 (DOI)000261315100035 ()
Available from: 2009-02-11 Created: 2009-02-11 Last updated: 2017-12-13Bibliographically approved
6. Color rearrangements in B-meson decays
Open this publication in new window or tab >>Color rearrangements in B-meson decays
2009 (English)In: Physical Review D, ISSN 1550-7998, E-ISSN 1550-2368, Vol. 79, no 1, p. 014011-Article in journal (Refereed) Published
##### Abstract [en]

Wepresent a new model, based on color rearrangements, which atthe same time can describe both hidden and open charmproduction in B-meson decays. The model is successfully compared toboth inclusive decays, such as B-->J/psiX and B-->DsX, as wellas exclusive ones, such as B-->J/psiK(*) and B-->D(*)D(*)K. It alsogives a good description of the momentum distribution of directJ/psi's, especially in the low-momentum region, which earlier has beenclaimed as a possible signal for new exotic states.

##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-98103 (URN)10.1103/PhysRevD.79.014011 (DOI)000262979700036 ()
Available from: 2009-02-11 Created: 2009-02-11 Last updated: 2017-12-13Bibliographically approved
7. 2HDMC - two-Higgs-doublet model calculator
Open this publication in new window or tab >>2HDMC - two-Higgs-doublet model calculator
2010 (English)In: Computer Physics Communications, ISSN 0010-4655, E-ISSN 1879-2944, Vol. 181, no 1, p. 189-205Article in journal (Refereed) Published
##### Abstract [en]

We describe the public C++ code 2HDMC which can be used to perform calculations in a general, CP-conserving, two-Higgs-doublet model (2HDM). The program features simple conversion between different parametrizations of the 2HDM potential, a flexible Yukawa sector specification with choices of different Z_2-symmetries or more general couplings, a decay library including all two-body - and some three-body - decay modes for the Higgs bosons, and the possibility to calculate observables of interest for constraining the 2HDM parameter space, as well as theoretical constraints from positivity and unitarity. The latest version of the 2HDMC code and full documentation is available from: http://www.isv.uu.se/thep/MC/2HDMC.

##### Keywords
Higgs physics, Two-Higgs-doublet model
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-111157 (URN)10.1016/j.cpc.2009.09.011 (DOI)000273168600022 ()
##### Note
Erratum in: Computer Physics Communications, 2010, vol. 181, issue 5, p. 985, doi: 10.1016/j.cpc.2009.12.026 Available from: 2009-12-04 Created: 2009-12-04 Last updated: 2017-12-12Bibliographically approved
• 12.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
PYBBWH: A program for associated charged Higgs and W boson productionManuscript (Other academic)

The Monte Carlo program, PYBBWH, is an implementation of the associated production of a charged Higgs and a W boson from $b\bar b$ fusion in a general Two-Higgs-Doublet model for both CP-conserving and CP-violating couplings.It is implemented as a external process to Pythia 6.The code can be downloaded from http://www.isv.uu.se/thep/MC/pybbwh.

• 13.
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.
New angles on top quark decay to a charged Higgs2009In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, Vol. 01, no 1, p. 024-Article in journal (Refereed)

To properly discover a charged Higgs Boson (H±) requires its spin and couplings to be determined. We investigate how to utilize t spin correlations to analyze the H± couplings in the decay tbH+bτ+ντ. Within the framework of a general Two-Higgs-Doublet Model, we obtain results on the spin analyzing coefficients for this decay and study in detail its spin phenomenology, focusing on the limits of large and small values for tan β. Using a Monte Carlo approach to simulate full hadron-level events, we evaluate systematically how the H± → τ±ντ decay mode can be used for spin analysis. The most promising observables are obtained from azimuthal angle correlations in the transverse rest frames of t(). This method is particularly useful for determining the coupling structure of H± in the large tan β limit, where differences from the SM are most significant.

