Dijet azimuthal correlations and conditional yields in <i>pp</i> and <i>p</i> plus Pb collisions ats √<i>S<sub>NN</sub></i>=5.02 TeV with the ATLAS detector

Aaboud, M, Aad, G, Abbott, B, Abbott, DC, Abdinov, O, Abeloos, B, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL
et al (show 2855 more authors) (2019) Dijet azimuthal correlations and conditional yields in <i>pp</i> and <i>p</i> plus Pb collisions ats √<i>S<sub>NN</sub></i>=5.02 TeV with the ATLAS detector. PHYSICAL REVIEW C, 100 (3). 034903-.

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This paper 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 of the nuclear gluon density in regions where the fraction of the average momentum per nucleon carried by the parton entering the hard scattering 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 $\sqrt{s_{\rm NN}}$ = 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 rapidity range between $-$4.0 and 4.0 using the two highest transverse momentum jets in each event, with the highest transverse momentum jet restricted to the forward rapidity range. No significant broadening of azimuthal angular correlations is observed for forward-forward or forward-central dijets in $p$+Pb compared to $pp$ collisions. For forward-forward jet pairs in the proton-going direction, the ratio of conditional yields in $p$+Pb collisions to those in $pp$ collisions is suppressed by approximately 20%, with no significant dependence on the transverse momentum of the dijet system. No modification of conditional yields is observed for forward-central dijets.

Item Type: Article
Additional Information: 36 pages in total, author list starting page 20, 8 figures, 1 table, to be submitted to Phys. Rev. C. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2017-06
Uncontrolled Keywords: nucl-ex, nucl-ex, hep-ex
Depositing User: Symplectic Admin
Date Deposited: 07 Oct 2019 12:05
Last Modified: 19 Oct 2023 08:57
DOI: 10.1103/PhysRevC.100.034903
Open Access URL: https://doi.org/10.1103/PhysRevC.100.034903
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3057335