arXiv subjects

Supriya Das

Publications and source records attributed to Supriya Das.

16 recordsLinked to original sources

arXiv2025

Forward-backward correlations: A probe to study dynamical fluctuations

The source of the fluctuations in the final state particles is the initial event-by-event fluctuation in energy density. Forward-Backward (F-B) correlation is one of the important probes to study such fluctuations. The results of F-B correlation are available in a wide range of energy, from STAR of RHIC to ALICE of LHC. It will be more interesting to study the dynamical fluctuation using F-B correlation at SIS100 energy too. In this study, an attempt has been made to investigate the F-B correlation in UrQMD-hydro generated data for 10 AGeV Au+Au collisions.

hep-ph↗

arXiv2025

Existence of dynamical fluctuation in AMPT generated data for Au+Au collisions at 10 AGeV

In this study, the intermittency behavior of emitted particles produced in heavy ion collisions has been studied using both modes (default $\&$ string melting) of A Multi Phase Transport (AMPT) model-generated data. We adopted one of the most conventional and successful techniques, the Scaled Factorial Moment (SFM) method, using Monte Carlo (MC) data for 10 AGeV Au+Au collisions in search of intermittency in the model-generated data. Our interest is to search for intermittency behavior of particles that leads to multiplicity fluctuations and that would reveal a phase transition from hadronic matter to QGP. In this article, the intermittency values for both modes of AMPT data are presented. The results obtain some insight into the dynamics of heavy ion collisions and the formation of QGP.

hep-ph↗

arXiv2023

Jet modification in absence of QGP-medium: the role of multiparton interactions and color reconnection

Recent studies of high-multiplicity events in small collision systems (proton-proton and proton-lead) have drawn research interest towards the possibility of the formation of partonic medium in such systems. One of the important consequences of the formation of dense partonic medium is quenching of high-momentum final-state particles resulting in several experimental observations such as suppression in nuclear modification factor $R_{\rm AA}$, modification of jet shape observable $ρ(r)$ and jet fragmentation ($z^{\rm ch}$) distributions, etc. In this work, we study $ρ(r)$ and $z^{\rm ch}$ for inclusive charged-particle jets in proton-proton (pp) collisions at $\sqrt{s}$~=~13~TeV using PYTHIA~8 Monash~2013 Monte Carlo simulation. We show that the color reconnection (CR) and multiparton interaction (MPI) mechanisms in PYTHIA~8 can lead to an increased rate of jet production. We also find that the mechanisms of MPI and CR and change in the gluonic contribution in high-multiplicity events result in significant modification of $ρ(r)$ and $z^{\rm ch}$ compared to those in minimum bias events for 10~$<p_{\rm T,\,jet}^{\rm ch}<$~20~GeV/$c$. We notice a direct connection of $\langle N_{\rm MPI}\rangle$ and gluonic contribution with the amount of modification in $ρ(r)$ -- the larger the number of MPIs and/or gluonic contribution, the larger the amount of modification of $ρ(r)$.

hep-ph↗

arXiv2022

Development of a water-based cooling system for the Muon Chamber detector system of the CBM experiment

A water-based cooling system is being investigated to meet the cooling requirement of the Gas Electron Multiplier (GEM) based Muon Chamber (MuCh) detector system of the Compressed Baryonic Matter (CBM) experiment at GSI, Germany. The system is based on circulating cold water through the channels inside an aluminium plate. The aluminium plate is attached to a GEM chamber. A feasibility study is conducted on one small and two real-size prototype cooling plates. A microcontroller based unit has been built and integrated into the system to achieve automatic control and monitoring of temperature on plate surface. The real-size prototypes have been used in a test beam experiment at the CERN SPS (Super Proton Synchrotron) with the lead beam on a lead target. A setup using three prototype modules has been prepared in the lab for testing in a simulated real life environment. This paper discusses the working principle, mechanical design, fabrication, and test results of the cooling prototypes in detail.

physics.ins-det↗

arXiv2021

Charged particle to photon ratio in heavy-ion collisions at RHIC: a different point of view

We report an alternative explanation of the variation of charged particle to photon ratio in Cu+Cu collisions and Au+Au collisions from 1.4 $\pm$ 0.1 to 1.2 $\pm$ 0.1 at $\sqrt{\it{s}_{\rm NN}}$ = 62.4 GeV and 200 GeV respectively in STAR experiment at RHIC. Based on the theoretical predictions and experimental results we argue that the additional contribution of direct photons at $\sqrt{\it{s}_{\rm NN}}$ = 200 GeV in both Cu+Cu and Au+Au collisions are improving the ratio $\frac{N_{ch}}{N_γ}$ to 1.2 $\pm$ 0.1 from 1.4 $\pm$ 0.1.

