Analysis of the apparent nuclear modification in peripheral Pb-Pb collisions at 5.02 TeV

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F19%3A00505689" target="_blank" >RIV/61389005:_____/19:00505689 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/19:00505689 RIV/68407700:21340/19:00333254

Výsledek na webu

<a href="https://doi.org/10.1016/j.physletb.2019.04.047" target="_blank" >https://doi.org/10.1016/j.physletb.2019.04.047</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.physletb.2019.04.047" target="_blank" >10.1016/j.physletb.2019.04.047</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Analysis of the apparent nuclear modification in peripheral Pb-Pb collisions at 5.02 TeV

Popis výsledku v původním jazyce

Charged-particle spectra at midrapidity are measured in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair root s(NN) = 5.02 TeV and presented in centrality classes ranging from most central (0-5%) to most peripheral (95-100%) collisions. Possible medium effects are quantified using the nuclear modification factor (R-AA) by comparing the measured spectra with those from proton-proton collisions, scaled by the number of independent nucleon-nucleon collisions obtained from a Glauber model. At large transverse momenta (8 < p(T) < 20 GeV/c), the average R-AA is found to increase from about 0.15 in 0-5% central to a maximum value of about 0.8 in 75-85% peripheral collisions, beyond which it falls off strongly to below 0.2 for the most peripheral collisions. Furthermore, R-AA initially exhibits a positive slope as a function of p(T) in the 8-20 GeV/c interval, while for collisions beyond the 80% class the slope is negative. To reduce uncertainties related to event selection and normalization, we also provide the ratio of R-AA in adjacent centrality intervals. Our results in peripheral collisions are consistent with a PYTHIA-based model without nuclear modification, demonstrating that biases caused by the event selection and collision geometry can lead to the apparent suppression in peripheral collisions. This explains the unintuitive observation that R-AA is below unity in peripheral Pb-Pb, but equal to unity in minimum-bias p-Pb collisions despite similar charged-particle multiplicities.

Název v anglickém jazyce

Analysis of the apparent nuclear modification in peripheral Pb-Pb collisions at 5.02 TeV

Popis výsledku anglicky

Charged-particle spectra at midrapidity are measured in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair root s(NN) = 5.02 TeV and presented in centrality classes ranging from most central (0-5%) to most peripheral (95-100%) collisions. Possible medium effects are quantified using the nuclear modification factor (R-AA) by comparing the measured spectra with those from proton-proton collisions, scaled by the number of independent nucleon-nucleon collisions obtained from a Glauber model. At large transverse momenta (8 < p(T) < 20 GeV/c), the average R-AA is found to increase from about 0.15 in 0-5% central to a maximum value of about 0.8 in 75-85% peripheral collisions, beyond which it falls off strongly to below 0.2 for the most peripheral collisions. Furthermore, R-AA initially exhibits a positive slope as a function of p(T) in the 8-20 GeV/c interval, while for collisions beyond the 80% class the slope is negative. To reduce uncertainties related to event selection and normalization, we also provide the ratio of R-AA in adjacent centrality intervals. Our results in peripheral collisions are consistent with a PYTHIA-based model without nuclear modification, demonstrating that biases caused by the event selection and collision geometry can lead to the apparent suppression in peripheral collisions. This explains the unintuitive observation that R-AA is below unity in peripheral Pb-Pb, but equal to unity in minimum-bias p-Pb collisions despite similar charged-particle multiplicities.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10304 - Nuclear physics

Projekt

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

Návaznosti

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

Rok uplatnění

2019

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

793

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

13

Strana od-do

420-432

Kód UT WoS článku

000470064800063

EID výsledku v databázi Scopus

2-s2.0-85065671184