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Title: Kinematic bias on centrality selection of jet events in pPb collisions at the LHC

Centrality selection has been observed to have a large effect on jet observables in pPb collisions at the Large Hadron Collider, stronger than that predicted by the nuclear modification of parton densities. Here, we study to which extent simple considerations of energy–momentum conservation which link the hard process with the underlying event that provides the centrality estimator, affect jets observables in such collisions. We develop a simplistic approach that considers first the production of jets in a pp collision as described by PYTHIA. From each pp collision, the value of the energy of the parton from the proton participating in the hard scattering is extracted. Then, the underlying event is generated simulating a pPb collision through HIJING, but with the energy of the proton decreased according to the value extracted in the previous step, and both collisions are added. This model is able to capture the bulk of the centrality effect for central to semicentral collisions, for the two available sets of data: dijets from the CMS Collaboration and single jets from the ATLAS Collaboration. As expected, the model fails for peripheral collisions where very few nucleons from Pb participate.
Authors:
 [1] ;  [2] ; ORCiD logo [3]
  1. Univ. de Santiago de Compostela (Spain). Departmento de Fisica de Particulas and IGFAE
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Lab. for Nuclear Science and Dept. of Physics
  3. Univ. de Lisboa (Portugal). CENTRA; European Organization for Nuclear Research (CERN), Geneva (Switzerland). Physics Dept.
Publication Date:
Grant/Contract Number:
SC0011088
Type:
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 747; Journal Issue: C; Journal ID: ISSN 0370-2693
Publisher:
Elsevier
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
OSTI Identifier:
1228390
Alternate Identifier(s):
OSTI ID: 1455437