0000000001236121
AUTHOR
Subhasis Chattopadhyay
showing 32 related works from this author
Experimental Evidence for an Attractive p-φ Interaction
2021
Physical review letters 127(17), 172301 (2021). doi:10.1103/PhysRevLett.127.172301
Measurement of PromptD-Meson Production inp−PbCollisions atsNN=5.02 TeV
2014
The p_{T}-differential production cross sections of the prompt charmed mesons D^{0}, D^{+}, D^{*+}, and D_{s}^{+} and their charge conjugate in the rapidity interval -0.96<y_{cms}<0.04 were measured in p-Pb collisions at a center-of-mass energy sqrt[s_{NN}]=5.02 TeV with the ALICE detector at the LHC. The nuclear modification factor R_{pPb}, quantifying the D-meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%-20% uncertainties with unity in the transverse momentum interval 1<p_{T}<24 GeV/c. No significant difference among the R_{pPb} of the four D-meson species is observed. The results…
Suppression of Λ(1520) resonance production in central Pb-Pb collisions at sNN=2.76 TeV
2019
The production yield of the Λ(1520) baryon resonance is measured at midrapidity in Pb-Pb collisions at sNN = 2.76 TeV with the ALICE detector at the Large Hadron Collider (LHC). The measurement is performed in the Λ(1520)→pK− (and charge conjugate) hadronic decay channel as a function of the transverse momentum (pT) and collision centrality. The ratio of the pT-integrated production of Λ(1520) baryons relative to Λ baryons in central collisions is suppressed by about a factor of 2 with respect to peripheral collisions. This is the first observation of the suppression of a baryonic resonance at the LHC and the first 3σ evidence of Λ(1520) suppression within a single collision system. The mea…
J/ψ suppression at forward rapidity in Pb–Pb collisions at sNN=5.02 TeV
2017
The inclusive J/$\psi$ production has been studied in Pn-Pb and pp collisions at the centre-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}}=5.02$ TeV, using the ALICE detector at the CERN LHC. The J/$\psi$ meson is reconstructed, in the centre-of-mass rapidity interval $2.5<y<4$ and in the transverse-momentum range $p_{\rm T}<12$ GeV/$c$, via its decay to a muon pair. In this Letter, we present results on the inclusive J/$\psi$ cross section in pp collisions at $\sqrt{s}=5.02$ TeV and on the nuclear modification factor $R_{\rm AA}$. The latter is presented as a function of the centrality of the collision and, for central collisions, as a function of the transverse momentum $p_{\rm T}$ of…
Production of Muons from Heavy Flavor Decays at Forward Rapidity inppand Pb-Pb Collisions atsNN=2.76 TeV
2012
The ALICE Collaboration has measured the inclusive production of muons from heavy-flavor decays at forward rapidity, 2.5 < y < 4, in pp and Pb-Pb collisions at root s(NN) = 2.76 TeV. The p(t)-differential inclusive cross section of muons from heavy-flavor decays in pp collisions is compared to perturbative QCD calculations. The nuclear modification factor is studied as a function of p(t) and collision centrality. A weak suppression is measured in peripheral collisions. In the most central collisions, a suppression of a factor of about 3-4 is observed in 6 < p(t) < 10 GeV/c. The suppression shows no significant p(t) dependence.
