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Buszello, Claus P
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Publications (10 of 467) Show all publications
Abazov, V. M., Abbott, B., Acharya, B. S., Adams, M., Adams, T., Agnew, J. P., . . . Zivkovic, L. (2017). Measurement of the direct CP violating charge asymmetry in B-+/- -> mu(+/-)nu D-mu(0) decays. Physical Review D: covering particles, fields, gravitation, and cosmology, 95(3), Article ID 031101.
Open this publication in new window or tab >>Measurement of the direct CP violating charge asymmetry in B-+/- -> mu(+/-)nu D-mu(0) decays
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2017 (English)In: Physical Review D: covering particles, fields, gravitation, and cosmology, ISSN 2470-0010, E-ISSN 2470-0029, Vol. 95, no 3, article id 031101Article in journal (Refereed) Published
Abstract [en]

We present the first measurement of the CP violating charge asymmetry in B-+/- -> mu(+/-)nu D-mu(0) decays using the full Run II integrated luminosity of 10.4 fb(-1) in proton-antiproton collisions collected with the D0 detector at the Fermilab Tevatron Collider. We measure a difference in the yield of B- and B+ mesons in these decays by fitting the reconstructed invariant mass distributions. This results in an asymmetry of A(mu D0) = [-0.14 +/- 0.20] %, which is consistent with standard model predictions.

National Category
Astronomy, Astrophysics and Cosmology
Identifiers
urn:nbn:se:uu:diva-317950 (URN)10.1103/PhysRevD.95.031101 (DOI)000393509100001 ()
Available from: 2017-04-03 Created: 2017-04-03 Last updated: 2017-11-29Bibliographically approved
Abazov, V. M., Abbott, B., Acharya, B. S., Adams, M., Adams, T., Agnew, J. P., . . . Zivkovic, L. (2017). Measurement of top quark polarization in t(t)over-bar lepton+jets final states. PHYSICAL REVIEW D, 95(1), Article ID 011101.
Open this publication in new window or tab >>Measurement of top quark polarization in t(t)over-bar lepton+jets final states
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2017 (English)In: PHYSICAL REVIEW D, ISSN 2470-0010, Vol. 95, no 1, article id 011101Article in journal (Refereed) Published
Abstract [en]

We present a measurement of top quark polarization in t (t) over bar pair production in p (p) over bar collisions at root s = 1.96 TeV using data corresponding to 9.7 fb(-1) of integrated luminosity recorded with the D0 detector at the Fermilab Tevatron Collider. We consider final states containing a lepton and at least three jets. The polarization is measured through the distribution of lepton angles along three axes: the beam axis, the helicity axis, and the transverse axis normal to the t (t) over bar production plane. This is the first measurement of top quark polarization at the Tevatron using lepton + jet final states and the first measurement of the transverse polarization in t (t) over bar production. The observed distributions are consistent with standard model predictions of nearly no polarization.

National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-316038 (URN)10.1103/PhysRevD.95.011101 (DOI)000391860700001 ()
Funder
German Research Foundation (DFG)Swedish Research Council
Available from: 2017-02-27 Created: 2017-02-27 Last updated: 2017-02-27Bibliographically approved
Abazov, V. M., Abbott, B., Acharya, B. S., Adams, M., Adams, T., Agnew, J. P., . . . Zivkovic, L. (2016). Measurement of the inclusive t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV and determination of the top quark pole mass. PHYSICAL REVIEW D, 94(9), Article ID 092004.
Open this publication in new window or tab >>Measurement of the inclusive t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV and determination of the top quark pole mass
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2016 (English)In: PHYSICAL REVIEW D, ISSN 2470-0010, Vol. 94, no 9, article id 092004Article in journal (Refereed) Published
Abstract [en]

The inclusive cross section of top quark-antiquark pairs produced in p (p) over bar collisions at root s = 1.96 TeV is measured in the lepton + jets and dilepton decay channels. The data sample corresponds to 9.7 fb(-1) of integrated luminosity recorded with the D0 detector during Run II of the Fermilab Tevatron Collider. Employing multivariate analysis techniques we measure the cross section in the two decay channels and we perform a combined cross section measurement. For a top quark mass of 172.5 GeV, we measure a combined inclusive top quark-antiquark pair production cross section of sigma(t<(t)over bar) = 7.26 +/- 0.13(stat)(-0.50)(+0.57) (syst) pb which is consistent with standard model predictions. We also perform a likelihood fit to the measured and predicted top quark mass dependence of the inclusive cross section, which yields a measurement of the pole mass of the top quark. The extracted value is m(t) = 172.8 +/- 1.1(theo)(-3.1)(+3.3) (exp) GeV.

