Two-particle azimuthal correlations in γp interactions using pPb collisions at √sNN = 8.16 TeV


Date

2023-09-10

Publication Type

Journal Article

ETH Bibliography

yes

Citations

Altmetric

Data

Abstract

The first measurements of the Fourier coefficients (V_n∆) of the azimuthal distributions of charged hadrons emitted from photon-proton (γp) interactions are presented. The data are extracted from 68.8 nb⁻¹ of ultra-peripheral proton-lead (pPb) collisions at √sNN=8.16TeV using the CMS detector. The high energy lead ions produce a flux of photons that can interact with the oncoming proton. This γp system provides a set of unique initial conditions with multiplicity lower than in photon-lead collisions but comparable to recent electron-positron and electron-proton data. The V_N∆ coefficients are presented in ranges of event multiplicity and transverse momentum (p_T) and are compared to corresponding hadronic minimum bias pPb results. For a given multiplicity range, the mean p_T of charged particles is smaller in γp than in pPb collisions. For both the γp and pPb samples, V_1∆ is negative, V_2∆ is positive, and V_3∆ consistent with 0. For each multiplicity and p_T range, V_2∆ is larger for γp events. The γp data are consistent with model predictions that have no collective effects.

Publication status

published

Editor

Book title

Volume

844

Pages / Article No.

137905

Publisher

Elsevier

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

CMS; Photon-proton; Collectivity

Organisational unit

03904 - Wallny, Rainer / Wallny, Rainer check_circle
03593 - Dissertori, Günther / Dissertori, Günther check_circle
09720 - de Cosa, Annapaola / de Cosa, Annapaola check_circle

Notes

Funding

758316 - Majorana neutrino discovery strategy with CMS (EC)

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