arXiv subjects

Bedangadas Mohanty

Publications and source records attributed to Bedangadas Mohanty.

At least 19 recordsLinked to original sources

arXiv2026

Experiment $\leftrightarrow$ lattice QCD: understanding high-temperature QCD matter

Relativistic heavy-ion collisions provide a unique experimental opportunity to study strongly interacting matter at extreme temperature and density, while lattice quantum chromodynamics (QCD) offers a first-principles approach to the equilibrium properties of such matter in the non-perturbative regime. The interplay between experiment and lattice QCD has therefore become central to establishing the properties and phase structure of QCD matter. Selected areas where this connection is particularly informative are discussed, including the QCD equation of state and its role in hydrodynamic descriptions of heavy-ion collisions, transport properties of the quark-gluon plasma, conserved-charge fluctuations and their relation to experimental cumulants, and the ongoing search for a critical point in the QCD phase diagram. Particular attention is given to the limitations involved in confronting equilibrium lattice calculations with the finite, dynamical and experimentally constrained systems produced in heavy-ion collisions. Recent developments increasingly allow quantitative tests of QCD thermodynamics over an extended range of temperature and baryon chemical potential. The continuing experimental programmes at RHIC and the LHC, together with future measurements at FAIR, NICA and the Electron-Ion Collider, provide important opportunities for an increasingly close interplay between lattice QCD, phenomenology and experiment.

hep-lat↗

arXiv2026

Collective excitations in the hot QCD medium and the propagation of Heavy Quarks

This review explores the current understanding of collective excitations and the dynamics of heavy quark propagation in the quark-gluon plasma (QGP) formed in relativistic heavy-ion collisions. We focus on three core aspects: the theoretical modelling of the QGP, including momentum anisotropy, medium-induced collisions, finite chemical potential, and non-ideal interactions; the collective behaviours within the plasma; and the interaction dynamics of heavy quarks as they traverse the medium. Along with the polarization energy loss mechanisms, we also review the possibility of energy gain due to thermal field fluctuations. Lastly, we discuss how these theoretical insights can be tested through experiments and outline possible directions for future research.

nucl-th↗

arXiv2026

Finite-size behavior of higher-order cumulant ratios near criticality in two-dimensional Potts models

Theoretical considerations predict a specific hierarchy among ratios of net-baryon number cumulants ($χ_n$, where $n$ is the order of cumulant) in the vicinity of the transition from the low-temperature hadronic phase to the high temperature quark-gluon plasma phase at small baryon chemical potential, $μ_\mathrm{B}$, in the QCD phase diagram. This hierarchy, $\frac{χ_6}{χ_2} < \frac{χ_5}{χ_1} < \frac{χ_4}{χ_2} < \frac{χ_3}{χ_1}$, has been observed by the STAR experiment in net-proton number (a proxy of net-baryon number) cumulant ratios over a broad range of collision energies. Motivated by these findings, we investigate whether similar ordering emerges generically in finite statistical systems undergoing second-order phase transitions. We employ two different spin models: the two-state and three-state Potts models in two dimensions, both exhibiting a transition from an ordered phase to a disordered phase at their respective critical temperatures. Monte Carlo simulations are performed on square lattices of varying sizes using the Wolff cluster algorithm. Cumulants of the total magnetization are calculated up to sixth order in both of these models in a temperature range near their corresponding critical temperatures. Higher-order cumulants exhibit extrema (peaks/troughs) whose magnitudes grow with both cumulant order and lattice size, reflecting enhanced critical fluctuations. Except within a narrow temperature window above the critical temperature, neither the complete hierarchy nor its exact reverse is realized over the studied temperature range in either model.

hep-lat↗

arXiv2026

Light-Flavour Resonance Production in High-Energy Heavy-Ion Collisions: An Experimental Review

Resonances provide sensitivity to the late-stage dynamics of heavy-ion collisions, as their lifetimes are comparable to the duration of the hadronic phase. This review summarizes state-of-the-art measurements of light-flavour mesonic and baryonic resonances, including $ρ$(770), $K^{\star}$(892), $ϕ$(1020), $Δ$(1232), $Λ^{\star}$(1520), $Σ^{\star}$(1385) and $Ξ^\star$(1530), in pp, p-A and A-A collisions at SPS, RHIC and the LHC. Systematic trends in yields, mass and width modifications, transverse-momentum spectra, nuclear modification factors, and particle ratios reveal the interplay of re-scattering and regeneration, medium-induced suppression, and the development of collective dynamics with increasing system size and multiplicity. Anisotropic flow results confirm the coupling of resonances to the expanding medium, while recent vector-meson spin-alignment measurements offer fresh insights into hadronization mechanisms and local fields. Ultra-peripheral collisions provide vacuum-like baselines for isolating in-medium effects. Emerging opportunities for charm-resonance studies in upcoming high-luminosity experiments are also outlined.Together, these advances demonstrate the important role of resonance measurements in constraining the space-time evolution of strongly interacting matter.