• 14.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Nuclear and Particle Physics, High Energy Physics.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Nuclear and Particle Physics, High Energy Physics.
2HDMC: Physics and ManualManuscript (Other academic)
• 15.
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 Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science.
Heavy-Ion Induced Desorption of a TiZrV Coated Vacuum Chamber Bombarded with 5 MeV/u Ar8+ beam at grazing incidence2009In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 27, no 1, p. 139-144Article in journal (Refereed)

TiZrV nonevaporable getter (NEG) coated vacuum chambers is a new vacuum technology which is already used in many particle accelerators worldwide. This coating is also of interest for heavy-ion accelerator vacuum chambers. Heavy-ion desorption yields from an activated as well as a CO saturated NEG coated tube have been measured with 5 MeV/u Ar8+ beam. The sticking probability of the NEG film was obtained by using the partial pressure ratios on two sides of the NEG coated tube. These ratios were compared to results of modeling of the experimental setup with test particle Monte Carlo and angular coefficient methods. The   partial pressures inside the saturated NEG coated tube bombarded with heavy ions were up to 20 times larger than those inside the activated one. However, the partial pressure of methane remained the same. The value of the total desorption yield from the activated NEG coated tube is 2600 molecules/ion. The desorption yields after saturation for CH4, H-2, and CO2 were found to be very close to the yields measured after the activation, while CO increased by up to a factor of 5. The total desorption yield for the saturated tube is up to 7000 molecules/ion. The large value of the desorption yield of the activated NEG coated   tube, an order of magnitude higher than the desorption yield from a stainless steel tube at normal incident angle, could be explained by the grazing incident angle.

• 16.
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 Materials Science. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
Ar ion induced desorption yields at the energies 5-17.7 MeV/u2009In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 599, no 1, p. 1-8Article in journal (Refereed)

Particle accelerators have, during operation with heavy ion beams, shown a significant pressure rise when the intensity of the beam is increased. This pressure rise is due to ion induced desorption, which is the result of beam ions colliding with residual gas atoms in the beam pipe, where they undergo charge exchange. This causes them to hit the vacuum chamber after the next dipole magnet and gas to be released. For the upgrade of the SIS18 synchrotron at GSI the intensity has to be a few orders of magnitude higher than it is today at the injection energy of 10 MeV/u. The aim of this experiment is to measure desorption yields, η, (released molecules per incident ion) from materials commonly used in accelerators: 316LN stainless steel, Cu, etched Cu, gold coated Cu and Ta, using an Ar beam at impact energies in the range of 5–17.7 MeV/u for perpendicular incidence. The measured initial desorption yields vary for the same material from sample to sample: up to 4.5 times for stainless steel and up to 3 times for etched Cu. Therefore more samples should be studied to have better statistics. Beam conditioning at lower energy does not significantly reduce the desorption yield at higher energy. There is a significant difference of up to a few times in desorption yield between flat and tubular samples. The desorption yield from a Cu sample at grazing incident angle of 125 mrad was an order of magnitude larger than at normal incident angle. It was found that the total number of positively and negatively charged secondary particles, emitted from the surface bombarded with heavy ions, does not exceed 40 secondary particles per impact heavy ion. The current of negatively charged particles was about 2.3 times larger than the current for positively charged particles. The impact from secondary particles on dynamic gas pressure was not possible to investigate.

• 17.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Studies of Heavy Ion Induced Desorption in the Energy Range 5-100 MeV/u2008Doctoral thesis, comprehensive summary (Other academic)

