Browsing by Author "Gauri Devi"

Now showing 1 - 9 of 9

A background for thermal photons in heavy ion collisions
(Elsevier B.V., 2025) Satya Ranjan Nayak; Gauri Devi; Bhartendu Kumar Singh
In this work, we present the transverse momentum spectra of prompt and decay photons in Au-Au collisions for sNN= 200 GeV, 62.4 GeV, 39 GeV, and 27 GeV. The major sources of the photons in Angantyr include hard processes, Parton showers, and resonance decay. The multiparton interactions and hadronic rescatterings significantly increase the photon yield. The model shows a good match with the available experimental data at high pT. The difference in yield at low pT suggests that Quark Gluon Plasma of Teff = 0.167 GeV/c in central Au-Au collision at 200 GeV is formed, the new effective temperature is less than the ones extracted without removing background photons. At low pT the decay photon spectra scales with ([Formula presented])1.25, the scaling is independent of collision energy and system size. The scaling no longer holds at high pT and the spectra become beam energy dependent. The scaled pT spectra of p-p and d-Au collisions show an opposite trend at high pT, their scaled yield is greater than the Au-Au collision at the same energy. © 2025 The Author(s)
DFT study of five-membered ring PAHs
(Elsevier Ltd, 2020) Gauri Devi; Mridusmita Buragohain; Amit Pathak
This work reports a ‘Density Functional Theory’ (DFT) calculation of PAH molecules with a five-member ring to determine the expected region of infrared features. It is highly possible that fullerene molecule might be originated from five-membered ring PAH molecules in the ISM. Effect of ionization and protonation on five-membered ring PAH molecule is also discussed. A detail vibrational analysis of five-membered ring PAH molecule has been reported to further compare with observations and to identify any observational counterpart. © 2018 Elsevier Ltd
DFT study of Interstellar PANH: Vibrational spectra of anionic and cationic variants
(Elsevier Ltd, 2022) Gauri Devi; Amit Pathak; Akant Vats
Polycyclic aromatic Hydrocarbons are present in the universe in varied forms and are extensively studied over the years to account for the complex natured Aromatic Infrared Bands (AIBs). As an abundant element in the interstellar medium, nitrogen may substitute carbon atoms in the aromatic rings of PAHs to form Polycyclic Aromatic Nitrogen Heterocyclic (PANH) molecules. These PANH molecules can have new emission features and may contribute to some of the AIBs. Extreme conditions of the ISM may support PAH and/or PANH molecules in the formation of their cationic or anionic forms to further explain the AIBs. The present work reports DFT study of PANH molecules and their ionized variants and discusses their IR spectroscopic features in the 6–10 μm region. © 2022
Higher flow harmonics of strange hadrons in Au+Au collisions at √sNN = 200 GeV and Pb+Pb collisions at √sNN = 2.76 TeV with HYDJET++ model
(Springer Science and Business Media Deutschland GmbH, 2023) Gauri Devi; Arpit Singh; Saraswati Pandey; B.K. Singh
Using the HYDJET++ model, we measure the higher-order flow harmonics vn (n = 2, 3, 4) of (multi-) strange hadrons in Au+Au collisions at sNN = 200 GeV and Pb+Pb collisions at sNN = 2.76 TeV. We have compared our model results with the available experimental data at RHIC and LHC energies. The model reproduces the higher flow harmonics of (multi-) strange hadrons as a function of pT , centrality, and quark content. We have studied and discussed mass ordering of flows vn (n = 2, 3, 4) among π++ π- , K-+ K+ , Ks0 , p+ p¯ , Λ + Λ ¯ , Ξ -+ Ξ ¯ + , and Ω -+ Ω ¯ + at low pT and the baryon-meson grouping at intermediate pT . We observe NCQ scaling in both RHIC as well as LHC energy regimes. Study of flow harmonics behaviour at RHIC and LHC energy regimes will provide an additional insight into the dynamics of anisotropic flow and the effect of radial flow expansion in the system. © 2023, The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature.
Higher harmonics of anisotropic flow at RHIC Beam Energy Scan energies
(Institute of Physics, 2025) Satya Ranjan Nayak; Gauri Devi; Akash Das; Bhartendu Kumar Singh
In this work, we report the HYDJET++ simulation results for the higher flow harmonics like elliptic flow (v 2), triangular flow (v 3), quadrangular flow (v 4), and pentangular flow (v 5) in Au-Au collisions at 200 GeV, 62.4 GeV, 39 GeV, 27 GeV, 19.6 GeV, and 14.5 GeV. The higher harmonics were calculated based on the eccentricities ϵ n and modulation in the rapidity profile ρ n of the fireball. These parameters were treated as related to the impact parameter. Both approaches describe the data with some qualitative differences. The ρ 3 modulations show a linear correlation with v 3 while the ϵ 3 show a non-linear trend. A background v 4 was observed due to v 2 in its reaction plane while no such background was observed in the symmetry plane of v 3, and no background effects were observed for v 5. The constant a 5, which defines the strength of the pentangular modulation at a given impact parameter, was found to be independent of beam energy, hence, we predicted the v 5 of charged hadrons for the remaining energies using . Finally, we have discussed the effect of these harmonics in the final state distribution of charged hadrons. © © 2025 EPLA. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
p T-spectra, nuclear modification factors (R AA, and R CP) of (multi-) strange hadrons in Au+Au collisions at s NN = 200 GeV with HYDJET++
(Institute of Physics, 2024) Gauri Devi; Arpit Singh; B.K. Singh
In this article, we have reported the transverse momentum (p T ) spectra and nuclear modification factors of (multi-) strange hadrons produced in Au+Au collisions at s NN = 200 GeV using the Monte Carlo HYDJET++ model. For the present study, we have tuned few of the input parameters, in both soft as well as hard parts, of the model to appropriately describe the production of (multi-) strange hadrons. We have presented the p T -spectra of (multi-) strange hadrons in different centrality intervals. On comparing p T -spectra with the experimental data, we observe that the model does not achieve thermal equilibrium for kaons toward peripheral collisions and for omega baryons for all the centrality intervals. The R AA results obtained by the model reproduce the experimental data well while the R CP results show less suppression at higher p T than the experimental data. Further, HYDJET++ results are also compared with different theoretical models and discussed, wherever possible. © 2024 IOP Publishing Ltd.
