Direct-photon production in in elastic and high-multiplicity proton-proton collisions at root s=13 TeV

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F25%3A00388905" target="_blank" >RIV/68407700:21340/25:00388905 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1016/j.physletb.2025.139645" target="_blank" >https://doi.org/10.1016/j.physletb.2025.139645</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.physletb.2025.139645" target="_blank" >10.1016/j.physletb.2025.139645</a>

Result language

angličtina

Original language name

Direct-photon production in in elastic and high-multiplicity proton-proton collisions at root s=13 TeV

Original language description

In this letter, we present the first measurement of direct photons at the transverse momentum of 1 < p(T) < 6 GeV/c at midrapidity in inelastic and high-multiplicity proton-proton collisions at a centre-of-mass energy of root s = 13 TeV. The fraction of virtual direct photons in the inclusive virtual photon spectrum is obtained from a fit to the dielectron invariant mass spectrum. In the limit of zero invariant mass, this fraction is equal to the relative contribution of real direct photons in the inclusive real photon spectrum. Contributions from decays of light-flavour neutral mesons are estimated using independent measurements in proton-proton collisions at the same energy and the same event class. For the first time at the LHC energies, a direct-photon signal is observed at low p(T) in both inelastic and high-multiplicity event classes, with a significance of 3.2 sigma and 1.9 sigma in terms of standard deviations, correspondingly. The yield of direct photons in inelastic pp collisions is compared to perturbative QCD calculations. The integrated photon yield is studied as a function of charged-particle multiplicity and is compared to the results from other experiments and theoretical calculations. The results show a significant increase of direct-photon yield with charged-particle multiplicity.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10303 - Particles and field physics

Project

<a href="/en/project/LM2023040" target="_blank" >LM2023040: Research infrastructure for experiments at CERN</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physics Letters B

ISSN

0370-2693

e-ISSN

1873-2445

Volume of the periodical

868

Issue of the periodical within the volume

139645

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

16

Pages from-to

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UT code for WoS article

001520818100003

EID of the result in the Scopus database

2-s2.0-105008771873