# Quark Matter 2017

5-11 February 2017
Hyatt Regency Chicago
America/Chicago timezone

## Interplay of partonic collectivity and energy loss in understanding the Nuclear Modification factors

Not scheduled
2h 30m
Hyatt Regency Chicago

#### Hyatt Regency Chicago

151 East Wacker Drive Chicago, Illinois, USA, 60601
Board: C16
Poster

### Speaker

Tapan Nayak (Department of Atomic Energy (IN))

### Description

Nuclear modification factors ($R_{AA}$ or $R_{CP}$) of charged hadrons and
identified particles for heavy-ion
collisions at RHIC and LHC have been used to quantitatively study
the interplay of the partonic collectivity and hadronic
suppression. The outward pressure of strongly interacting partonic
medium in the early stage of the collision creates radial boost, which
is the key factor for Cronin-like peak structures. The structure could
be understood and unified in terms of ratio of particle species and
their mass dependence at a particular collision energy. The response
of the medium in the high $p_T$ region is same for all charged
particle species at a given collision energy, but the suppression
increases with increasing energy.
The primary goal of the present work is to understand the underlying
physics and disentangle the major
factors contributing to the shape of the nuclear modification
factors. A new observable, Integrated Suppression
Fraction (ISF) defined as the normalized area of the $R_{AA}$ structures
within a given $p_T$ window, has been introduced. ISF for
an intermediate $p_T$ window plotted as a function of collision energy
shows an increasing trend for RHIC energies with saturation at LHC
energies. This provides a prediction for $(R_{AA})$ for
the upcoming $Pb-Pb$ run for $\sqrt{s_{\rm NN}}=5.02$ TeV. A detailed
study of the ISF provides a novel method to understand the role of
collectivity and energy loss at these energies. Results for ISF
from the avalable experimental data will be presented and compared to
the expected energy loss properties from various theoretical models and event generators from different approaches, such as EPOS, Therminator as hydro-like collective models and also microscopic transport
models like UrQMD and AMPT.

Preferred Track Jets and High pT Hadrons Not applicable

### Primary author

Tapan Nayak (Department of Atomic Energy (IN))

### Presentation materials

There are no materials yet.