Constraining Gluon Distributions in Nuclei Using Dijets in Proton-Proton and Proton-Lead Collisions at sNN =5.02 TeV

CMS Collaboration

doi:10.1103/PhysRevLett.121.062002

Constraining Gluon Distributions in Nuclei Using Dijets in Proton-Proton and Proton-Lead Collisions at sNN =5.02 TeV

CMS Collaboration

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

41 Scopus citations

Abstract

The pseudorapidity distributions of dijets as functions of their average transverse momentum (pTave) are measured in proton-lead (pPb) and proton-proton (pp) collisions. The data samples were collected by the CMS experiment at the CERN LHC, at a nucleon-nucleon center-of-mass energy of 5.02 TeV. A significant modification of the pPb spectra with respect to the pp spectra is observed in all pTave intervals investigated. The ratios of the pPb and pp distributions are compared to next-to-leading order perturbative quantum chromodynamics calculations with unbound nucleon and nuclear parton distribution functions (PDFs). These results give the first evidence that the gluon PDF at large Bjorken x in lead ions is strongly suppressed with respect to the PDF in unbound nucleons.

Original language	English (US)
Article number	062002
Journal	Physical review letters
Volume	121
Issue number	6
DOIs	https://doi.org/10.1103/PhysRevLett.121.062002
State	Published - Aug 7 2018

Funding

We thank Nestor Armesto, Paukkunen Hannu, Pia Zurita, Petja Paakkinen and Carlos Salgado for the useful discussions and the NLO pQCD calculations with various nPDFs. We congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC and thank the technical and administrative staffs at CERN and at other CMS institutes for their contributions to the success of the CMS effort. In addition, we gratefully acknowledge the computing centers and personnel of the Worldwide LHC Computing Grid for delivering so effectively the computing infrastructure essential to our analyses. Finally, we acknowledge the enduring support for the construction and operation of the LHC and the CMS detector provided by the following funding agencies: BMWFW and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES and CSF (Croatia); RPF (Cyprus); SENESCYT (Ecuador); MoER, ERC IUT, and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); NKFIA (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT, LNS, SEP, and UASLP-FAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR (Russia); MESTD (Serbia); SEIDI, CPAN, PCTI and FEDER (Spain); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR, and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU and SFFR (Ukraine); STFC (United Kingdom); DOE and NSF (USA).

ASJC Scopus subject areas

General Physics and Astronomy

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10.1103/PhysRevLett.121.062002

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@article{99cd49e9cc1a49f2b23b28a935058393,

title = "Constraining Gluon Distributions in Nuclei Using Dijets in Proton-Proton and Proton-Lead Collisions at sNN =5.02 TeV",

abstract = "The pseudorapidity distributions of dijets as functions of their average transverse momentum (pTave) are measured in proton-lead (pPb) and proton-proton (pp) collisions. The data samples were collected by the CMS experiment at the CERN LHC, at a nucleon-nucleon center-of-mass energy of 5.02 TeV. A significant modification of the pPb spectra with respect to the pp spectra is observed in all pTave intervals investigated. The ratios of the pPb and pp distributions are compared to next-to-leading order perturbative quantum chromodynamics calculations with unbound nucleon and nuclear parton distribution functions (PDFs). These results give the first evidence that the gluon PDF at large Bjorken x in lead ions is strongly suppressed with respect to the PDF in unbound nucleons.",

author = "{CMS Collaboration} and Sirunyan, {A. M.} and A. Tumasyan and W. Adam and F. Ambrogi and E. Asilar and T. Bergauer and J. Brandstetter and M. Dragicevic and J. Er{\"o} and {Escalante Del Valle}, A. and M. Flechl and R. Fr{\"u}hwirth and Ghete, {V. M.} and J. Hrubec and M. Jeitler and N. Krammer and I. Kr{\"a}tschmer and D. Liko and T. Madlener and I. Mikulec and N. Rad and H. Rohringer and J. Schieck and R. Sch{\"o}fbeck and M. Spanring and D. Spitzbart and A. Taurok and W. Waltenberger and J. Wittmann and Wulz, {C. E.} and M. Zarucki and V. Chekhovsky and V. Mossolov and {Suarez Gonzalez}, J. and {De Wolf}, {E. A.} and {Di Croce}, D. and X. Janssen and J. Lauwers and M. Pieters and {Van De Klundert}, M. and {Van Haevermaet}, H. and {Van Mechelen}, P. and {Van Remortel}, N. and {Abu Zeid}, S. and F. Blekman and J. D'Hondt and {De Bruyn}, I. and Hahn, {K. A.} and Schmitt, {M. H.} and M. Velasco",

note = "Publisher Copyright: {\textcopyright} 2018 CERN. for the CMS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP.",

year = "2018",

month = aug,

day = "7",

doi = "10.1103/PhysRevLett.121.062002",

language = "English (US)",

volume = "121",

journal = "Physical review letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "6",