nucl-ex↗

arXiv2025

Study of $p_\mathrm{T}$-differential radial flow in blast-wave model

The transverse momentum-differential radial flow observable $v_0(p_\mathrm{T})$, recently proposed and measured by the ATLAS and ALICE collaborations, provides a novel tool to probe radial expansion dynamics in high-energy heavy-ion collisions. In this work, we conduct a detailed study of $v_0(p_\mathrm{T})$ using a blast-wave model that incorporates hydrodynamic-like expansion and thermal emission. We introduce event-by-event fluctuations in the transverse expansion velocity and kinetic freeze-out temperature using Gaussian probability distributions. Our results show that increasing the mean expansion velocity leads to a clear mass ordering in $v_0(p_\mathrm{T})$, while fluctuations in both expansion velocity and freeze-out temperature significantly enhance the magnitude of $v_0(p_\mathrm{T})$, particularly at higher $p_\mathrm{T}$. We fit blast-wave model calculations for identified hadrons ($π$, K, and p) to recent ALICE data from Pb--Pb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV using a Bayesian parameter estimation framework. The extracted mean transverse expansion velocity decreases, while the kinetic freeze-out temperature increases, from central to peripheral collisions. Additionally, the freeze-out temperatures inferred from $v_0(p_\mathrm{T})$ are systematically higher than those obtained from conventional $p_\mathrm{T}$-spectra fits, likely due to the reduced sensitivity of $v_0(p_\mathrm{T})$ to resonance decay contributions.

nucl-ex↗

arXiv2025

Measurement of cosmic muon-induced events in an HPGe detector using time-coincidence technique

Detailed understanding and suppression of backgrounds are among the key challenges faced by Coherent Elastic Neutrino-Nucleus Scattering (CE\ensuremathνNS) experiments. The sensitivity of these experiments is largely determined by the background levels arising from various sources. Above-ground and shallow-overburden neutrino experiments typically employ passive shielding, primarily composed of lead (Pb), to suppress environmental $γ$ background. However, such shielding can introduce additional backgrounds that are particularly challenging for CE\ensuremathνNS experiments. These backgrounds arise mainly from $γ$ and neutrons produced by cosmic muon interactions in the shielding, and their contribution can become significant depending on the amount of Pb shielding used. In the current work, we measure the yield of secondary particles originating from Pb as a result of high-energy cosmic muon interaction, using a high-purity germanium (HPGe) detector and plastic scintillators. A time-coincidence technique is used to identify and reject these secondary background events from the experimental data. The obtained mean characteristic time of these residual background events is 11 $\pm$ 4 $μ$s, which is consistent with the Geant4-based MC simulation result of 11 $\pm$ 1 $μ$s. The measured efficiency-corrected rate of muon-induced events in the HPGe detector is 34 $\pm$ 1 (stat.) $\pm$ 3 (sys.) day$^{-1}$kg$^{-1}$ within the energy range of 30 keV to 2000 keV. The yield of muon-induced secondary backgrounds in 10 cm thick Pb shielding is evaluated to be $(11 \pm 1 (\text{stat.}) \pm 1 (\text{sys.}))$ secondary events$\thinspace\text{kg}^{-1}\thinspace\mathrm{m^{-2}}\thinspace\text{muon}^{-1}$ at sea level.

physics.ins-det↗

arXiv2022

Global constraint on the magnitude of anomalous chiral effects in heavy-ion collisions

When searching for anomalous chiral effects in heavy-ion collisions, one of the most crucial points is the relationship between the signal and the background. In this letter, we present a simulation in a modified blast wave model at LHC energy, which can simultaneously characterize the majority of measurable quantities, in particular, the chiral magnetic effect (CME) and the chiral magnetic wave (CMW) observables. Such a universal description, for the first time, naturally and quantitatively unifies the CME and the CMW studies and brings to light the connection with the local charge conservation (LCC) background. Moreover, a simple phenomenological approach is performed to introduce the signals, aiming at quantifying the maximum allowable strength of the signals within experimental precision. Such a constraint provides a novel perspective to understand the experimental data and sheds new light on the study of anomalous chiral effects as well as charge dependent correlations.