Kaon-proton strong interaction at low relative momentum via femtoscopy in Pb-Pb collisions at the LHC
2021
Physics letters / B 822, 136708 (2021). doi:10.1016/j.physletb.2021.136708
Jet-hadron correlations measured relative to the second order event plane in Pb-Pb collisions at sNN=2.76TeV
2020
The quark gluon plasma produced in ultrarelativistic heavy-ion collisions at the Large Hadron Collider (LHC) can be studied by measuring the modifications of jets formed by hard scattered partons which interact with the medium. We studied these modifications via angular correlations of jets with charged hadrons for jets with momenta 20
Azimuthal anisotropy ofD-meson production in Pb-Pb collisions atsNN=2.76TeV
2014
The production of the prompt charmed mesons D0, D+, and D*+ relative to the reaction plane was measured in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision of √sNN=2.76TeV with the ALICE detector at the CERN Large Hadron Collider. D mesons were reconstructed via their hadronic decays at central rapidity in the transverse-momentum (p_T) interval 2–16 GeV/c. The azimuthal anisotropy is quantified in terms of the second coefficient v2 in a Fourier expansion of the D-meson azimuthal distribution and in terms of the nuclear modification factor R_AA, measured in the direction of the reaction plane and orthogonal to it. The v2 coefficient was measured with three different …
Study of very forward energy and its correlation with particle production at midrapidity in pp and p-Pb collisions at the LHC
2022
Journal of high energy physics 08(8), 86 (2022). doi:10.1007/JHEP08(2022)086
Measurement of transverse energy at midrapidity in Pb-Pb collisions atsNN=2.76TeV
2016
We report the transverse energy ($E_{\mathrm T}$) measured with ALICE at midrapidity in Pb-Pb collisions at ${\sqrt{s_{\mathrm {NN}}}}$ = 2.76 TeV as a function of centrality. The transverse energy was measured using identified single particle tracks. The measurement was cross checked using the electromagnetic calorimeters and the transverse momentum distributions of identified particles previously reported by ALICE. The results are compared to theoretical models as well as to results from other experiments. The mean $E_{\mathrm T}$ per unit pseudorapidity ($\eta$), $\langle $d$E_{\mathrm T}/$d$\eta \rangle$, in 0-5% central collisions is 1737 $\pm$ 6(stat.) $\pm$ 97(sys.) GeV. We find a si…
Measurement of electrons from semileptonic heavy-flavor hadron decays inppcollisions ats=2.76 TeV
2015
The pT-differential production cross section of electrons from semileptonic decays of heavy-flavor hadrons has been measured at midrapidity in proton-proton collisions at s=2.76TeV in the transverse momentum range 0.5<pT<12GeV/c with the ALICE detector at the LHC. The analysis was performed using minimum bias events and events triggered by the electromagnetic calorimeter. Predictions from perturbative QCD calculations agree with the data within the theoretical and experimental uncertainties.
Jet-associated deuteron production in pp collisions at s=13 TeV
2021
Author(s): Acharya, S; Adamova, D; Adler, A; Adolfsson, J; Aglieri Rinella, G; Agnello, M; Agrawal, N; Ahammed, Z; Ahmad, S; Ahn, SU; Akbar, Z; Akindinov, A; Al-Turany, M; Albuquerque, DSD; Aleksandrov, D; Alessandro, B; Alfanda, HM; Alfaro Molina, R; Ali, B; Ali, Y; Alici, A; Alizadehvandchali, N; Alkin, A; Alme, J; Alt, T; Altenkamper, L; Altsybeev, I; Anaam, MN; Andrei, C; Andreou, D; Andronic, A; Angeletti, M; Anguelov, V; Anticic, T; Antinori, F; Antonioli, P; Apadula, N; Aphecetche, L; Appelshauser, H; Arcelli, S; Arnaldi, R; Arratia, M; Arsene, IC; Arslandok, M; Augustinus, A; Averbeck, R; Aziz, S; Azmi, MD; Badala, A; Baek, YW; Bai, X; Bailhache, R; Bala, R; Balbino, A; Baldisseri, …
Alignment of the ALICE Inner Tracking System with cosmic-ray tracks
2010
ALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurement…
Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
2014
Measurements of multi-particle azimuthal correlations (cumulants) for charged particles in p-Pb and Pb-Pb collisions are presented. They help address the question of whether there is evidence for global, flow-like, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a $|\Delta \eta|$ gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high-multiplicity, indicating the prese…
Neutral pion and η meson production at midrapidity in Pb-Pb collisions at sNN=2.76 TeV
2018
Neutral pion and η meson production in the transverse momentum range 1 <pT< 20 GeV/c have been measured at midrapidity by the ALICE experiment at the Large Hadron Collider (LHC) in central and semicentral Pb-Pb collisions at sNN = 2.76 TeV. These results were obtained using the photon conversion method as well as the Photon Spectrometer (PHOS) and Electromagnetic Calorimeter detectors. The results extend the upper pT reach of the previous ALICE π0 measurements from 12 to 20 GeV/c and present the first measurement of η meson production in heavy-ion collisions at the LHC. The η/π0 ratio is similar for the two centralities and reaches at high pT a plateau value of 0.457 ± 0.013stat ± 0.018sys…
