Direct photon production in Pb-Pb collisions at root s(NN)=2.76 TeV

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F16%3A00458656" target="_blank" >RIV/61389005:_____/16:00458656 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/16:00458656 RIV/68407700:21340/16:00301034

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.physletb.2016.01.020" target="_blank" >http://dx.doi.org/10.1016/j.physletb.2016.01.020</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.physletb.2016.01.020" target="_blank" >10.1016/j.physletb.2016.01.020</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Direct photon production in Pb-Pb collisions at root s(NN)=2.76 TeV

Popis výsledku v původním jazyce

Direct photon production at mid-rapidity in Pb-Pb collisions at root s(NN) = 2.76 TeV was studied in the transverse momentum range 0.9 < p(T) < 14 GeV/c. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e(+)e(-) pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0-20%, 20-40%, and 40-80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for p(T) greater than or similar to 5 GeV/c. Direct photon spectra down to p(T) approximate to 1 GeV/c could be extracted for the 20-40% and 0-20% centrality classes. The significance of the direct photon signal for 0.9 < p(T) < 2.1 GeV/c is 2.6 sigma for the 0-20% class. The spectrum in this p(T) range and centrality class can be described by an exponential with an inverse slope parameter of (297 +/- 12(stat) +/- 41(syst)) MeV. State-of-the-art models for photon production in heavy-ion collisions agree with the data within uncertainties.

Název v anglickém jazyce

Direct photon production in Pb-Pb collisions at root s(NN)=2.76 TeV

Popis výsledku anglicky

Direct photon production at mid-rapidity in Pb-Pb collisions at root s(NN) = 2.76 TeV was studied in the transverse momentum range 0.9 < p(T) < 14 GeV/c. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e(+)e(-) pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0-20%, 20-40%, and 40-80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for p(T) greater than or similar to 5 GeV/c. Direct photon spectra down to p(T) approximate to 1 GeV/c could be extracted for the 20-40% and 0-20% centrality classes. The significance of the direct photon signal for 0.9 < p(T) < 2.1 GeV/c is 2.6 sigma for the 0-20% class. The spectrum in this p(T) range and centrality class can be described by an exponential with an inverse slope parameter of (297 +/- 12(stat) +/- 41(syst)) MeV. State-of-the-art models for photon production in heavy-ion collisions agree with the data within uncertainties.

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

BG - Jaderná, atomová a molekulová fyzika, urychlovače

OECD FORD obor

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Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název periodika

Physics Letters. B

ISSN

0370-2693

e-ISSN

—

Svazek periodika

754

Číslo periodika v rámci svazku

MAR

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

14

Strana od-do

235-248

Kód UT WoS článku

000369601000035

EID výsledku v databázi Scopus

2-s2.0-84955439406