nucl-th↗

arXiv2022

A Search for Low-mass Dark Matter via Bremsstrahlung Radiation and the Migdal Effect in SuperCDMS

In this paper, we present a re-analysis of SuperCDMS data using a profile likelihood approach to search for sub-GeV dark matter particles (DM) through two inelastic scattering channels: bremsstrahlung radiation and the Migdal effect. By considering possible inelastic scattering channels, experimental sensitivity can be extended to DM masses that would otherwise be undetectable through the DM-nucleon elastic scattering channel, given the energy threshold of current experiments. We exclude DM masses down to $220~\textrm{MeV}/c^2$ at $2.7 \times 10^{-30}~\textrm{cm}^2$ via the bremsstrahlung channel. The Migdal channel search excludes DM masses down to $30~\textrm{MeV}/c^2$ at $5.0 \times 10^{-30}~\textrm{cm}^2$.

hep-ex↗

arXiv2021

Spin alignment measurement of vector mesons produced in high energy collisions

This review covers the recent experimental development on spin alignment measurements of $K^{*0}$ and $ϕ$ vector mesons in heavy-ion and pp collisions at RHIC and LHC energies. Measurements in $e^+e^-$ collisions at LEP energies are also discussed. Spin alignment of vector mesons are studied by measuring the second diagonal element $ρ_{00}$ of spin density matrix. The $ρ_{00}$ is obtained by measuring the angular distribution of vector meson decay daughter with respect to the quantization axis in vector meson rest frame. Measured $ρ_{00}$ values for vector mesons are found to be larger than 1/3 at high momentum in $e^+e^-$ collisions at LEP energies, suggesting the preferential production of vector meson with helicity zero state from the fragmentation process. The $ρ_{00}$ values are found to be smaller than 1/3 ($ρ_{00}$ = 1/3 implies no spin alignment) for $K^{*0}$ and $ϕ$ vector mesons at low transverse momentum in Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV. This observations are qualitatively consistent with the expectation from models which attribute the spin alignment effect due to polarization of quarks in the presence of large initial angular momentum in non-central heavy-ion collisions and its subsequent hadronization by the process of recombination. No significant spin alignment effect is observed for $K^0_S$ (spin = 0) in mid-central Pb--Pb collisions and for vector mesons in pp collisions. However, the preliminary results of $ρ_{00}$ for $ϕ$ mesons are larger than 1/3 at intermediate $p_{\mathrm{T}}$ in Au--Au collisions at RHIC energies and can be attributed to the presence of $ϕ$ meson field. Although there is evidence of spin alignment effect of vector mesons in heavy-ion collisions but the measured effect is surprisingly larger in context of hyperon polarization. Therefore these results will trigger further theoretical study.

nucl-ex↗

arXiv2021

Multiplicity dependence freeze-out scenarios in pp collisions at $\sqrt{s}$ = 7 TeV

The data on transverse momentum integrated hadron yields in different multiplicity classes of p+p collisions at $\sqrt{s}=7$ TeV have been analyzed to extract the chemical freeze-out parameters using a thermal model. The chemical freeze-out parameters have been extracted for three different freeze-out schemes: i. unified freeze-out for all hadrons in complete thermal equilibrium (1CFO), ii. unified freeze-out for all hadrons with an additional parameter $γ_S$ which accounts for possible out-of-equilibrium production of strange hadrons (1CFO$+γ_S$), and iii. separate freeze-out for hadrons with and without strangeness content (2CFO). It has been observed that 1CFO$+γ_S$ scheme gives the best description of the hadronic yields at midrapidity when multiplicity ($\langle dN_{ch}/dη\rangle$) of the collision is less than 10. This indicates that the strangeness is out of equilibrium in most of the multiplicity classes of p+p collisions. All the three parameters of this CFO scheme, temperature ($T$), radius of the fireball ($R$) and strangeness suppression factor ($γ_S$) increase with the increase of $\langle dN_{ch}/dη\rangle$. Further, we have compared applicability of different CFO schemes considering two more colliding system p+Pb at $\sNN$ = 5.02 and Pb+Pb at $\sNN$ = 2.76 TeV along with p+p collisions at $\sqrt{s}=7$ TeV. We observe a freeze-out volume (or multiplicity) dependence of CFO schemes regardless of colliding ions. The 1CFO+$γ_S$, 1CFO and 2CFO schemes provide best description of the data when the dimension less quantity $VT^3$ approximately satisfies the conditions $VT^3 <50$, $50 < VT^3 < 100$ and $VT^3 > 100$ respectively or the corresponding multiplicity satisfies the conditions $\langle dN_{ch}/dη\rangle<30$, $30 < dN_{ch}/dη< 60$ and $\langle dN_{ch}/dη\rangle>100$ respectively.