hep-ph↗

arXiv2020

Characterisation of an RPC prototype with moderate resistivity plates using tetrafluoroethane ($C_2H_2F_4$)

Keeping in mind the requirements of high rate capable, cost effective, large area detectors to be used in future high energy physics experiments, commercially available bakelite plates having moderate bulk resistivity are used to build an RPC module. The chamber is tested with cosmic rays in the avalanche mode using 100\% Tetrafluoroethane ($C_2H_2F_4$). Standard NIM electronics are used for this study. The efficiency, noise rate and time resolution are measured. The detailed method of measurement and the first test results are presented.

physics.ins-det↗

arXiv2019

Study of jet-medium interactions using jet shape observables in heavy ion collisions at LHC energies with JEWEL

Based on a pQCD inspired dynamical model of jet-medium interactions, Jewel, we have studied possible modifications to inclusive jet yields and a set of jet shape observables, namely, the fragmentation functions and radial momentum distributions when jets propagate through a deconfined partonic medium created in collisions of heavy nuclei at Large Hadron Collider (LHC) energies. Jets are reconstructed with anti-k T algorithm in the pseudorapidity range $|η_{\rm jet} | < 2.1$ for resolution parameter R= 0.2, 0.3 and 0.4. For background subtraction, a Jewel-compatible 4-Momenta subtraction technique (4MomSub) have been used. The modification of inclusive jet-yields in Pb-Pb collisions relative to proton-proton interactions, quantified by $R^{\rm jet}_{AA}$, are seen to be in reasonable agreement with ALICE, ATLAS and CMS data over a broad transverse momentum range. Jewel is able to capture the qualitative features of the modifications to the fragmentation functions and radial momentum distributions in data but not always quantitatively. This quantitative discrepancy may be related to the simplified treatment of recoil partons in the background model and partly due to background subtraction procedure itself. Nevertheless, observed modification of jet shape variables in Jewel corroborates the fact that in-medium fragmentation is harder and more collimated than the fragmentation in vacuum. We further observe that these modifications depend on the transverse momentum of jets and it seems that medium resolves the core structure of low momentum jets below 100 GeV/c at LHC energies.

hep-ph↗

arXiv2018

Investigating the radial flow like effects using identified triggered correlation in pp collisions at $\sqrt{s}$ = 7 TeV

An inclusive baryon to meson enhancement with increase in multiplicity has been observed in pp collisions at $\sqrt{s}$= 7 TeV. Such a striking feature of the data can be explained by approaches based on hydrodynamics and multi-parton interactions (MPI) coupled with color reconnection (CR) mechanism. In this paper, we investigate the multiplicity evolution of the charged particle yields associated with pions and protons selected from the intermediate $p_{T}$ region where the inclusive baryon to meson enhancement has been observed. The study has been peformed using EPOS 3 (hydrodynamics) and PYTHIA 8 (MPI with CR) event generators in pp collisions at 7 TeV. We find that the response of the individual pion and proton triggered correlation towards these two mechanisms is different and can be used to disentangle the effect of one from the other. The current study can, therefore, provide important insights on the origin of radial flow like effects in high multiplicity pp collisions at the LHC energies.

hep-ph↗

arXiv2017

Centrality dependence of chemical freeze-out parameters from net-proton and net-charge fluctuations using hadron resonance gas model

We estimate chemical freeze-out parameters in HRG and EVHRG model by fitting the experimental information of net-proton and net-charge fluctuations measured in Au + Au collisions by the STAR collaboration at RHIC. We observe that chemical freeze-out parameters obtained from lower and higher order fluctuations are though almost same for $\sqrt{s_{NN}} > 27$ GeV, tend to deviate from each other at lower $\sqrt{s_{NN}}$. Moreover, these separations increase with decrease of $\sqrt{s_{NN}}$ and for a fixed $\sqrt{s_{NN}}$ increase towards central collisions. Furthermore, we observe an approximate scaling behaviour of $(μ_B/T)/(μ_B/T)_{central}$ with $(N_{part})/(N_{part})_{central}$ for the parameters estimated from lower order fluctuations for 11.5 GeV $\le \sqrt{s_{NN}} \le$ 200 GeV. Scaling is violated for the parameters estimated from higher order fluctuations for $\sqrt{s_{NN}}= 11.5$ and 19.6 GeV. It is observed that the chemical freeze-out parameter, which can describe $σ^2/M$ of net-proton very well in all energies and centralities, can not describe the $sσ$ equally well and vice versa.