National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-311503 (URN)10.1103/PhysRevD.94.092004 (DOI)000388526300002 ()
Funder
German Research Foundation (DFG)Swedish Research Council
Available from: 2016-12-30 Created: 2016-12-28 Last updated: 2016-12-30Bibliographically approved
Aad, G., Brenner, R., Buszello, C. P., Ekelöf, T., Ellert, M., Ferrari, A., . . . Zwalinski, L. (2016). Measurement of the t(t)over-bar production cross-section using e mu events with b-tagged jets in pp collisions at root s=7 and 8 TeV with the ATLAS detector. European Physical Journal C, 76(11), Article ID 642.
Open this publication in new window or tab >>Measurement of the t(t)over-bar production cross-section using e mu events with b-tagged jets in pp collisions at root s=7 and 8 TeV with the ATLAS detector
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2016 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 76, no 11, article id 642Article in journal (Refereed) Published
National Category
Subatomic Physics
Identifiers
urn:nbn:se:uu:diva-318898 (URN)10.1140/epjc/s10052-016-4501-2 (DOI)000394382800002 ()
Note

ATLAS Collaboration, for complete list of authors see dx.doi.org/10.1140/epjc/s10052-016-4501-2

Addendum till artikel med samma titel i: European Physical Journal C, Vol 74 (2014) s. 3109-

Available from: 2017-03-29 Created: 2017-03-29 Last updated: 2018-05-18Bibliographically approved
Aad, G., Bergeås, E. K., Brenner, R., Buszello, C. P., Ekelöf, T., Ellert, M., . . . Zwalinski, L. (2015). A search for high-mass resonances decaying to tau(+)tau(-) in pp collisions at root s=8 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP) (7), Article ID 157.
Open this publication in new window or tab >>A search for high-mass resonances decaying to tau(+)tau(-) in pp collisions at root s=8 TeV with the ATLAS detector
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2015 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 7, article id 157Article in journal (Refereed) Published
Abstract [en]

A search for high-mass resonances decaying into tau(+)tau(-) final states using proton-proton collisions at root s = 8 TeV produced by the Large Hadron Collider is presented. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 19.5-20.3 fb(-1). No statistically significant excess above the Standard Model expectation is observed; 95% credibility upper limits are set on the cross section times branching fraction of Z' resonances decaying into tau(+)tau(-) pairs as a function of the resonance mass. As a result, Z' bosons of the Sequential Standard Model with masses less than 2.02 TeV are excluded at 95% credibility. The impact of the fermionic couplings on the Z' acceptance is investigated and limits are also placed on a Z' model that exhibits enhanced couplings to third-generation fermions.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-261758 (URN)10.1007/JHEP07(2015)157 (DOI)000358928800001 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1007/JHEP07(2015)157

Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2017-12-04Bibliographically approved
Aad, G., Bergeås, E. K., Brenner, R., Buszello, C. P., Ekelöf, T., Ellert, M., . . . Zwalinski, L. (2015). Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at root s=8 TeV with the ATLAS detector. Journal of High Energy Physics (JHEP) (10), Article ID 150.
Open this publication in new window or tab >>Analysis of events with b-jets and a pair of leptons of the same charge in pp collisions at root s=8 TeV with the ATLAS detector
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2015 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 10, article id 150Article in journal (Refereed) Published
Abstract [en]

An analysis is presented of events containing jets including at least one b-tagged jet, sizeable missing transverse momentum, and at least two leptons including a pair of the same electric charge, with the scalar sum of the jet and lepton transverse momenta being large. A data sample with an integrated luminosity of 20.3 fb(-1) of pp collisions at root s = 8 TeV recorded by the ATLAS detector at the Large Hadron Collider is used. Standard Model processes rarely produce these final states, but there are several models of physics beyond the Standard Model that predict an enhanced rate of production of such events; the ones considered here are production of vector-like quarks, enhanced fourtop-quark production, pair production of chiral b '-quarks, and production of two positively charged top quarks. Eleven signal regions are defined; subsets of these regions are combined when searching for each class of models. In the three signal regions primarily sensitive to positively charged top quark pair production, the data yield is consistent with the background expectation. There are more data events than expected from background in the set of eight signal regions defined for searching for vector-like quarks and chiral b ' quarks, but the significance of the discrepancy is less than two standard deviations. The discrepancy reaches 2.5 standard deviations in the set of five signal regions defined for searching for four-top-quark production. The results are used to set 95% CL limits on various models.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-289041 (URN)10.1007/JHEP10(2015)150 (DOI)000363513700004 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1007/JHEP10(2015)150

Available from: 2016-04-28 Created: 2016-04-28 Last updated: 2017-11-30Bibliographically approved
Aad, G., Bergeås, E. K., Brenner, R., Buszello, C. P., Ekelöf, T., Ellert, M., . . . Zwalinski, L. (2015). Centrality and rapidity dependence of inclusive jet production in root(NN)-N-S=5.02 TeV proton-lead collisions with the ATLAS detector. Physics Letters B, 748, 392-413
Open this publication in new window or tab >>Centrality and rapidity dependence of inclusive jet production in root(NN)-N-S=5.02 TeV proton-lead collisions with the ATLAS detector
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2015 (English)In: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 748, p. 392-413Article in journal (Refereed) Published
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-262795 (URN)10.1016/j.physletb.2015.07.023 (DOI)000359146200061 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1016/j.physletb.2015.07.023 