hep-ph↗

arXiv2021

Probing the profile of bulk matter in p+Pb collisions via directed flow of heavy quarks

The asymmetric initial geometry in p+Pb collisions provide an opportunity to probe the initial matter distribution in these collisions. Using A Multi-Phase Transport (AMPT) model, we have studied the production of light and heavy quark particles in p+Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV. The pseudo-rapidity density (dN/d$η$) and elliptic flow ($v_{2}$) of light-quark particles from AMPT reasonably agrees with the measurements by ALICE. We predicted the directed flow of light and heavy quarks in p+Pb collisions. The $v_{1}$ of both light and heavy-quark mesons show a non-trivial $p_{T}$ dependence in p- and Pb-going directions. When integrated over the transverse momentum range 0 $ < p_{T} < $5 GeV/c, the magnitude of heavy quark directed flow ($v_{1}$) is found to be 15 times larger than the light quark species in the Pb-going direction while the same in the p-going direction are comparable. The light and heavy quarks $v_{1}$ may offer the possibility to probe the initial matter density as well as the collective dynamics in p+Pb collisions

hep-ph↗

arXiv2021

Centrality, transverse momentum and collision energy dependence of the Tsallis parameters in relativistic heavy-ion collisions

The thermodynamic properties of matter created in high-energy heavy-ion collisions have been studied in the framework of the non-extensive Tsallis statistics. The transverse momentum ($p_{\rm T}$)~spectra of identified charged particles (pions, kaons, protons) and all charged particles from the available experimental data of Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC) energies and Pb-Pb collisions at the Large Hadron Collider (LHC) energies are fitted by the Tsallis distribution. The fit parameters, $q$ and $T$ measure the degree of deviation from an equilibrium state and the effective temperature of the thermalized system, respectively. The $p_{\rm T}$~spectra are well described by the Tsallis distribution function from peripheral to central collisions for the wide range of collision energies, from $\sqrt{s_{\rm NN}}$ = 7.7 GeV to 5.02 TeV. The extracted Tsallis parameters are found to be dependent on the particle species, collision energy, centrality, and fitting ranges in $p_{\rm T}$. For central collisions, both $q$ and $T$ depend strongly on the fit ranges in $p_{\rm T}$. For most of the collision energies, $q$ remains almost constant as a function of centrality, whereas $T$ increases from peripheral to central collisions. For a given centrality, $q$ systematically increases as a function of collision energy whereas $T$ has a decreasing trend. A profile plot of $q$ and $T$ with respect to collision energy and centrality shows an anti-correlation between the two parameters.

hep-ph↗

arXiv2021

QCD Critical Point and High Baryon Density Matter

We report the latest results on the search for the QCD critical point in the QCD phase diagram through high energy heavy-ion collisions. The measurements discussed are based on the higher moments of the net-proton multiplicity distributions in heavy-ion collisions. A non-monotonic variation in the product of kurtosis times the variance of the net-proton distribution is observed as a function of the collision energy with 3$σ$ significance. We also discuss the results of the thermal model in explaining the measured particle yield ratios in heavy-ion collisions and comparison of the different variants of hardon resonance gas model calculation to the data on higher moments of net-proton distributions. We end with a note that the upcoming programs in high baryon density regime at various experimental facilities will complete the search for the QCD critical point through heavy-ion collisions.

nucl-ex↗

arXiv2021

Passage of heavy quarks through the fluctuating hot QCD medium

The change in the energy of the moving heavy (charm and bottom) quarks due to field fluctuations present in the hot QCD medium has been studied. A finite quark chemical potential has been considered while modeling the hot QCD medium counting the fact that the upcoming experimental facilities such as Anti-proton and Ion Research (FAIR) and Nuclotron-based Ion Collider fAcility (NICA) are expected to operate at finite baryon density and moderate temperature. The effective kinetic theory approach has been adopted where the collisions have been incorporated using the well defined collisional kernel, known as Bhatnagar-Gross-Krook (BGK). To incorporate the non-ideal equations of state (EoSs) effects/ medium interaction effects, an extended effective fugacity model has been adopted. The momentum dependence of the energy change due to fluctuation for the charm and bottom quark has been investigated at different values of collision frequency and chemical potential. The results are exciting as the heavy quarks are found to gain energy due to fluctuations while moving through the produced medium at finite chemical potential and collision frequency.