Constraints on jet quenching in p–Pb collisions at sNN=5.02 TeV measured by the event-activity dependence of semi-inclusive hadron-jet distributions
2018
The ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high-transverse momentum trigger hadron in p–Pb collisions at √sNN = 5.02 TeV. Jets are reconstructed from charged-particle tracks using the anti-kT algorithm with resolution parameter R = 0.2 and 0.4. A data-driven statistical approach is used to correct the uncorrelated background jet yield. Recoil jet distributions are reported for jet transverse momentum 15 < pch T,jet < 50 GeV/c and are compared in various intervals of p–Pb event activity, based on charged-particle multiplicity and zero-degree neutral energy in the forward (Pb-going) direction. The semi-inclusive ob…
Unveiling the strong interaction among hadrons at the LHC
2020
One of the key challenges for nuclear physics today is to understand from first principles the effective interaction between hadrons with different quark content. First successes have been achieved using techniques that solve the dynamics of quarks and gluons on discrete space-time lattices1,2. Experimentally, the dynamics of the strong interaction have been studied by scattering hadrons off each other. Such scattering experiments are difficult or impossible for unstable hadrons3–6 and so high-quality measurements exist only for hadrons containing up and down quarks7. Here we demonstrate that measuring correlations in the momentum space between hadron pairs8–12 produced in ultrarelativistic…
Search for collectivity with azimuthal J/ψ-hadron correlations in high multiplicity p–Pb collisions at sNN=5.02 and 8.16 TeV
2018
A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences and Nationalstiftung fur Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Universidade Federal do Rio Grande do Sul (UFRGS), Financiadora de Estudos e Projetos (Finep) and Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Brazil; Ministry of Science & Technology of China (MSTC), National Natural Science Foundation of Chi…
One-dimensional charged kaon femtoscopy in p -Pb collisions at sNN = 5.02 TeV
2019
The correlations of identical charged kaons were measured in p-Pb collisions at √sNN=5.02 TeV by the ALICE experiment at the LHC. The femtoscopic invariant radii and correlation strengths were extracted from one-dimensional kaon correlation functions and were compared with those obtained in pp and Pb-Pb collisions at √s=7 TeV and √sNN=2.76 TeV, respectively. The presented results also complement the identical-pion femtoscopic data published by the ALICE collaboration. The extracted radii increase with increasing charged-particle multiplicity and decrease with increasing pair transverse momentum. At comparable multiplicities, the radii measured in p-Pb collisions are found to be close to tho…
Midrapidity Antiproton-to-Proton Ratio inppCollisons ats=0.9and 7 TeV Measured by the ALICE Experiment
2010
The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at root s = 0.9 and 7 TeV during the initial running periods of the Large Hadron Collider. The measurement covers the transverse momentum interval 0.45 < p(t) < 1.05 GeV/c and rapidity vertical bar y vertical bar < 0.5. The ratio is measured to be R-vertical bar y vertical bar<0.5 = 0.957 +/- 0.006(stat) +/- 0.0014(syst) at 0.9 Tev and R-vertical bar y vertical bar<0.5 = 0.991 +/- 0.005 +/- 0.014(syst) at 7 TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on a…
Jet-like correlations with neutral pion triggers in pp and central Pb–Pb collisions at 2.76 TeV
2016
Physics letters / B B763, 238 - 250 (2016). doi:10.1016/j.physletb.2016.10.048
Λc+ Production and Baryon-to-Meson Ratios in pp and p -Pb Collisions at sNN=5.02 TeV at the LHC
2021
The prompt production of the charm baryon Λ c + and the Λ c + / D 0 production ratios were measured at midrapidity with the ALICE detector in p p and p -Pb collisions at s NN = 5.02 TeV . These new measurements show a clear decrease of the Λ c + / D 0 ratio with increasing transverse momentum ( p T ) in both collision systems in the range 2 p T 12 GeV / c , exhibiting similarities with the light-flavor baryon-to-meson ratios p / π and Λ / K S 0 . At low p T , predictions that include additional color-reconnection mechanisms beyond the leading-color approximation, assume the existence of additional higher-mass charm-baryon states, or include hadronization via coalescence can describe the dat…
Precision measurement of the mass difference between light nuclei and anti-nuclei
2015
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons and anti-deuterons, and $^{3}{\rm He}$ and $^3\overline{\rm He}…
