S. K. Gupta
A5041964953- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Advanced Thermoelectric Materials and Devices
- Nuclear physics research studies
- Nuclear reactor physics and engineering
- Nuclear Physics and Applications
- Particle Detector Development and Performance
- Chalcogenide Semiconductor Thin Films
- Solar and Space Plasma Dynamics
- Magnetic and transport properties of perovskites and related materials
- Radiation Therapy and Dosimetry
- Atomic and Subatomic Physics Research
- X-ray Spectroscopy and Fluorescence Analysis
- Luminescence Properties of Advanced Materials
- 2D Materials and Applications
- Physics of Superconductivity and Magnetism
- Radiation Detection and Scintillator Technologies
- Ion-surface interactions and analysis
- Advanced Condensed Matter Physics
- Thermal properties of materials
- Agricultural pest management studies
- Superconducting Materials and Applications
Homi Bhabha National Institute
2025
Bhabha Atomic Research Centre
2009-2025
Tribhuvan University Teaching Hospital
2025
Central Soil Salinity Research Institute
2024
Chandigarh University
2023-2024
Dibrugarh University
2023
Indian Institute of Technology Kanpur
2019-2023
Tata Institute of Fundamental Research
2019-2023
Aligarh Muslim University
2019-2023
International Crops Research Institute for the Semi-Arid Tropics
2023
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,...
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...
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...
We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions square root of [s(NN)] = 130 GeV measured with PHENIX detector RHIC. For 5% most central we find dN(ch)/d eta(vertical line eta 0) 622+/-1(stat)+/-41(syst). The results, analyzed as a function centrality, show steady rise particle density per participating nucleon centrality.
Silicon germanium alloys (Si80Ge20) have been used in thermoelectric generators for deep space missions to convert radioisotope heat into electricity. This work demonstrates the highest value of figure-of-merit (ZT) ∼1.84 at 1073 K n-type SiGe nanostructured bulk alloys, which is 34% higher than reported record alloys. The optimized samples exhibit a Seebeck coefficient ∼284 μV K−1, resistivity ∼45 μΩ m and thermal conductivity ∼0.93 W m−1 K−1 K. main contributing factor enhanced ZT very low...
A systematic study is presented for centrality, transverse momentum (${p}_{T}$), and pseudorapidity ($\ensuremath{\eta}$) dependence of the inclusive charged hadron elliptic flow (${v}_{2}$) at midrapidity ($|\ensuremath{\eta}|<1.0$) in $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{NN}}=7.7$, 11.5, 19.6, 27, 39 GeV. The results obtained with different methods, including correlations event plane reconstructed a region separated by large gap four-particle cumulants (${v}_{2}{4}$), are to...
We report measurements of charmed-hadron $({D}^{0},{D}^{*})$ production cross sections at midrapidity in $p+p$ collisions a center-of-mass energy 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via hadronic decays ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$, ${D}^{*+}\ensuremath{\rightarrow}{D}^{0}{\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{+}$ and their charge conjugates,...
We report the first measurement of elliptic anisotropy (v_{2}) charm meson D^{0} at midrapidity (|y|<1) in Au+Au collisions sqrt[s_{NN}]=200 GeV. The was conducted by STAR experiment RHIC utilizing a new high-resolution silicon tracker. measured v_{2} 0%-80% centrality can be described viscous hydrodynamic calculation for transverse momentum (p_{T}) less than 4 GeV/c. as function kinetic energy (m_{T}-m_{0}, where m_{T}=sqrt[p_{T}^{2}+m_{0}^{2}]) is consistent with that light mesons 10%-40%...
We report new STAR measurements of mid-rapidity yields for the $\Lambda$, $\bar{\Lambda}$, $K^{0}_{S}$, $\Xi^{-}$, $\bar{\Xi}^{+}$, $\Omega^{-}$, $\bar{\Omega}^{+}$ particles in Cu+Cu collisions at \sNN{200}, and $K^{0}_{S}$ Au+Au \sNN{200}. show that a given number participating nucleons, production strange hadrons is higher than same center-of-mass energy. find aspects enhancement factors all can be described by parameterization based on fraction participants undergo multiple collisions.
Fluctuations of conserved quantities such as baryon number, charge, and strangeness are sensitive to the correlation length hot dense matter created in relativistic heavy-ion collisions can be used search for QCD critical point. We report first measurements moments net-kaon multiplicity distributions Au+Au at sNN=7.7, 11.5, 14.5, 19.6, 27, 39, 62.4, 200 GeV. The collision centrality energy dependence mean (M), variance (σ2), skewness (S), kurtosis (κ) well ratio σ2/M products Sσ κσ2...
We present measurements of π− and π+ elliptic flow, v2, at midrapidity in Au+Au collisions √sNN=200, 62.4, 39, 27, 19.6, 11.5, 7.7 GeV, as a function event-by-event charge asymmetry, Ach, based on data from the STAR experiment RHIC. find that (π+) flow linearly increases (decreases) with asymmetry for most centrality bins √sNN=27 GeV higher. At √sNN=200 slope difference v2 between Ach exhibits dependence, which is qualitatively similar to calculations incorporate chiral magnetic wave effect....
Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- four-particle cumulants, $v_2\{2\}$ $v_2\{4\}$, for charged hadrons from U+U collisions at $\sqrt{s_{\rm NN}}$ = 193 GeV Au+Au 200 GeV. Nearly fully overlapping selected based amount of energy deposited by spectators STAR Zero Degree Calorimeters (ZDCs). Within this sample, observed dependence multiplicity...
We present ΛΛ correlation measurements in heavy-ion collisions for Au+Au at sqrt[s_{NN}]=200 GeV using the STAR experiment Relativistic Heavy-Ion Collider. The Lednický-Lyuboshitz analytical model has been used to fit data obtain a source size, scattering length and an effective range. Implications of measurement function interaction parameters dihyperon searches are discussed.
We report measurements of ϒ meson production in p+p, d+Au, and Au+Au collisions using the STAR detector at RHIC. compare yield to measured cross section p+p order quantify any modifications cold nuclear matter d+Au data hot separated into three centrality classes. Our measurement is based on times statistics our previous result. obtain a modification factor for ϒ(1S+2S+3S) rapidity range |y|<1 RdAu=0.79±0.24(stat.)±0.03(syst.)±0.10(p+psyst.). A comparison with models including shadowing...
We present results of analyses two-pion interferometry in $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{\mathit{NN}}}=7.7$, 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured the STAR detector as part BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown--Twiss radii) are studied a function beam energy, azimuthal angle relative to reaction plane, centrality, transverse mass (${m}_{T}$) particles. analysis allows extraction...
The STAR Collaboration reports the measurement of semi-inclusive distributions charged-particle jets recoiling from a high transverse momentum hadron trigger, in central and peripheral $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{{s}_{\mathrm{NN}}}=200$ GeV. Charged are reconstructed with anti-${k}_{\mathrm{T}}$ algorithm for jet radii $R$ between 0.2 0.5 low infrared cutoff track constituents (${p}_{\mathrm{T}}>0.2 \mathrm{GeV}/\mathrm{c}$). A novel mixed-event technique is used to...
We present the measurement of transverse single-spin asymmetry weak boson production in transversely polarized proton-proton collisions at $\sqrt{s} = 500~\text{GeV}$ by STAR experiment RHIC. The measured observable is sensitive to Sivers function, one momentum dependent parton distribution functions, which predicted have opposite sign from that observed deep inelastic lepton-proton scattering. These data provide first experimental investigation non-universality fundamental our understanding QCD.
A measurement of direct photon production in ${}^{208}\mathrm{Pb}{+}^{208}\mathrm{Pb}$ collisions at $158A$ GeV has been carried out the CERN WA98 experiment. The invariant yield photons central is extracted as a function transverse momentum interval $0.5<{p}_{T}<4\mathrm{GeV}/c$. significant signal, compared to statistical and systematical errors, seen ${p}_{T}>1.5\mathrm{GeV}/c$. result constitutes first observation ultrarelativistic heavy-ion collisions. It could be for diagnosis...
Transverse momentum spectra and yields of hadrons are measured by the PHENIX collaboration in $\text{Au}+\text{Au}$ collisions at $\sqrt{{s}_{NN}}=130\phantom{\rule{0.3em}{0ex}}\text{GeV}$ Relativistic Heavy Ion Collider. The time-of-flight resolution allows identification pions to transverse momenta $2\phantom{\rule{0.3em}{0ex}}\text{GeV}∕c$ protons antiprotons $4\phantom{\rule{0.3em}{0ex}}\text{GeV}∕c$. yield rises approximately linearly with number nucleons participating collision, while...
The first measurement of energy produced transverse to the beam direction at Relativistic Heavy-Ion Collider Brookhaven National Laboratory is presented. midrapidity density per participating nucleon rises steadily with number participants, closely paralleling rise in charged-particle density, such that <E(T)>/<N(ch)> remains relatively constant as a function centrality. calculated via Bjorken's prescription for 2% most central Au+Au collisions square root[s(NN)] = 130 GeV least epsilon(Bj)...
The efficient conversion of heat into electricity using a thermoelectric approach requires high performance materials with the figure merit ZT ≥ 1. Here we report on bulk CuCrSe2, which exhibits very ∼ 1 at 773 K. titled compound an electrical resistivity ∼2.8 mΩ cm, Seebeck coefficient ∼160 μV K−1, together low thermal conductivity ∼7 mW cm−1 K−1 CuCrSe2 is attributed to phonon scattering by various sources such as (i) superionic Cu ions between CrSe2 layers, (ii) nanoscale precipitates in...
We report transverse momentum (${p}_{T}\ensuremath{\le}15\text{ }\text{ }\mathrm{GeV}/c$) spectra of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, ${K}^{\ifmmode\pm\else\textpm\fi{}}$, $p$, $\overline{p}$, ${K}_{S}^{0}$, and ${\ensuremath{\rho}}^{0}$ at midrapidity in $p+p$ $\mathrm{Au}+\mathrm{Au}$ collisions $\sqrt{{s}_{NN}}=200\text{ }\mathrm{GeV}$. Perturbative QCD calculations are consistent with ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ but do not reproduce $K$...