Measurements of the chiral magnetic effect with background isolation in 200 GeV Au+Au collisions at STAR

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F19%3A00502950" target="_blank" >RIV/61389005:_____/19:00502950 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.nuclphysa.2018.08.035" target="_blank" >https://doi.org/10.1016/j.nuclphysa.2018.08.035</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.nuclphysa.2018.08.035" target="_blank" >10.1016/j.nuclphysa.2018.08.035</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Measurements of the chiral magnetic effect with background isolation in 200 GeV Au+Au collisions at STAR

Popis výsledku v původním jazyce

Using two novel methods, pair invariant mass (m(inv)) and comparative measurements with respect to reaction plane (Psi(RP)) and participant plane (Psi(PP)), we isolate the possible chiral magnetic effect (CME) from backgrounds in 200 GeV Au+Au collisions at STAR. The invariant mass method identifies the resonance background contributions, coupled with the elliptic flow (v(2)), to the charge correlator CME observable (Delta gamma). At high mass (m(inv) > 1.5 GeV/c(2)) where resonance contribution is small, we obtain the average Delta gamma magnitude. In the low mass region (m(inv) < 1.5 GeV/c(2)), resonance peaks are observed in Delta gamma(m(inv)). An event shape engineering (ESE) method is used to model the background shape in m(inv) to extract the potential CME signal at low m(inv). In the comparative method, the Psi(RP) is assessed by spectator neutrons measured by the ZDCs, and the Psi(PP) by the 2nd-harmonic event plane measured by the TPC. The v(2) is stronger along Psi(PP) and weaker along Psi(RP), in contrast, the magnetic field, mainly from spectator protons, is weaker along Psi(PP) and stronger along Psi(RP). As a result, the Delta gamma measured with respect to Psi(RP) and Psi(PP) contain different amounts of CME and background, and can thus determine these two contributions. It is found that the possible CME signals with background isolation by these two novel methods are small, on the order of a few percent of the inclusive Delta gamma measurements.

Název v anglickém jazyce

Measurements of the chiral magnetic effect with background isolation in 200 GeV Au+Au collisions at STAR

Popis výsledku anglicky

Using two novel methods, pair invariant mass (m(inv)) and comparative measurements with respect to reaction plane (Psi(RP)) and participant plane (Psi(PP)), we isolate the possible chiral magnetic effect (CME) from backgrounds in 200 GeV Au+Au collisions at STAR. The invariant mass method identifies the resonance background contributions, coupled with the elliptic flow (v(2)), to the charge correlator CME observable (Delta gamma). At high mass (m(inv) > 1.5 GeV/c(2)) where resonance contribution is small, we obtain the average Delta gamma magnitude. In the low mass region (m(inv) < 1.5 GeV/c(2)), resonance peaks are observed in Delta gamma(m(inv)). An event shape engineering (ESE) method is used to model the background shape in m(inv) to extract the potential CME signal at low m(inv). In the comparative method, the Psi(RP) is assessed by spectator neutrons measured by the ZDCs, and the Psi(PP) by the 2nd-harmonic event plane measured by the TPC. The v(2) is stronger along Psi(PP) and weaker along Psi(RP), in contrast, the magnetic field, mainly from spectator protons, is weaker along Psi(PP) and stronger along Psi(RP). As a result, the Delta gamma measured with respect to Psi(RP) and Psi(PP) contain different amounts of CME and background, and can thus determine these two contributions. It is found that the possible CME signals with background isolation by these two novel methods are small, on the order of a few percent of the inclusive Delta gamma measurements.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10304 - Nuclear physics

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Nuclear Physics. A

ISSN

0375-9474

e-ISSN

—

Svazek periodika

982

Číslo periodika v rámci svazku

2

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

4

Strana od-do

535-538

Kód UT WoS článku

000457515500119

EID výsledku v databázi Scopus

2-s2.0-85060123771