Production and enhancement of (multi-) strange hadrons in Au+Au collisions at sNN =200 GeV RHIC energy and Pb+Pb collisions at sNN =2.76 TeV LHC energy
(American Physical Society, 2023) Arpit Singh; P.K. Srivastava; Gauri Devi; B.K. Singh
In this article, we investigate Au+Au and Pb+Pb collision systems to understand the (multi-) strange hadron production at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies using the Monte Carlo HYDJET++ model. We study the pT spectra, particle ratios, and strangeness enhancement factor for (multi-) strange hadrons. The pT spectra of K+(K-), Ks0, Λ(Λ¯), Ξ-(Ξ¯+), and ω-(ω¯+) are shown for both Au+Au and Pb+Pb collision systems in various centrality intervals. We find that the strange quark thermalization might not be achieved by the model for multistrange baryons toward peripheral collisions. The pT-differential particle ratios, focused on strange hadron-to-meson ratios, are reported for 0-5% and 40-60% centrality intervals for both the collision systems. We observe an enhancement in the particle ratios at intermediate pT region. pT integrated strange-to-nonstrange ratios suggest that chemical equilibrium might not be achieved for multistrange hadrons. We report the strangeness enhancement factor for Λ(Λ¯), Ξ-(Ξ¯+), and ω-+ω¯+ at both RHIC and LHC energies. An increase in the enhancement factor is observed with the increase in strangeness content of the baryons. We also observe that enhancement is higher in Au+Au collisions than in Pb+Pb collisions. Further, we compare the HYDJET++ results with the experimental data and various other simulation models, wherever possible. © 2023 American Physical Society.
Production of multistrange hadrons in Pb+Pb collisions at energies available at the CERN Large Hadron Collider using the HYDJET++ model
(American Physical Society, 2025) Gauri Devi; Bhartendu Kumar Singh
For the present work, we have used the HYDJET++ model to explore the production of pure multi-strange hadrons in Pb+Pb collisions at √sNN = 2.76 TeV and √sNN = 5.02 TeV collision energies, respectively. We have performed simulations to investigate transverse momentum (pT) spectra and elliptic flow (v2) for φ mesons and Ωbaryons, and compared the results both with the ALICE experimental data and available model predictions for selected central classes. Furthermore, we have calculated the nuclear modification factors (RAA and RCP), which provide a perception of jet quenching phenomena. Hence, our findings enable the study of the energy and system dependence of φ and Ω hadrons production over a wide range of ultrarelativistic collision energies. We also present the particle ratios (Ω/φ, Ω+/Ω−, Ω/π, and φ/π), offering insights into the strangeness enhancement and chemical properties of the medium at both CERN Large Hadron Collider collision energies. Additionally, we also explore the predictions for the Ωbaryon in Pb+Pb collisions at √sNN = 5.02 TeV, focusing on RAA, RCP, and particle ratios within the HYDJET++ framework, offering insights into future measurements and particle dynamics in high-energy heavy-ion collisions. © (2025), (American Physical Society). All rights reserved.
Pseudorapidity window size dependence of multiplicity fluctuations in high-energy collisions with system size and beam energies
(World Scientific, 2022) Ashwini Kumar; Gauri Devi; B.K. Singh; Bushra Ali; Shakeel Ahmad
An investigation of the critical behavior of strongly interacting quantum chromodynamics (QCD) matter has been performed by analyzing fluctuation observables on event-by-event (ebe) basis measured in high-energy collision experiments. The fluctuation analysis is performed using nuclear interactions at different target sizes and at different colliding beam energies as a function of varying width of pseudorapidity interval. For the sake of comparison, ebe multiplicity fluctuations in hadronic and heavy ion collisions (p-H, p-A and A-B) are studied within the framework of the Lund Monte Carlo-based FRITIOF model. Charged particle multiplicity and the variance of the multiplicity distribution are estimated for the interactions involving different target sizes and beam momenta, i.e., p-H, p-CNO, p-AgBr at 200 A GeV/c and 16O-AgBr collisions at 14.6 A, 60 A and 200 A GeV/c. Further, multiplicity fluctuations are quantified in terms of intensive quantity, the scaled variances ω and the strongly intensive quantity ςFB derived from the charged particle multiplicity and the width of the multiplicity distribution. Strongly intensive quantity ςFB is a quantity of great significance to extract information about short-and long-range multiplicity correlations. Furthermore, the collision centrality and centrality bin width-dependent behavior of the multiplicity fluctuation have been examined in the framework of Lund Monte Carlo-based FRITIOF model. Results based on the fluctuation analysis carried out in this study are interpreted in terms of dynamics of collision process and the possibility of related QCD phase transition. © 2022 World Scientific Publishing Company.