Dijet azimuthal correlations and conditional yields in pp and p+Pb collisions at q SNN = 5.02 TeV with the atlas detector

Kulinich, Yakov

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https://hdl.handle.net/2142/102417 Copy

Description

Title

Dijet azimuthal correlations and conditional yields in pp and p+Pb collisions at q SNN = 5.02 TeV with the atlas detector

Author(s)

Kulinich, Yakov

Issue Date

2018-10-30

Director of Research (if dissertation) or Advisor (if thesis)

• Grosse Perdekamp, Matthias
• Sickles, Anne M

Doctoral Committee Chair(s)

Yang, Liang

Committee Member(s)

• Willenbrock, Scott
• Bezryadin, Alexey

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

nuclear physics, proton structure

Abstract

This dissertation presents a measurement of forward--forward and forward--central dijet azimuthal angular correlations and conditional yields in proton--proton ($pp$) and proton--lead ($p$+Pb) collisions as a probe for possible gluon-density saturation in regions where the momentum fraction of a parton compared to a nucleon in the lead nucleus is low. In these regions, gluon saturation can modify the rapidly increasing parton distribution function of the gluon. The analysis utilizes 25 pb$^{-1}$ of $pp$ data and 360 $\mu \mathrm{b}^{-1}$ of $p$+Pb data, both at $\sqrt{s_{_{\mathrm{NN}}}}$ = 5.02 TeV, collected in 2015 and 2016, respectively, with the ATLAS detector at the LHC. The measurement is performed in the center-of-mass frame of the nucleon--nucleon system in the center-of-mass rapidity range between -4.0 and 4.0 using the two highest transverse momentum jets in each event. The highest transverse momentum jet is restricted to the forward rapidity range where it is possible to probe the region where the momentum fraction of a parton compared to a nucleon in the lead nucleus is low. No significant broadening of azimuthal angular correlations is observed for forward--forward or forward--central dijets in $p$+Pb compared to $pp$ collisions within the uncertainties. The ratio of conditional yields of forward--forward jet pairs in the proton-going direction in $p$+Pb collisions compared to $pp$ collisions is suppressed by approximately 20\%, with no significant dependence on the transverse momentum of the dijets system. No modification of conditional yields is observed for forward--central dijets.

Graduation Semester

2018-12

Type of Resource

text

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http://hdl.handle.net/2142/102417

Copyright and License Information

Copyright 2018 Yakov Kulinich

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