S. Chattopadhyay
A5060036474- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Neutrino Physics Research
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Nuclear reactor physics and engineering
- Radiation Detection and Scintillator Technologies
- Nuclear physics research studies
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Atomic and Molecular Physics
- Superconducting Materials and Applications
- Indian History and Philosophy
- CCD and CMOS Imaging Sensors
- Nuclear Physics and Applications
- Stochastic processes and statistical mechanics
- Plasma Diagnostics and Applications
- Theology and Philosophy of Evil
- Theoretical and Computational Physics
- Indian and Buddhist Studies
- Atomic and Subatomic Physics Research
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Effects in Electronics
Homi Bhabha National Institute
2016-2025
Saha Institute of Nuclear Physics
2016-2025
Variable Energy Cyclotron Centre
2016-2025
College of Medicine & JNM Hospital
2025
SRM Institute of Science and Technology
2025
A. Alikhanyan National Laboratory
2015-2024
University of Wisconsin–Madison
2023-2024
National Institute of Science Education and Research
2021-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Torino
2014-2024
Lawrence Berkeley National Laboratory
1995-2024
Identified charged-particle spectra of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ifmmode\pm\else\textpm\fi{}}$, $p$, and $\overline{p}$ at midrapidity ($|y|<0.1$) measured by the $\mathit{dE}/\mathit{dx}$ method in STAR (solenoidal tracker BNL Relativistic Heavy Ion Collider) time projection chamber are reported for $\mathit{pp}$ $d+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathit{NN}}}=200$ GeV $\mathrm{Au}+\mathrm{Au}$ 62.4, 130, 200 GeV. Average transverse momenta, total...
We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions charged hadrons at high transverse momentum (high p(T)) in minimum bias central d+Au collisions sqrt[s(NN)]=200 GeV. The yield is enhanced relative to binary-scaled p+p collisions, while the are very similar those observed collisions. These results demonstrate that strong suppression back-to-back correlations p(T) previously Au+Au due final-state interactions with dense medium generated such
The results from the STAR Collaboration on directed flow (${v}_{1}$), elliptic (${v}_{2}$), and fourth harmonic (${v}_{4}$) in anisotropic azimuthal distribution of particles Au+Au collisions at $\sqrt{{s}_{\mathit{NN}}}=200\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}$ are summarized compared with other experiments theoretical models. Results for identified presented fit a blast-wave model. Different analysis methods nonflow effects extracted data. For ${v}_{2}$, scaling number constituent quarks...
We present STAR measurements of the azimuthal anisotropy parameter v(2) and binary-collision scaled centrality ratio R(CP) for kaons lambdas (Lambda+Lambda) at midrapidity in Au+Au collisions square root s(NN)=200 GeV. In combination, particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation vacuum. establish p(T) approximately 5 GeV/c as value where dependent baryon enhancement ends. The K(0)(S) Lambda+Lambda values are consistent with...
Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted lead charge separation quarks along system's orbital momentum axis. We investigate a three-particle azimuthal correlator which is $\mathcal{P}$ even observable, but directly sensitive effect. report measurements charged hadrons near center-of-mass rapidity with this observable in $\mathrm{Au}+\mathrm{Au}$ and...
We present measurements of bulk properties the matter produced in Au+Au collisions at $\sqrt{s_{NN}}=$ 7.7, 11.5, 19.6, 27, and 39 GeV using identified hadrons ($\pi^\pm$, $K^\pm$, $p$ $\bar{p}$) from STAR experiment Beam Energy Scan (BES) Program Relativistic Heavy Ion Collider (RHIC). Midrapidity ($|y|<$0.1) results for multiplicity densities $dN/dy$, average transverse momenta $\langle p_T \rangle$ particle ratios are presented. The chemical kinetic freeze-out dynamics these energies...
Charged hadrons in [EQUATION: SEE TEXT] associated with particles of are reconstructed pp and Au+Au collisions at sqrt[sNN]=200 GeV. The multiplicity p magnitude sum found to increase from central collisions. distributions, while similar shape on the nearside, significantly softened awayside relative not much harder than that inclusive hadrons. results, consistent jet quenching, suggest fragments approach equilibration medium traversed.
We report the beam energy (sqrt[sNN]=7.7-200 GeV) and collision centrality dependence of mean (M), standard deviation (σ), skewness (S), kurtosis (κ) net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by STAR experiment at midrapidity (|y|<0.5) within transverse momentum range 0.4<pT<0.8 GeV/c first phase Beam Energy Scan program Relativistic Heavy Ion Collider. These important for understanding quantum chromodynamic diagram. products moments, Sσ κσ2,...
The STAR collaboration at the BNL Relativistic Heavy-Ion Collider (RHIC) reports measurements of inclusive yield nonphotonic electrons, which arise dominantly from semileptonic decays heavy flavor mesons, over a broad range transverse momenta ($1.2<{p}_{T}<10\text{ }\text{ }\mathrm{GeV}/c$) in $p+p$, $d+\mathrm{Au}$, and $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathrm{NN}}}=200\text{ }\mathrm{GeV}$. electron exhibits an unexpectedly large suppression central high ${p}_{T}$,...
We present strange particle spectra and yields measured at midrapidity in $\sqrt{s}=200$ GeV proton-proton ($p+p$) collisions the BNL Relativistic Heavy Ion Collider (RHIC). find that previously observed universal transverse mass (${m}_{T}\ensuremath{\equiv}\sqrt{{{p}_{T}}^{2}+{m}^{2}}$) scaling of hadron production $p+p$ seems to break down higher ${m}_{T}$ there is a difference shape spectrum between baryons mesons. observe antibaryon baryon ratios near unity for \ensuremath{\Lambda}...