nucl-th↗

arXiv2015

Study of gain variation as a function of physical parameters of GEM foil

The ALICE experiment at LHC has planned to upgrade the TPC by replacing the MWPC with GEM based detecting elements to restrict the IBF to a tolerable value. However the variation of the gain as a function of physical parameters of industrially produced large size GEM foils is needed to be studied as a part of the QA procedure for the detector. The size of the electron avalanche and consequently the gain for GEM based detectors depend on the electric field distribution inside the holes. Geometry of a hole plays an important role in defining the electric field inside it. In this work we have studied the variation of the gain as a function of the hole diameters using Garfield++ simulation package.

physics.ins-det↗

arXiv2014

Fluctuations and correlations of conserved charges in an excluded volume hadron resonance gas model

We present temperature ($T$) and baryonic chemical potential ($μ_B$) dependence of higher order fluctuations and correlation between conserved charges in Excluded Volume Hadron Resonance Gas (EVHRG) model. Products of moments, such as ratio of variance to mean ($σ^2/M)$, product of skewness and standard deviation ($Sσ$), product of kurtosis and variance ($κσ^2$), for net-proton, net-kaon and net-charge have been evaluated on the phenomenologically determined freeze-out curve. Further, products of moments for net-proton and net-charge have been compared with the experimental data measured by STAR experiment. The dependence of the model result on the hadronic radius parameter has also been discussed.

hep-ph↗

arXiv2013

Entropy scaling from chaotically produced particles in p-p collisions at LHC energies

Scaling of information entropy obtained from chaotically produced particles in p-p collisions, has been shown to be valid up to the highest available collision energy at LHC. Results from Monte Carlo simulation model PYTHIA 6.135 have also been compared. Based on the two com- ponent model and collision energy dependence of the chaoticity, charged particle multiplicities at proposed higher collision energies have been predicted.

hep-ph↗

arXiv2012

Net Charge Fluctuations as a signal of QGP from Polyakov-Nambu-Jona-Lasinio model

We report the first model study of the net charge fluctuations in terms of D-measure within the framework of the Polyakov-Nambu-Jona-Lasinio model. Net charge fluctuation is estimated from the charge susceptibility evaluated using PNJL model. A parameterization of the freeze-out curve has been used to obtain D as a function of sqrt(s). We have discussed our results vis-a-vis recent experimental findings from ALICE collaboration.

hep-ph↗

arXiv2011

Entropy scaling and thermalization in hadron-hadron collisions at LHC

The recent LHC data have once more brought the issue of the formation of thermalized state of matter in hadron-hadron collisions into the forefront. In this letter, we have shown that the scaling of the information entropy of the chaotically produced particles is valid up to recently available data from p+p collisions at $\sqrt{s}$ = 2.36 TeV obtained by ALICE experiment. We predict that at the highest energies projected for LHC, almost all the particles will be produced chaotically, indicating that a collective behavior should be observed in hadronic collisions, as indicated by one of present authors quite some time ago.

hep-ph↗

arXiv2006

Fluctuation studies in STAR

Study of event by event fluctuations of thermodynamic quantities offer us more insight about the hot and dense matter created in the relativistic heavy ion collisions. In this review the recent results on these studies carried out by the STAR collaboration are presented.

nucl-ex↗

arXiv2005

Event by Event fluctuation in K/pi ratio at RHIC

We present the preliminary results from our analysis of event by event fluctuation in K/pi ratio in Au+Au collision at \sqrt s_{NN} = 200 GeV and at 62.4 GeV using STAR detector at RHIC. Two different methods have been used to extract the strength of dynamical fluctuation and the centrality dependence of that. The results from the study of energy and centrality dependence of the dynamical fluctuation are presented. From the excitation function it is seen that at two RHIC energies the measure of dynamical fluctuation is constant with values very close to that at 12.3 GeV at SPS. The dynamical fluctuation is found to be positive and decreasing with increasing centrality at RHIC. The results are compared with HIJING model calculation with jets. Results from HIJING are found to be very close to data from central collisions whereas it over predicts the data for peripheral events.

nucl-ex↗