Multiplicity dependence of jet-like two-particle correlation structures in p–Pb collisions at sNN=5.02 TeV
2015
Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7<pT,assoc<pT,trig<5.0 GeV/c is examined, to include correlations induced by jets originating from low momentum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range |η|<0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the no…
First study of the two-body scattering involving charm hadrons
2022
Physical review / D 106(5), 052010 (2022). doi:10.1103/PhysRevD.106.052010
Performance of the ALICE VZERO system
2013
ALICE is an LHC experiment devoted to the study of strongly interacting matter in proton-proton, proton--nucleus and nucleus-nucleus collisions at ultra-relativistic energies. The ALICE VZERO system, made of two scintillator arrays at asymmetric positions, one on each side of the interaction point, plays a central role in ALICE. In addition to its core function as a trigger, the VZERO system is used to monitor LHC beam conditions, to reject beam-induced backgrounds and to measure basic physics quantities such as luminosity, particle multiplicity, centrality and event plane direction in nucleus-nucleus collisions. After describing the VZERO system, this publication presents its performance o…
Two-particle differential transverse momentum and number density correlations in p−Pb collisions at 5.02 TeV and Pb-Pb collisions at 2.76 TeV at the …
2019
The production cross section and the transverse momentum distribution of charged particles is measured in pp collisions at √s = 2.76 TeV, 5.02 TeV, 7 TeV and 13 TeV, as well as for Pb-Pb collision at √s_NN = 5.02 TeV and Xe-Xe at √s_NN = 5.44 TeV in ALICE at the LHC. The measurement is performed in the transverse momentum region of 0.15 results show a faster-than-linear increase with the center-of-mass energy and follow a similar trend with respect to previous measurements. The analysis of the p_T spectra in multiplicity intervals show a weak center-of-mass energy dependence when they are compared to their respective inelastic (INEL) pp measurement. The average multiplicity as a function of…
Inclusive heavy-flavour production at central and forward rapidity in Xe–Xe collisions at TeV
2021
The first measurements of the production of muons and electrons from heavy-flavour hadron decays in Xe–Xe collisions at sNN=5.44 TeV, using the ALICE detector at the LHC, are reported. The measurement of the nuclear modification factor RAA is performed as a function of transverse momentum pT in several centrality classes at forward rapidity (2.5<y<4) and midrapidity (|y|<0.8) for muons and electrons from heavy-flavour hadron decays, respectively. A suppression by a factor up to about 2.5 compared to the binary-scaled pp reference is observed in central collisions at both central and forward rapidities. The RAA of muons from heavy-flavour hadron decays is compared to previous measur…
Investigations of Anisotropic Flow Using Multiparticle Azimuthal Correlations in pp, p-Pb, Xe-Xe, and Pb-Pb Collisions at the LHC
2019
Measurements of anisotropic flow coefficients ($v_n$) and their cross-correlations using two- and multi-particle cumulant methods are reported in collisions of pp at $\sqrt{s} = 13$ TeV, p-Pb at $\sqrt{s_{_{\rm NN}}} = 5.02$ TeV, Xe-Xe at $\sqrt{s_{_{\rm NN}}} = 5.44$ TeV, and Pb-Pb at $\sqrt{s_{_{\rm NN}}} = 5.02$ TeV recorded with the ALICE detector. The multiplicity dependence of $v_n$ is studied in a very wide range from 20 to 3000 particles produced in the mid-rapidity region $|��|<0.8$ for the transverse momentum range $0.2 < p_{\rm T} < 3.0$ GeV/$c$. An ordering of the coefficients $v_2 > v_3 > v_4$ is found in pp and p-Pb collisions, similar to that seen in large coll…
Global polarization of Λ and Λ¯ hyperons in Pb-Pb collisions at sNN= 2.76 and 5.02 TeV
2020
The global polarization of the $\Lambda$ and $\overline\Lambda$ hyperons is measured for Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 and 5.02 TeV recorded with the ALICE at the LHC. The results are reported differentially as a function of collision centrality and hyperon's transverse momentum ($p_{\rm{T}}$) for the range of centrality 5-50%, $0.5 < p_{\rm{T}} <5$ GeV/$c$, and rapidity $|y|<0.5$. The hyperon global polarization averaged for Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 and 5.02 TeV is found to be consistent with zero, $\langle P_{\rm{H}}\rangle$ (%) $\approx$ 0.01 $\pm$ 0.06 (stat.) $\pm$ 0.03 (syst.) in the collision centrality range 15-50%, where the largest signal i…
Calibration of the photon spectrometer PHOS of the ALICE experiment
2019
Journal of Instrumentation 14(05), P05025 - P05025 (2019). doi:10.1088/1748-0221/14/05/P05025
Characterizing the initial conditions of heavy-ion collisions at the LHC with mean transverse momentum and anisotropic flow correlations
2022
Physics letters / B 834, 137393 (2022). doi:10.1016/j.physletb.2022.137393