Measurement of inclusive very forward jet cross sections in proton-lead collisions at p sNN=5:02 TeV
BMWFW ; FWF ; FNRS ; FWO (Belgium) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) ; Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ) ; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ; MES (Bulgaria) ; MoST ; NSFC (China) ; COLCIENCIAS (Colombia) ; CSF (Croatia) ; SENESCYT (Ecuador) ; MoER ; ERDF (Estonia) ; Academy of Finland ; MEC ; CEA ; CNRS/IN2P3 (France) ; BMBF ; DFG ; HGF (Germany) ; GSRT (Greece) ; NKFIA (Hungary) ; DAE ; DST ; IPM ; SFI (Ireland) ; INFN (Italy) ; NRF (Republic of Korea) ; MOE ; UM (Malaysia) ; BUAP, CINVESTAV ; CONACYT ; UASLP-FAI (Mexico) ; MBIE (New Zealand) ; PAEC (Pakistan) ; MSHE ; FCT (Portugal) ; JINR (Dubna) ; RosAtom ; RFBR ; MESTD (Serbia) ; SEIDI ; FEDER (Spain) ; Swiss Funding Agencies (Switzerland) ; NSTDA (Thailand) ; TUBITAK ; TAEK ; NASU ; SFFR (Ukraine) ; DOE ; NSF ; Marie-Curie program ; European Research Council ; Horizon 2020 Grant ; Leventis Foundation ; A.P. Sloan Foundation ; Alexander von Humboldt Foundation ; Belgian Federal Science Policy Office ; Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium) ; Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium) ; FWO (Belgium) under the Excellence of Science -EOS ; Ministry of Education, Youth and Sports (MEYS) of the Czech Republic ; Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences ; Council of Science and Industrial Research, India ; HOMING PLUS program of the Foundation for Polish Science ; European Union, Regional Development Fund ; Sonata-bis ; National Priorities Research Program by Qatar National Research Fund ; Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de Maeztu ; Programa Severo Ochoa del Principado de Asturias ; Thalis ; EU-ESF ; Greek NSRF ; Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University ; Welch Foundation ; Weston Havens Foundation (U.S.A.) ; Horizon 2020 Grant: 675440 ; FWO (Belgium) under the Excellence of Science -EOS: 30820817 ; Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences: 123842 ; Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences: 123959 ; Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences: 124845 ; Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences: 124850 ; Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences: 125105 ; European Union, Regional Development Fund: Harmonia 2014/14/M/ST2/00428 ; European Union, Regional Development Fund: 2014/13/B/ST2/02543 ; European Union, Regional Development Fund: 2014/15/B/ST2/03998 ; European Union, Regional Development Fund: 2015/19/B/ST2/02861 ; Sonata-bis: 2012/07/E/ST2/01406 ; Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de Maeztu: MDM-2015-0509 ; Welch Foundation: C-1845 ; Measurements of di ff erential cross sections for inclusive very forward jet production in proton-lead collisions as a function of jet energy are presented. The data were collected with the CMS experiment at the LHC in the laboratory pseudorapidity range 6 : 6 < < 5 : 2. Asymmetric beam energies of 4TeV for protons and 1.58TeV per nucleon for Pb nuclei were used, corresponding to a center-of-mass energy per nucleon pair of p sNN = 5 : 02TeV. Collisions with either the proton (p+ Pb) or the ion (Pb+ p) traveling towards the negative hemisphere are studied. The jet cross sections are unfolded to stable-particle level cross sections with pT & 3 GeV, and compared to predictions from various Monte Carlo event generators. In addition, the cross section ratio of p+ Pb and Pb+ p data is presented. The results are discussed in terms of the saturation of gluon densities at low fractional parton momenta. None of the models under consideration describes all the data over the full jet-energy range and for all beam con fi gurations. Discrepancies between the di ff erential cross sections in data and model predictions of more than two orders of magnitude are observed.