Speaker
Bedangadas Mohanty
(National Institute of Science Education and Research (IN))
Description
The primary goal in heavy ion collision (HIC) experiments is to characterise
the properties of the hot and dense strongly interacting matter produced after
the collision. A precise comparison between theoretical predictions and experimental
data helps to select one theoretical model over another. However, one of the
significant challenges in such endeavors is the ignorance of the initial condition
at the time of collision. The nuclei being extended objects, there are event by
event geometric fluctuations in addition to quantum fluctuations of the nuclear
wave function. The standard method of analyzing the collisions in bins of centrality
is only able to select events with the initial condition averaged over many possible
initial states.
In this work, we perform an additional binning in terms of total spectator neutrons
in an event. A Multi Phase Transport (AMPT) model has been used in our analysis.
We have used the left ($L$) going and right ($R$) going spectator neutrons to form the
observable $L+R$ that can be measured in experiments using Zero Degree Calorimeters (ZDC).
The spectator binning helps us to analyse rarer events whose property usually get masked
in the standard analysis with centrality bins. We find that in a given centrality bin, events
with different ellipticity can be selected with $L+R$ binning. This serves as a complementary
technique to $q_2$-binning to analyse intial event shape. The advantage in using spectators
is that they are never part of the fireball produced and hence are pristine carriers of the
initial state information. We find that the scaling relation between $v_2/\varepsilon_2$ and
$\left(1/S\right)dN_{ch}/d\eta$ obeyed by different centrality bins is broken by the $L+R$ bins,
instead the hydrodynamic response for both centrality as well as $L+R$ bins exhibit scaling
with the initial transverse dimension.
| On behalf of collaboration: | NONE |
|---|
Primary author
Sandeep Chatterjee
(Variable Energy Cyclotron Centre)
Co-authors
Bedangadas Mohanty
(National Institute of Science Education and Research (IN))
Md. Rihan Haque
(V)
Vipul Bairathi
(National Institute of Science Education and Research)