Available from: 2015-09-21 Created: 2015-09-21 Last updated: 2017-12-04Bibliographically approved
Aad, G., Bergeås, E. K., Brenner, R., Buszello, C. P., Ekelöf, T., Ellert, M., . . . Zwalinski, L. (2015). Combined Measurement of the Higgs Boson Mass in pp Collisions at root s=7 and 8 TeV with the ATLAS and CMS Experiments. Physical Review Letters, 114(19), Article ID 191803.
Open this publication in new window or tab >>Combined Measurement of the Higgs Boson Mass in pp Collisions at root s=7 and 8 TeV with the ATLAS and CMS Experiments
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2015 (English)In: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 114, no 19, article id 191803Article in journal (Refereed) Published
Abstract [en]

A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H --> gamma gamma and H --> ZZ --> 4l decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is m(H) = 125.09 +/- 0.21 (stat) +/- 0.11 (syst) GeV.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-256633 (URN)10.1103/PhysRevLett.114.191803 (DOI)000354552000004 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1103/PhysRevLett.114.191803

Available from: 2015-06-24 Created: 2015-06-24 Last updated: 2017-12-04Bibliographically approved
Aad, G., Bergeås, E. K., Brenner, R., Buszello, C. P., Ekelöf, T., Ellert, M., . . . Zwalinski, L. (2015). Determination of spin and parity of the Higgs boson in the WW* -> ev mu v decay channel with the ATLAS detector. European Physical Journal C, 75(5), Article ID 231.
Open this publication in new window or tab >>Determination of spin and parity of the Higgs boson in the WW* -> ev mu v decay channel with the ATLAS detector
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2015 (English)In: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 75, no 5, article id 231Article in journal (Refereed) Published
Abstract [en]

Studies of the spin and parity quantum numbers of the Higgs boson in the WW* -> ev mu v final state are presented, based on proton-proton collision data collected by the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 20.3 fb(-1) at a centre-of-mass energy of root s = 8 TeV. The Standard Model spin-parity J(CP) = 0(++) hypothesis is compared with alternative hypotheses for both spin andCP. The case where the observed resonance is a mixture of the Standard-Model-like Higgs boson and CP-even (J(CP) = 0(++)) or CP-odd (J(CP) = 0(+-)) Higgs boson in scenarios beyond the Standard Model is also studied. The data are found to be consistent with the Standard Model prediction and limits are placed on alternative spin and CP hypotheses, including CP mixing in different scenarios.

National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-258302 (URN)10.1140/epjc/s10052-015-3436-3 (DOI)000355680900007 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1140/epjc/s10052-015-3436-3

Available from: 2015-07-13 Created: 2015-07-13 Last updated: 2017-12-04Bibliographically approved
Aad, G., Bergeås Kuutmann, E., Brenner, R., Buszello, C. P., Ekelöf, T., Ellert, M., . . . Zwalinski, L. (2015). Determination of the top-quark pole mass using t(t)over-bar+1-jet events collected with theATLAS experiment in 7 TeV pp collisions. Journal of High Energy Physics (JHEP) (10), Article ID 121.
Open this publication in new window or tab >>Determination of the top-quark pole mass using t(t)over-bar+1-jet events collected with theATLAS experiment in 7 TeV pp collisions
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2015 (English)In: Journal of High Energy Physics (JHEP), ISSN 1126-6708, E-ISSN 1029-8479, no 10, article id 121Article in journal (Refereed) Published
Abstract [en]

The normalized differential cross section for top-quark pair production in association with at least one jet is studied as a function of the inverse of the invariant mass of the t (t) over bar + 1-jet system. This distribution can be used for a precise determination of the top-quark mass since gluon radiation depends on the mass of the quarks. The experimental analysis is based on proton-proton collision data collected by the ATLAS detector at the LHC with a centre-of-mass energy of 7TeV corresponding to an integrated luminosity of 4.6 fb(-1). The selected events were identified using the lepton+jets top-quark-pair decay channel, where lepton refers to either an electron or a muon. The observed distribution is compared to a theoretical prediction at next-to-leading-order accuracy in quantum chromodynamics using the pole-mass scheme. With this method, the measured value of the top-quark pole mass, m(t)(pole), is: m(t)(pole) t = 173.7 +/- 1.5 (stat.) +/- 1.4 (syst.)(-0.5)(+1.0) (theory) GeV. This result represents the most precise measurement of the top-quark pole mass to date.

Keywords
Hadron-Hadron Scattering; Top physics
National Category
Subatomic Physics Accelerator Physics and Instrumentation
Identifiers
urn:nbn:se:uu:diva-268384 (URN)10.1007/JHEP10(2015)121 (DOI)000363476900001 ()
Note

ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1007/JHEP10(2015)121

Funding: We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWF and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; EPLANET, ERC and NSRF, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, DFG, HGF, MPG and AvH Foundation, Germany; GSRT and NSRF, Greece; ISF, MINERVA, GIF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; BRF and RCN, Norway; MNiSW and NCN, Poland; GRICES and FCT, Portugal; MNE/IFA, Romania; MES of Russia and ROSATOM, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MIZS Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, United Kingdom; DOE and NSF, United States of America.

Available from: 2015-12-04 Created: 2015-12-04 Last updated: 2017-12-01Bibliographically approved
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