|
|
Study of jet fragmentation and inclusive jet production in heavy-ion collisions with the ATLAS experiment
Slovák, Radim ; Spousta, Martin (advisor) ; Bielčíková, Jana (referee) ; Taševský, Marek (referee)
Title: Study of jet fragmentation and inclusive jet production in heavy-ion colli- sions with the ATLAS experiment Author: Mgr. Radim Slovák Institute: Institute of Particle and Nuclear Physics Supervisor: Mgr. Martin Spousta, Ph.D., Institute of Particle and Nuclear Physics, Charles University Abstract: This thesis presents two measurements - measurement of the jet frag- mentation functions and inclusive jet production in heavy-ion collisions. The frag- mentation functions are measured in Pb+Pb and pp collisions with the ATLAS detector at the LHC. The distributions are measured as a function of jet trans- verse momentum and rapidity. The analysis utilises an integrated luminosity of 0.14 nb−1 of Pb+Pb data and 4.0 pb−1 of pp data collected in 2011 and 2013, respectively, at the same centre-of-mass energy of 2.76 TeV. Modest but signif- icant centrality-dependent modifications of fragmentation functions in Pb+Pb collisions with respect to those in pp collisions are seen. Measurements of the yield and nuclear modification factor, RAA, for inclusive jets are performed us- ing 25 pb−1 of pp data at √ s = 5.02 TeV and 0.49 nb−1 of Pb+Pb data at √ sNN = 5.02 TeV. The jets are measured over the transverse momentum range of 100-1000 GeV in six rapidity intervals covering |y| < 2.8. The magnitude of the RAA...
|
|
|
Study of proton-proton and heavy-ion collisions with the ATLAS experiment at the LHC
Balek, Petr ; Dolejší, Jiří (advisor) ; Scheirich, Daniel (referee) ; Šumbera, Michal (referee)
Title: Study of proton-proton and heavy-ion collisions with the ATLAS experi- ment at the LHC Author: Mgr. Petr Balek Department: Institute of Particle and Nuclear Physics Supervisor: Doc. RNDr. Jiří Dolejší, CSc. Abstract: The presented results show a suppression in a production of charged hadrons in heavy-ion collisions with respect to the production measured in proton- proton collisions. Lead-lead data at √ sNN = 2.76 TeV were recorded by the AT- LAS experiment at the LHC in 2010 and 2011 and they have a total integrated luminosity of 0.15 nb−1 , and proton-proton data at √ s = 2.76 TeV were recorded in 2011 and 2013 having an integrated luminosity of 4.2 nb−1 . The results are presented in wide transverse momentum (0.5 < pT < 150 GeV) and pseudorapid- ity (|η| < 2) ranges, and also in different centrality intervals of Pb+Pb collisions. Nuclear modification factor RAA shows a clear pT-dependence with a minimum at around 7 GeV, however above 60 GeV, it reaches a plateau with no significant pT-dependence. As a function of |η|, the RAA is flat over whole pT region. Keywords: ATLAS detector, heavy-ion collisions, charged-hadron spectra, nuclear modification factor RAA
|
|
|
Measurement of the Λb baryon mass in the ATLAS experiment
Macko, Vladimír ; Scheirich, Daniel (advisor) ; Faltová, Jana (referee)
The mass of the Λb baryon has been studied in proton-proton collisions using experimental data from the ATLAS detector at the LHC in CERN. The mass is measured by reconstructing momenta of products in the studied decay. Decay channel Λb → J/ψ(µ+ µ− )Λ(pπ− ) is chosen for the mass reconstruction in this work. The selection criteria are applied in order to minimize background effect and, therefore, obtain the value of the mass of the Λb baryon with the lower statistical error. The systematic error is obtained from a comparison of the three statistical models describing experimental data. The result of measurement of the Λb baryon mass in the ATLAS experiment performed in this work is: mΛb = (5619.1 ± 1.0) MeV. 1
|
|
|