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T1 - Constraining Gluon Distributions in Nuclei Using Dijets in Proton-Proton and Proton-Lead Collisions at sNN =5.02 TeV

AU - CMS Collaboration

AU - Sirunyan, A. M.

AU - Tumasyan, A.

AU - Adam, W.

AU - Ambrogi, F.

AU - Asilar, E.

AU - Bergauer, T.

AU - Brandstetter, J.

AU - Dragicevic, M.

AU - Erö, J.

AU - Escalante Del Valle, A.

AU - Flechl, M.

AU - Frühwirth, R.

AU - Ghete, V. M.

AU - Hrubec, J.

AU - Jeitler, M.

AU - Krammer, N.

AU - Krätschmer, I.

AU - Liko, D.

AU - Madlener, T.

AU - Mikulec, I.

AU - Rad, N.

AU - Rohringer, H.

AU - Schieck, J.

AU - Schöfbeck, R.

AU - Spanring, M.

AU - Spitzbart, D.

AU - Taurok, A.

AU - Waltenberger, W.

AU - Wittmann, J.

AU - Wulz, C. E.

AU - Zarucki, M.

AU - Chekhovsky, V.

AU - Mossolov, V.

AU - Suarez Gonzalez, J.

AU - De Wolf, E. A.

AU - Di Croce, D.

AU - Janssen, X.

AU - Lauwers, J.

AU - Pieters, M.

AU - Van De Klundert, M.

AU - Van Haevermaet, H.

AU - Van Mechelen, P.

AU - Van Remortel, N.

AU - Abu Zeid, S.

AU - Blekman, F.

AU - D'Hondt, J.

AU - De Bruyn, I.

AU - Hahn, K. A.

AU - Schmitt, M. H.

AU - Velasco, M.

N1 - Publisher Copyright: © 2018 CERN. for the CMS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP.

PY - 2018/8/7

Y1 - 2018/8/7

N2 - The pseudorapidity distributions of dijets as functions of their average transverse momentum (pTave) are measured in proton-lead (pPb) and proton-proton (pp) collisions. The data samples were collected by the CMS experiment at the CERN LHC, at a nucleon-nucleon center-of-mass energy of 5.02 TeV. A significant modification of the pPb spectra with respect to the pp spectra is observed in all pTave intervals investigated. The ratios of the pPb and pp distributions are compared to next-to-leading order perturbative quantum chromodynamics calculations with unbound nucleon and nuclear parton distribution functions (PDFs). These results give the first evidence that the gluon PDF at large Bjorken x in lead ions is strongly suppressed with respect to the PDF in unbound nucleons.

AB - The pseudorapidity distributions of dijets as functions of their average transverse momentum (pTave) are measured in proton-lead (pPb) and proton-proton (pp) collisions. The data samples were collected by the CMS experiment at the CERN LHC, at a nucleon-nucleon center-of-mass energy of 5.02 TeV. A significant modification of the pPb spectra with respect to the pp spectra is observed in all pTave intervals investigated. The ratios of the pPb and pp distributions are compared to next-to-leading order perturbative quantum chromodynamics calculations with unbound nucleon and nuclear parton distribution functions (PDFs). These results give the first evidence that the gluon PDF at large Bjorken x in lead ions is strongly suppressed with respect to the PDF in unbound nucleons.

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DO - 10.1103/PhysRevLett.121.062002

M3 - Article

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AN - SCOPUS:85052065307

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VL - 121

JO - Physical review letters

JF - Physical review letters

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M1 - 062002

ER -

Constraining Gluon Distributions in Nuclei Using Dijets in Proton-Proton and Proton-Lead Collisions at sNN =5.02 TeV

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