During operation of heavy ion accelerators a significant pressure rise has been observed when the intensity of the high energy beam was increased. The cause for this pressure rise is ion induced desorption, which is the result when beam ions collide with residual gas molecules in the accelerator, whereby they undergo charge exchange. Since the change in charge state will affect the bending radius of the particles after they have passed a bending magnet, they will not follow the required trajectory but instead collide with the vacuum chamber wall and gas are released. For the Future GSI project FAIR (Facility for Antiproton and Ion Research) there is a need to upgrade the SIS18 synchrotron in order to meet the requirements of the increased intensity. The aim of this work was to measure the desorption yields, η, (released molecules per incident ion) from materials commonly used in accelerators: 316LN stainless steel, Cu, Etched Cu, gold coated Cu, Ta and TiZrV coated stainless steel with argon and uranium beams at the energies 5-100 MeV/u. The measurements were performed at GSI and at The Svedberg Laboratory where a new dedicated teststand was built. It was found that the desorption yield scales with the electronic energy loss to the second power, decreasing for increasing impact energy above the Bragg Maximum. A feasibility study on the possibility to use laser refractometry to improve the accuracy of a specific throughput system was performed. The result was an improvement by up to 3 orders of magnitude, depending on pressure range.

1. Heavy-Ion-Induced Electronic Desorption of Gas from Metals
Open this publication in new window or tab >>Heavy-Ion-Induced Electronic Desorption of Gas from Metals
2007 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 98, no 6, p. 064801-Article in journal (Refereed) Published
##### Abstract [en]

During heavy-ion operation in several particle accelerators worldwide, dynamic pressure rises of orders of magnitude were triggered by lost beam ions that bombarded the vacuum chamber walls. This ion-induced molecular desorption, observed at CERN, GSI, and BNL, can seriously limit the ion beam lifetime and intensity of the accelerator. From dedicated test stand experiments we have discovered that heavy-ion-induced gas desorption scales with the electronic energy loss (dEe/dx) of the ions slowing down in matter; but it varies only little with the ion impact angle, unlike electronic sputtering.

##### Keywords
Positive-ion beams, Interactions of atoms and molecules with surfaces; photon and electron emission; neutralization of ions, Atomic, molecular, and ion beam impact and interactions with surfaces
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-97073 (URN)10.1103/PhysRevLett.98.064801 (DOI)000244117400034 ()
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-14Bibliographically approved
2. A new test stand for heavy ion induced gas desorption measurements at TSL
Open this publication in new window or tab >>A new test stand for heavy ion induced gas desorption measurements at TSL
2008 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 586, no 3, p. 377-381Article in journal (Refereed) Published
##### Abstract [en]

In several experiments at CERN, GSI and BNL it has been found that the lifetime of highly energetic heavy ions in synchrotrons decreases with increasing number of injected ions. This phenomenon occurs due to the collisions of beam ions and residual gas molecules leading to the change of charge of the ions and their loss on the vacuum chamber walls, which in turn cause ion-induced gas desorption and further pressure increase. To gain a deeper understanding of the ion-induced desorption process in the energy range 5-45 MeV/u, a dedicated test stand was built at the end of the K beamline at The Svedberg Laboratory (TSL) in Uppsala, Sweden. The energy range was chosen due to the fact that the injection energy of the heavy ion synchrotron SIS18 at GSI will be 10 MeV/u, and that there are insufficient data in this energy range. A Test Particle Monte-Carlo model of the experimental set-up was build-up, run and analysed for different sample configurations. An important result is that for the same sample material the desorption yield from a flat sample causes a 1.58 times larger pressure increase than that of a tubular sample. A detailed explanation of the set-up is presented.

##### Keywords
ultrahigh vacuum, heavy-ion-induced desorption, test particles Monte-Carlo
##### National Category
Physical Sciences Engineering and Technology
##### Identifiers
urn:nbn:se:uu:diva-97074 (URN)10.1016/j.nima.2007.12.020 (DOI)000253960800001 ()
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-14Bibliographically approved
3. Ar ion induced desorption yields at the energies 5-17.7 MeV/u
Open this publication in new window or tab >>Ar ion induced desorption yields at the energies 5-17.7 MeV/u
2009 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 599, no 1, p. 1-8Article in journal (Refereed) Published
##### Abstract [en]