Study of jet fragmentation and inclusive jet production in heavy-ion collisions with the ATLAS experiment
Slovák, Radim ; Spousta, Martin (advisor) ; Bielčíková, Jana (referee) ; Taševský, Marek (referee)
Title: Study of jet fragmentation and inclusive jet production in heavy-ion colli- sions with the ATLAS experiment Author: Mgr. Radim Slovák Institute: Institute of Particle and Nuclear Physics Supervisor: Mgr. Martin Spousta, Ph.D., Institute of Particle and Nuclear Physics, Charles University Abstract: This thesis presents two measurements - measurement of the jet frag- mentation functions and inclusive jet production in heavy-ion collisions. The frag- mentation functions are measured in Pb+Pb and pp collisions with the ATLAS detector at the LHC. The distributions are measured as a function of jet trans- verse momentum and rapidity. The analysis utilises an integrated luminosity of 0.14 nb−1 of Pb+Pb data and 4.0 pb−1 of pp data collected in 2011 and 2013, respectively, at the same centre-of-mass energy of 2.76 TeV. Modest but signif- icant centrality-dependent modifications of fragmentation functions in Pb+Pb collisions with respect to those in pp collisions are seen. Measurements of the yield and nuclear modification factor, RAA, for inclusive jets are performed us- ing 25 pb−1 of pp data at √ s = 5.02 TeV and 0.49 nb−1 of Pb+Pb data at √ sNN = 5.02 TeV. The jets are measured over the transverse momentum range of 100-1000 GeV in six rapidity intervals covering |y| < 2.8. The magnitude of the RAA...
|
|
|
Study of proton-proton and heavy-ion collisions with the ATLAS experiment at the LHC
Balek, Petr ; Dolejší, Jiří (advisor) ; Scheirich, Daniel (referee) ; Šumbera, Michal (referee)
Title: Study of proton-proton and heavy-ion collisions with the ATLAS experi- ment at the LHC Author: Mgr. Petr Balek Department: Institute of Particle and Nuclear Physics Supervisor: Doc. RNDr. Jiří Dolejší, CSc. Abstract: The presented results show a suppression in a production of charged hadrons in heavy-ion collisions with respect to the production measured in proton- proton collisions. Lead-lead data at √ sNN = 2.76 TeV were recorded by the AT- LAS experiment at the LHC in 2010 and 2011 and they have a total integrated luminosity of 0.15 nb−1 , and proton-proton data at √ s = 2.76 TeV were recorded in 2011 and 2013 having an integrated luminosity of 4.2 nb−1 . The results are presented in wide transverse momentum (0.5 < pT < 150 GeV) and pseudorapid- ity (|η| < 2) ranges, and also in different centrality intervals of Pb+Pb collisions. Nuclear modification factor RAA shows a clear pT-dependence with a minimum at around 7 GeV, however above 60 GeV, it reaches a plateau with no significant pT-dependence. As a function of |η|, the RAA is flat over whole pT region. Keywords: ATLAS detector, heavy-ion collisions, charged-hadron spectra, nuclear modification factor RAA
|
|
|
Measurement of the Λb baryon mass in the ATLAS experiment
Macko, Vladimír ; Scheirich, Daniel (advisor) ; Faltová, Jana (referee)
The mass of the Λb baryon has been studied in proton-proton collisions using experimental data from the ATLAS detector at the LHC in CERN. The mass is measured by reconstructing momenta of products in the studied decay. Decay channel Λb → J/ψ(µ+ µ− )Λ(pπ− ) is chosen for the mass reconstruction in this work. The selection criteria are applied in order to minimize background effect and, therefore, obtain the value of the mass of the Λb baryon with the lower statistical error. The systematic error is obtained from a comparison of the three statistical models describing experimental data. The result of measurement of the Λb baryon mass in the ATLAS experiment performed in this work is: mΛb = (5619.1 ± 1.0) MeV. 1
|
guest ::
