Azimuthal Correlations within Exclusive Dijets with Large Momentum Transfer in Photon-Lead Collisions
Physical Review Letters 2023
Viesturs Veckalns, CMS Collaboration

The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at s NN = 5.02 TeV , corresponding to an integrated luminosity of 0.38 nb - 1 , collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet transverse momentum vectors is found to be positive, and rising, as the dijet transverse momentum increases. A well-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects.


DOI
10.1103/PhysRevLett.131.051901
Hyperlink
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.051901

The CMS Collaboration, A.Tumasyan, W.Adam, V.Veckalns ... [et al.]. Azimuthal Correlations within Exclusive Dijets with Large Momentum Transfer in Photon-Lead Collisions. Physical Review Letters, 2023, Vol. 131, No. 5, Article number 051901. ISSN 0031-9007. e-ISSN 1079-7114. Available from: doi:10.1103/PhysRevLett.131.051901

Publication language
English (en)
The Scientific Library of the Riga Technical University.
E-mail: uzzinas@rtu.lv; Phone: +371 28399196