Speaker
Hongyan Yang
(University of Utrecht (NL))
Description
Correlated unlike sign dielectrons provide important and relatively clean information to access the properties of the hot and dense matter, the Quark-Gluon Plasma (QGP), created in relativistic heavy-ion collisions. Once they are produced, they traverse the fireball without interacting strongly with the medium. The collective behaviour of the dielectrons with respect to a global event plane provides rich information of the initial stage of the expanding fireball where flow starts developing.
In the central barrel ($|\eta|<0.8$) of the ALICE experiment, electrons (and positrons) can be detected and identified by the Inner Tracking System, the Time Projection Chamber and the Time-Of-Flight. For the study of the dielectron elliptic flow at mid-rapidity, the VZERO scintillators at forward rapidity are used for event plane estimation to avoid auto-correlations.
In this poster, a first attempt to measure the elliptic flow of dielectrons in Pb--Pb collisions at $\sqrt{s_{\mathrm {NN}}} = 2.76$ TeV with the ALICE experiment is presented. An effort is put into removing the background $v_2$ from uncorrelated unlike sign dielectrons with the mixed-event approach. A comparison to the elliptic flow of identified particles measured in the same system, as well as measurements from experiments at RHIC will be discussed. This work is expected to be the first step towards the measurement of the elliptic flow of thermal photons radiated from the fireball, which is regarded as a unique probe to study the formation time of the QGP.
| On behalf of collaboration: | ALICE |
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Primary author
Hongyan Yang
(University of Utrecht (NL))