Particle accelerators have, during operation with heavy ion beams, shown a significant pressure rise when the intensity of the beam is increased. This pressure rise is due to ion induced desorption, which is the result of beam ions colliding with residual gas atoms in the beam pipe, where they undergo charge exchange. This causes them to hit the vacuum chamber after the next dipole magnet and gas to be released. For the upgrade of the SIS18 synchrotron at GSI the intensity has to be a few orders of magnitude higher than it is today at the injection energy of 10 MeV/u. The aim of this experiment is to measure desorption yields, η, (released molecules per incident ion) from materials commonly used in accelerators: 316LN stainless steel, Cu, etched Cu, gold coated Cu and Ta, using an Ar beam at impact energies in the range of 5–17.7 MeV/u for perpendicular incidence. The measured initial desorption yields vary for the same material from sample to sample: up to 4.5 times for stainless steel and up to 3 times for etched Cu. Therefore more samples should be studied to have better statistics. Beam conditioning at lower energy does not significantly reduce the desorption yield at higher energy. There is a significant difference of up to a few times in desorption yield between flat and tubular samples. The desorption yield from a Cu sample at grazing incident angle of 125 mrad was an order of magnitude larger than at normal incident angle. It was found that the total number of positively and negatively charged secondary particles, emitted from the surface bombarded with heavy ions, does not exceed 40 secondary particles per impact heavy ion. The current of negatively charged particles was about 2.3 times larger than the current for positively charged particles. The impact from secondary particles on dynamic gas pressure was not possible to investigate.

##### Keywords
Ultra high vacuum, Heavy ion induced desorption, Heavy ion accelerators
##### National Category
Physical Sciences Engineering and Technology
##### Identifiers
urn:nbn:se:uu:diva-97075 (URN)10.1016/j.nima.2008.09.052 (DOI)000263205100001 ()
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-14Bibliographically approved
4. Energy Scaling of the Ion-Induced Desorption Yield for Perpendicular Collisions of Ar and U with Stainless Steel in the Energy Range between 5 and 100 MeV/u
Open this publication in new window or tab >>Energy Scaling of the Ion-Induced Desorption Yield for Perpendicular Collisions of Ar and U with Stainless Steel in the Energy Range between 5 and 100 MeV/u
2009 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 27, no 2, p. 245-247Article in journal (Refereed) Published
##### Abstract [en]

For the GSI future project Facility for Antiproton and Ion Research a beam intensity of 10(12)U(28+)ions/s is planned to be extracted from the GSI heavy ion synchrotron SIS18. Measurements performed in 2001 showed that the beam lifetime of the ions in the synchrotron is decreasing with increasing number of injected particles due to vacuum   instabilities caused by ion-induced desorption. The injection energy for the SIS18 is about 10 MeV/u and U28+ ions are accelerated to 200 MeV/u limited by the magnetic rigidity for the low charge state. The aim of this work was to measure the desorption yield as a function of   the impact energy from injection to extraction of SIS18 at GSI. Low energy yields at 5.0, 9.7, and 17.7 MeV/u were measured at the Cyclotron of The Svedberg Laboratory in Uppsala. High energy yields at 40, 80, and 100 MeV/u were measured at SIS18 of GSI in a different   setup. It was found that the desorption yield scales with the electronic energy loss (dE/dx)(el)(n), with n between 2 and 3, decreasing for increasing impact energy above the Bragg maximum.

##### National Category
Physical Sciences Engineering and Technology
##### Identifiers
urn:nbn:se:uu:diva-97076 (URN)10.1116/1.3065979 (DOI)000264017500012 ()
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-14Bibliographically approved
5. Heavy-Ion Induced Desorption of a TiZrV Coated Vacuum Chamber Bombarded with 5 MeV/u Ar8+ beam at grazing incidence
Open this publication in new window or tab >>Heavy-Ion Induced Desorption of a TiZrV Coated Vacuum Chamber Bombarded with 5 MeV/u Ar8+ beam at grazing incidence
2009 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 27, no 1, p. 139-144Article in journal (Refereed) Published
##### Abstract [en]

