ELFT HÍRADÓ

[Ferenc Siklér <sikler.ferenc AT wigner.hu>]

Kedves kollégák,

 Meghívunk minden érdeklődőt a Wigner FK Nagyenergiás Fizikai Osztályának jövő 
hétfői szemináriumára, május 30., 14:00-ra [speciális időpont].

 Részletek itt, absztrakt alább:
 https://indico.wigner.hu/event/1389/

 [Az előadás a zoom-on keresztül is követhető, csatlakozási infók a fenti 
leírásban.]

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Ashik Ikbal Sheikh (Department of Physics, Kent State University)

Measurement of electric charge dependent splitting of directed flow in STAR 
experiment at RHIC

Abstract: Strong electromagnetic fields produced in the early stages of 
heavy-ion collisions can lead to splitting of the rapidity-odd directed flow 
(v1) of positive and negative hadrons. However, the interpretation of such 
measurements with light hadrons is complicated by the low magnitude of directed 
flow at mid-rapidity or higher beam energy, as well as by ambiguities arising 
from transported quarks (u, d). In order to avoid such complications, we focus 
on the particle species where all constituent quarks are produced (u¯, ¯d, s, 
s¯), as opposed to possibly transported, and demonstrate using a novel analysis 
method that the coalescence sum rule holds for hadrons with identical quark 
content. We examine the coalescence sum rule as a function of rapidity for 
non-identical quark content having the same/similar mass at constituent level 
but different electric charge (∆q) and strangeness (∆S). The difference in 
the directed flow of different quark and anti-quark combinations, e.g., 
v1(Ω−(sss)) − v1(Ω¯ +(¯ss¯s¯)), is a measure of coalescence sum rule 
violation, and we call it directed flow splitting (∆v1) between quarks and 
anti-quarks. First we measure v1 as a function of rapidity; and then we 
estimate ∆q and ∆S dependence of the ∆v1-slope (d∆v1/dy) between produced 
quarks and anti-quarks in Au+Au collisions at √sNN = 27 GeV and 200 GeV. The 
d∆v1/dy increases when ∆q and ∆S increase. This d∆v1/dy signal becomes 
stronger going from collision energy √sNN = 200 GeV to 27 GeV. We compare our 
measurements with the Parton-Hadron String Dynamics (PHSD) model calculations 
including electromagnetic field.

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Üdvözlettel,
 Siklér Ferenc