Parity ($\mathcal{P}$)-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted lead charge separation quarks along orbital momentum system in noncentral To study this effect, we investigate a three-particle mixed-harmonics azimuthal correlator which is $\mathcal{P}$-even observable, but directly sensitive charge-separation effect. We report measurements observable using STAR...
We report the first measurements of kurtosis (\kappa), skewness (S) and variance (\sigma^2) net-proton multiplicity (N_p - N_pbar) distributions at midrapidity for Au+Au collisions \sqrt(s_NN) = 19.6, 62.4, 200 GeV corresponding to baryon chemical potentials (\mu_B) between 20 MeV. Our products \kappa \sigma^2 S \sigma, which can be related theoretical calculations sensitive number susceptibilities long range correlations, are constant as functions collision centrality. compare these with...
We report the first measurements of moments -- mean ($M$), variance ($\sigma^{2}$), skewness ($S$) and kurtosis ($\kappa$) net-charge multiplicity distributions at mid-rapidity in Au+Au collisions seven energies, ranging from $\sqrt {{s_{\rm NN}}}$= 7.7 to 200 GeV, as a part Beam Energy Scan program RHIC. The are related thermodynamic susceptibilities net-charge, sensitive proximity QCD critical point. compare products moments, $\sigma^{2}/M$, $S\sigma$ $\kappa\sigma^{2}$ with expectations...
Global polarization of $\Lambda$ hyperons has been measured to be the order a few tenths percent in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV, with no significant difference between and $\bar{\Lambda}$. These new results reveal collision energy dependence global together previously observed 7.7 -- 62.4 GeV indicate noticeable vorticity medium created non-central heavy-ion highest RHIC energy. The signal is rough quantitative agreement theoretical predictions from hydrodynamic model...
The STAR Collaboration at the Relativistic Heavy Ion Collider presents a systematic study of high-transverse-momentum charged-di-hadron correlations small azimuthal pair separation $\ensuremath{\Delta}\ensuremath{\phi}$ in $d+\mathrm{Au}$ and central $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{\mathit{NN}}}=200$ GeV. Significant correlated yield for pairs with large longitudinal $\ensuremath{\Delta}\ensuremath{\eta}$ is observed collisions, contrast to collisions. associated...
Nuclear collisions recreate conditions in the universe microseconds after Big Bang. Only a very small fraction of emitted fragments are light nuclei, but these states fundamental interest. We report observation antihypertritons - composed an antiproton, antineutron, and antilambda hyperon produced by colliding gold nuclei at high energy. Our analysis yields 70 +- 17 157 30 hypertritons. The measured hypertriton (antihypertriton) helium3 (antihelium3) similar, suggesting equilibrium...
Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y=0) are reported in sNN=7.7, 11.5, 19.6, 27, 39, 62.4, 200 GeV Au+Au collisions as recorded by the STAR detector at Relativistic Heavy Ion Collider. At intermediate impact parameters, proton net-proton slope parameter dv1/dy|y=0 shows a minimum between 11.5 19.6 GeV. In addition, changes sign twice 7.7 39 The results qualitatively resemble predictions of hydrodynamic model with...
We report the first measurement of charmed-hadron (D(0)) production via hadronic decay channel (D(0) → K(-) + π(+)) in Au+Au collisions at sqrt[s(NN)] = 200 GeV with STAR experiment. The charm cross section per nucleon-nucleon collision midrapidity scales number binary collisions, N(bin), from p+p to central collisions. D(0) meson yields Au are strongly suppressed compared those scaled by for transverse momenta p(T) > 3 GeV/c, demonstrating significant energy loss quarks hot and dense...
Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local manifest themselves as charge separation along the magnetic field axis via chiral effect. experimental observation of previously reported for collisions at top RHIC energies. In this Letter, we present results beam-energy dependence correlations $\mathrm{Au}+\mathrm{Au}$ midrapidity center-of-mass energies 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from...
The Λ (Λ[over ¯]) hyperon polarization along the beam direction has been measured in Au+Au collisions at sqrt[s_{NN}]=200 GeV, for first time heavy-ion collisions. dependence on hyperons' emission angle relative to elliptic flow plane exhibits a second harmonic sine modulation, indicating quadrupole pattern of vorticity component direction, expected due flow. is found increase more peripheral collisions, and shows no strong transverse momentum (p_{T}) p_{T} greater than 1 GeV/c. magnitude...
The chiral magnetic effect (CME) is predicted to occur as a consequence of local violation $\mathcal{P}$ and $\mathcal{C}P$ symmetries the strong interaction amidst electromagnetic field generated in relativistic heavy-ion collisions. Experimental manifestation CME involves separation positively negatively charged hadrons along direction field. Previous measurements CME-sensitive charge-separation observables remain inconclusive because large background contributions. To better control...
We report a systematic measurement of cumulants, $C_{n}$, for net-proton, proton and antiproton multiplicity distributions, correlation functions, $\kappa_n$, distributions up to the fourth order in Au+Au collisions at $\sqrt{s_{\mathrm {NN}}}$ = 7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4 200 GeV. The $C_{n}$ $\kappa_n$ are presented as function collision energy, centrality kinematic acceptance rapidity, $y$, transverse momentum, $p_{T}$. data were taken during first phase Beam Energy Scan...