Dielectron production at midrapidity at low transverse momentum in peripheral and semi-peripheral Pb-Pb collisions at root s(NN)=5.02 TeV

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21340%2F23%3A00367693" target="_blank" >RIV/68407700:21340/23:00367693 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.1007/JHEP06(2023)024" target="_blank" >https://doi.org/10.1007/JHEP06(2023)024</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/JHEP06(2023)024" target="_blank" >10.1007/JHEP06(2023)024</a>

Result language

angličtina

Original language name

Dielectron production at midrapidity at low transverse momentum in peripheral and semi-peripheral Pb-Pb collisions at root s(NN)=5.02 TeV

Original language description

The first measurement of the e(+)e(-) pair production at low lepton pair transverse momentum (p(T,ee)) and low invariant mass (m(ee)) in non-central Pb-Pb collisions at root s(NN) = 5.02TeV at the LHC is presented. The dielectron production is studied with the ALICE detector at midrapidity (vertical bar eta(e)vertical bar < 0.8) as a function of invariant mass (0.4 <= m(ee) < 2.7 GeV/c(2)) in the 50-70% and 70-90% centrality classes for p(T,ee) < 0.1 GeV/c, and as a function of p(T,ee) in three m(ee) intervals in the most peripheral Pb-Pb collisions. Below a p(T,ee) of 0.1 GeV/c, a clear excess of e(+)e(-) pairs is found compared to the expectations from known hadronic sources and predictions of thermal radiation from the medium. The m(ee) excess spectra are reproduced, within uncertainties, by different predictions of the photon-photon production of dielectrons, where the photons originate from the extremely strong electromagnetic fields generated by the highly Lorentz-contracted Pb nuclei. Lowest-order quantum electrodynamic (QED) calculations, as well as a model that takes into account the impact-parameter dependence of the average transverse momentum of the photons, also provide a good description of the p(T,ee) spectra. The measured root < p(T,ee)(2)> of the excess p(T,ee) spectrum in peripheral Pb-Pb collisions is found to be comparable to the values observed previously at RHIC in a similar phase-space region.

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

10301 - Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)

Project

<a href="/en/project/LM2018104" target="_blank" >LM2018104: Research Infrastructure for experiments at CERN</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach

Publication year

2023

Confidentiality

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

Name of the periodical

Journal of High Energy Physics

ISSN

1029-8479

e-ISSN

1029-8479

Volume of the periodical

2023

Issue of the periodical within the volume

6

Country of publishing house

DE - GERMANY

Number of pages

32

Pages from-to

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UT code for WoS article

001023417500001

EID of the result in the Scopus database

2-s2.0-85163101135