TiZrV nonevaporable getter (NEG) coated vacuum chambers is a new vacuum technology which is already used in many particle accelerators worldwide. This coating is also of interest for heavy-ion accelerator vacuum chambers. Heavy-ion desorption yields from an activated as well as a CO saturated NEG coated tube have been measured with 5 MeV/u Ar8+ beam. The sticking probability of the NEG film was obtained by using the partial pressure ratios on two sides of the NEG coated tube. These ratios were compared to results of modeling of the experimental setup with test particle Monte Carlo and angular coefficient methods. The   partial pressures inside the saturated NEG coated tube bombarded with heavy ions were up to 20 times larger than those inside the activated one. However, the partial pressure of methane remained the same. The value of the total desorption yield from the activated NEG coated tube is 2600 molecules/ion. The desorption yields after saturation for CH4, H-2, and CO2 were found to be very close to the yields measured after the activation, while CO increased by up to a factor of 5. The total desorption yield for the saturated tube is up to 7000 molecules/ion. The large value of the desorption yield of the activated NEG coated   tube, an order of magnitude higher than the desorption yield from a stainless steel tube at normal incident angle, could be explained by the grazing incident angle.

##### Keywords
carbon compounds, desorption, hydrogen, ion beam effects, metallic thin films, Monte Carlo methods, titanium alloys, vanadium alloys, zirconium alloys
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-97077 (URN)10.1116/1.3032914 (DOI)000264017300019 ()
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-14Bibliographically approved
6. Improved determination of the gas flow rate for UHV and leak metrology with laser refractometry
Open this publication in new window or tab >>Improved determination of the gas flow rate for UHV and leak metrology with laser refractometry
2006 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 17, no 10, p. 2767-2772Article in journal (Refereed) Published
##### Abstract [en]

A system often used for vacuum metrology purposes in order to calibrate vacuum gauges in the UHV region and to calibrate gas leak rates is the throughput system, employing the continuous ( or dynamic) expansion method. An important component in such systems is the flowmeter, which has to deliver a pure and well-determined gas flow into the system. To determine the generated gas flow, a number of factors including the pressure inside the flowmeter have to be determined. However, it has turned out that the calibration uncertainty when measuring the pressure in the flowmeter gives a main contribution to the total uncertainty (of typically about 0.1%) for the generated flow, thereby limiting the accuracies of the generated vacuum pressure as well as gas leak rates in UHV metrology. A feasibility study is reported in this paper about the possibility of using laser refractometry to monitor dynamic gas density in situ in the flowmeter, as an alternative and possibly more accurate means of determining the generated gas flow, thereby potentially improving the calibration gas leak rates in the range 10(-8) - 10(-4) Pa m(3) s(-1).

##### Keywords
laser refractometry, gas flow, metrology, throughput, UHV
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-97078 (URN)10.1088/0957-0233/17/10/031 (DOI)000241989700033 ()
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-14Bibliographically approved
7. Addendum to ‘Improved determination of the gas flow rate for UHV and leak metrology with laser refractometry’
Open this publication in new window or tab >>Addendum to ‘Improved determination of the gas flow rate for UHV and leak metrology with laser refractometry’
2007 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 18, no 11, p. 3661-3663Article in journal (Refereed) Published
##### Abstract [en]

Clarification is provided for certain expressions quoted in Hedlund and Pendrill (2006 Meas. Sci. Technol. 17 2767-72).

##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-97079 (URN)10.1088/0957-0233/18/11/052 (DOI)
Available from: 2008-04-18 Created: 2008-04-18 Last updated: 2017-12-14Bibliographically approved
• 18.
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Nuclear and Particle Physics.
Fragmentation in Proton-Nucleus Reactions from 100 to 1400 MeV2008Doctoral thesis, comprehensive summary (Other academic)

The heaviest fragments, recoils, have been studied in proton and deuteron induced 28Si reactions and proton-20Ne reactions at 100-300 MeV per nucleon. Inclusive charge and angular distributions and coincidences between He nuclei and recoils have been compared to two theoretical models, Dubna Cascade Model and JAERI Quantum Molecular Dynamics. The overall agreement was good for the reactions with 28Si, however the angular distributions of He fragments could not be reproduced.