nucl-th↗

arXiv2020

Spin alignment measurements of vector mesons with ALICE at LHC

We present the measurements related to the spin alignment of $\mathrm{K^{*0}}$ and $\mathrmϕ$ vector mesons at mid-rapidity for Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 2.76 TeV using the ALICE detector at the LHC. The second diagonal spin density matrix element ($ρ_{00}$) is measured from the angular distribution of the decay daughters of the vector meson in the decay rest frame, with respect to the event plane and the production plane. The $ρ_{00}$ values are found to be less than 1/3 at low $p_{\mathrm{T}}$ ($<$ 2 GeV/$c$) for both vector mesons. The observed deviations from 1/3 are maximal for mid-central collisions at a level of 3$σ$ for $\mathrm{K^{*0}}$ and 2$σ$ for $\mathrmϕ$ mesons. As a control measurement the \rh~values were found to be consistent with 1/3, i.e., no significant spin alignment, for pp collisions with respect to the production plane. The results are qualitatively consistent with the expectation from a model that attributes the spin alignment to a polarization of quarks in the presence of large initial angular momentum and a subsequent hadronization by the process of recombination.

nucl-ex↗

arXiv2020

Little-Bang and Femto-Nova in Nucleus-Nucleus Collisions

We make a theoretical and experimental summary of the state-of-the-art status of hot and dense QCD matter studies on selected topics. We review the Beam Energy Scan program for the QCD phase diagram and present the current status of search for QCD Critical Point, particle production in high baryon density region, hypernuclei production, and global polarization effects in nucleus-nucleus collisions. The available experimental data in the strangeness sector suggests that a grand canonical approach in thermal model at high collision energy makes a transition to the canonical ensemble behavior at low energy. We further discuss future prospects of nuclear collisions to probe properties of baryon-rich matter. Creation of a quark-gluon plasma at high temperature and low baryon density has been called the "Little-Bang" and, analogously, a femtometer-scale explosion of baryon-rich matter at lower collision energy could be called the "Femto-Nova", which may possibly sustain substantial vorticity and magnetic field for non-head-on collisions.

hep-ph↗

arXiv2020

Freeze-out and thermalization in relativistic heavy ion collisions

High energy heavy-ion collisions in laboratory produce a form of matter that can test Quantum Chromodynamics (QCD), the theory of strong interactions, at high temperatures. One of the exciting possibilities is the existence of thermodynamically distinct states of QCD, particularly a phase of de-confined quarks and gluons. An important step in establishing this new state of QCD is to demonstrate that the system has attained thermal equilibrium. We present a test of thermal equilibrium by checking that the mean hadron yields produced in the small impact parameter collisions as well as grand canonical fluctuations of conserved quantities give consistent temperature and baryon chemical potential for the last scattering surface. This consistency for moments up to third order of the net-baryon number, charge, and strangeness is a key step in the proof that the QCD matter produced in heavy-ion collision attains thermal equilibrium. It is a clear indication for the first time, using fluctuation observables, that a femto-scale system attains thermalization. The study also indicates that the relaxation time scales for the system are comparable to or smaller than the life time of the fireball.

hep-ph↗

arXiv2020

Energy-loss of heavy quarks in the isotropic collisional hot QCD medium at a finite chemical potential

The present article is the followup of {\color{blue} Eur.\ Phys.\ J.\ C {\bf 79}, 761 (2019)}, where we have studied the energy-loss of the heavy quarks traversing through the isotropic collisional hot QCD medium. Since, the exploration of QCD phase diagram is possible with the upcoming experimental facilities such as Anti-proton and Ion Research (FAIR) and Nuclotron-based Ion Collider fAcility (NICA), at finite baryon density and moderate temperature, the inclusion of finite chemical potential is essential to study the hot QCD/QGP medium. Therefore, the aim is to develop a formalism to study the energy-loss of heavy quarks moving in the interacting collisional hot QCD medium having small but a finite quark chemical potential. To do so, the extended effective fugacity quasi-particle model has been employed \cite{chandra_quasi1, chandra_quasi2, Mitra:2017sjo} while considering the effective kinetic theory approach using the Bhatnagar-Gross-Krook (BGK) collisional kernel. Finally, the momentum dependence of the energy-loss for the charm and bottom quark has been investigated at different values of collisions frequency and chemical potential. It is observed that as compared to charm quark, bottom quark loses less energy at a particular momentum, collisional frequency and chemical potential. Also, the energy-loss is seen to decrease with increasing chemical potential.

nucl-th↗