First measurement of the forward rapidity gap distribution in pPb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV

Abstract

For the first time at LHC energies, the forward rapidity gap spectra from proton-lead collisions for both proton and lead dissociation processes are presented. The analysis is performed over 10.4 units of pseudorapidity at a center-of-mass energy per nucleon pair of $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV, almost 300 times higher than in previous measurements of diffractive production in proton-nucleus collisions. For lead dissociation processes, which correspond to the pomeron-lead event topology, the EPOS-LHC generator predictions are a factor of two below the data, but the model gives a reasonable description of the rapidity gap spectrum shape. For the pomeron-proton topology, the EPOS-LHC, QGSJET II, and HIJING predictions are all at least a factor of five lower than the data. The latter effect might be explained by a significant contribution of ultra-peripheral photoproduction events mimicking the signature of diffractive processes. These data may be of significant help in understanding the high energy limit of quantum chromodynamics and for modeling cosmic ray air showers.

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-18-019 (CMS Public Pages)

References in corpus (7)

• Particle-flow reconstruction and global event description with the CMS detector
• The CMS trigger system
• Description and performance of track and primary-vertex reconstruction with the CMS tracker
• The Physics of Ultraperipheral Collisions at the LHC
• Hadron production in p+p, p+Pb, and Pb+Pb collisions with the HIJING 2.0 model at energies available at the CERN Large Hadron Collider
• Measurement of diffraction dissociation cross sections in pp collisions at sqrt(s) = 7 TeV
• Performance of the CMS Zero Degree Calorimeters in pPb collisions at the LHC

Cited by in corpus (1)

• Constraining models of hadronic showers using proton-Oxygen collisions at the LHC involving proton/neutron tagging