For the 20Ne reactions the recoil angular distributions were only reproduced for large angles. There was a significant underestimation at small angles and low recoil charge. α-clustering in the bombarding nucleus is a possible explanation for the deviations. In the 100 MeV per nucleon reactions all assumptions of the models may not be valid and the agreement was worst for these reactions.

In proton-natXe reactions intermediate mass fragments have been studied from 200 to 1400 MeV. Slow ramping was used to scan the energy. Charge distributions and a caloric curve have been compared to Cascade Fragmentation Evaporation Model. Charge distributions showed good agreement for fragments with Z<8 but the heavier fragments were underestimated.

1. Probing the liquid–gas coexistence in p+Xe reactions from 200 to 1400 MeV
Open this publication in new window or tab >>Probing the liquid–gas coexistence in p+Xe reactions from 200 to 1400 MeV
2007 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 644, no 4, p. 228-231Article in journal (Refereed) Published
##### Abstract [en]

The nuclear equation of state (EOS) is probed from statistical parameters, determined in an excitation function experiment on p + Xe-nat reactions at 200-1400 MeV. Total charge (Z) distributions follow a cascade-[multi]fragmentation-evaporation (CFEM) model well. The caloric curve in regions supposedly dominated by fast processes is compatible with a pure statistical multifragmentation (SMM) process, where the temperature (T)-excitation energy (epsilon*) relation starts in the Fermi liquid phase and progresses into a liquid/gas coexistence region, where it remains up to 1400 MeV. A local peak in T at epsilon* = 2.1 MeV agrees with the idea of sudden fragmentation.

##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-96827 (URN)10.1016/j.physletb.2006.11.049 (DOI)000243801600003 ()
Available from: 2008-03-14 Created: 2008-03-14 Last updated: 2017-12-14Bibliographically approved
2. A detector system for studying nuclear reactions relevant to Single Event Effects
Open this publication in new window or tab >>A detector system for studying nuclear reactions relevant to Single Event Effects
2007 (English)In: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, ISSN 0168-9002, E-ISSN 1872-9576, Vol. 578, no 2, p. 385-398Article in journal (Refereed) Published
##### Abstract [en]

We describe a device to study reactions relevant for the Single Event Effect (SEE) in microelectronics by means of 200 A and 300 A MeV, inverse kinematics, Si+H and Si+D reactions. The work is focused on the possibility to measure Z=2–14 projectile fragments as efficiently as possible. During commissioning and first experiments the fourth quadrant of the CELSIUS storage ring acted as a spectrometer to register fragments in two planes of Si strip detectors in the angular region 0–0.6. A combination of ring-structured and sector-structured Si strip detector planes operated at angles 0.6–1.1. For specific event tagging a Si+ phoswich scintillator wall operated in the range 3.9–11.7 and Si ΔEE telescopes of CHICSi type operated at large angles.

##### Keywords
Single event effects, Fragmentation detectors, Inverse kinematics
##### National Category
Physical Sciences
##### Identifiers
urn:nbn:se:uu:diva-16747 (URN)10.1016/j.nima.2007.05.318 (DOI)000248930700004 ()
Available from: 2008-06-05 Created: 2008-06-05 Last updated: 2017-12-08
3. 200 and 300 MeV/nucleon Nuclear Reactions Responsible for Single-Event Effecrs in Microelectronics
Open this publication in new window or tab >>200 and 300 MeV/nucleon Nuclear Reactions Responsible for Single-Event Effecrs in Microelectronics
Article in journal (Refereed) Submitted
##### Identifiers
urn:nbn:se:uu:diva-96829 (URN)
Available from: 2008-03-14 Created: 2008-03-14Bibliographically approved
4. Inclusive production of recoils in 20Ne + 1H reactions ar 100 and 300 MeV/nucleon
Open this publication in new window or tab >>Inclusive production of recoils in 20Ne + 1H reactions ar 100 and 300 MeV/nucleon