Zubayer Ahammed

• Variable Energy Cyclotron Centre

The physics studies at heavy-ion nucleus-nucleus collision experiments demand reliable detectors at high particle flux. Therefore, Gas Electron Multipliers (GEM) detectors, which show resilience to extreme radiation, are one of the prime choices for the upcoming Compressed Baryonic Matter (CBM) experiment at the Facility of Antiproton and Ion Resea...

A bstract Short-range correlations between charged particles are studied via two-particle angular correlations in pp collisions at $$ \sqrt{s} $$ s = 13 TeV. The correlation functions are measured as a function of the relative azimuthal angle ∆ φ and the pseudorapidity separation ∆ η for pairs of primary charged particles within the pseudorapidity...

The Compress Baryonic Matter experiment (CBM) at the upcoming Facility for Anti-proton and Ion Research, a fixed-target experiment with high interaction rates, aims to study the equation of state of baryon-dominated, strongly interacting matter ( μ B ∼ 540–800 MeV). The Muon Chamber is a key sub-system designed to detect dimuons decaying from low m...

The femtoscopic study of pairs of identical pions is particularly suited to investigate the effective source function of particle emission, due to the resulting Bose–Einstein correlation signal. In small collision systems at the LHC, pp in particular, the majority of the pions are produced in resonance decays, which significantly affect the profile...

This is an addendum to the article “Dielectron production in proton-proton and proton-lead collisions at s NN = 5.02 TeV ” published in ]. We update the extracted charm cross section at midrapidity given in Table III and Fig. 4 (left) of the original publication with the fragmentation fractions of charm quarks in p p collisions published in ]. ©20...

The production cross section of inclusive isolated photons has been measured by the ALICE experiment at the CERN LHC in pp collisions at centre-of-momentum energy of $$\sqrt{s} =13$$ s = 13 TeV collected during the LHC Run 2 data-taking period. The measurement is performed by combining the measurements of the electromagnetic calorimeter EMCal and t...

The transverse momentum (\(p_{\textrm{T}}\)) differential production cross section of the promptly produced charm-strange baryon \(\mathrm {\Xi _{c}^{0}}\) (and its charge conjugate \(\overline{\mathrm {\Xi _{c}^{0}}}\)) is measured at midrapidity via its hadronic decay into \(\mathrm{\pi ^{+}}\Xi ^{-}\) in p–Pb collisions at a centre-of-mass energ...

This paper reports the first measurement of the transverse momentum ( p T ) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at s = 13 TeV . Flattenicity is a novel event shape observable that is measured in the pseudorapidity intervals covered by...

This Letter presents the first measurement of event-by-event fluctuations of the net number (difference between the particle and antiparticle multiplicities) of multistrange hadrons Ξ − and Ξ ¯ + and its correlation with the net-kaon number using the data collected by the ALICE Collaboration in pp, p-Pb, and Pb-Pb collisions at a center-of-mass ene...

First measurements of hadron- Λ ( h − Λ ) azimuthal angular correlations in p -Pb collisions at s N N = 5.02 TeV using the ALICE detector at the Large Hadron Collider are presented. These correlations are used to separate the production of associated Λ baryons into three different kinematic regions, namely those produced in the direction of the tri...

This work aims to differentiate strangeness produced from hard processes (jetlike) and softer processes (underlying event) by measuring the angular correlation between a high-momentum trigger hadron ( h ) acting as a jet proxy and a produced strange hadron [ ϕ ( 1020 ) meson]. Measuring h − ϕ correlations at midrapidity in p -Pb collisions at s N N...

The total charm-quark production cross section per unit of rapidity \(\textrm{d}\sigma ({{\textrm{c}}\overline{\textrm{c}}})/\textrm{d}y\), and the fragmentation fractions of charm quarks to different charm-hadron species \(f(\textrm{c}\rightarrow {\textrm{h}}_{\textrm{c}})\), are measured for the first time in p–Pb collisions at \(\sqrt{s_\textrm{...

A bstract The production cross sections of D ⁰ , D ⁺ , and $$ {\Lambda}_{\textrm{c}}^{+} $$ Λ c + hadrons originating from beauty-hadron decays (i.e. non-prompt) were measured for the first time at midrapidity in proton–lead (p–Pb) collisions at the center-of-mass energy per nucleon pair of $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 5 . 02 TeV. Nuclear mo...

Deuterons are atomic nuclei composed of a neutron and a proton held together by the strong interaction. Unbound ensembles composed of a deuteron and a third nucleon have been investigated in the past using scattering experiments, and they constitute a fundamental reference in nuclear physics to constrain nuclear interactions and the properties of n...

A bstract The angular correlations between charged Ξ baryons and associated identified hadrons (pions, kaons, protons, Λ baryons, and Ξ baryons) are measured in pp collisions at $$ \sqrt{s} $$ s = 13 TeV with the ALICE detector to give insight into the particle production mechanisms and balancing of quantum numbers on the microscopic level. In part...

A bstract The azimuthal anisotropy of particles associated with jets (jet particles) at midrapidity is measured for the first time in p-Pb and Pb-Pb collisions at $$ \sqrt{{\textrm{s}}_{\textrm{NN}}} $$ s NN = 5 . 02 TeV down to transverse momentum ( p T ) of 0.5 GeV/ c and 2 GeV/ c , respectively, with ALICE. The results obtained in p-Pb collision...

This Letter presents the most precise measurement to date of the matter-antimatter imbalance at midrapidity in Pb-Pb collisions at a center-of-mass energy per nucleon pair s NN = 5.02 TeV . Using the Statistical Hadronization framework, it is possible to obtain the value of the electric charge and baryon chemical potentials, μ Q = − 0.18 ± 0.90 MeV...

The inclusive production of the charm-strange baryon Ω c 0 is measured for the first time via its semileptonic decay into Ω − e + ν e at midrapidity ( | y | < 0.8 ) in proton-proton (pp) collisions at the center-of-mass energy s = 13 TeV with the ALICE detector at the LHC. The transverse momentum ( p T ) differential cross section multiplied by the...

The two-particle momentum correlation functions between charm mesons ( D * ± and D ± ) and charged light-flavor mesons ( π ± and K ± ) in all charge combinations are measured for the first time by the ALICE Collaboration in high-multiplicity proton–proton collisions at a center-of-mass energy of s = 13 TeV . For DK and D * K pairs, the experimental...

Measurements of exclusive J/ψ, ψ(2s), and electron-positron (e+e−) pair photoproduction in Au+Au ultraperipheral collisions are reported by the STAR experiment at sNN=200GeV. We report several first measurements at the BNL Relativistic Heavy Ion Collider, which are (i) J/ψ photoproduction with large momentum transfer up to 2.2(GeV/c)2, (ii) coheren...

We report a measurement of exclusive J/ψ and ψ(2s) photoproduction in Au+Au ultraperipheral collisions at sNN=200 GeV using the STAR detector. For the first time, (i) the ψ(2s) photoproduction in midrapidity at the Relativistic Heavy-Ion Collider has been experimentally measured; (ii) nuclear suppression factors are measured for both the coherent a...

Measurements of the p T -dependent flow vector fluctuations in Pb–Pb collisions at s NN = 5.02 TeV using azimuthal correlations with the ALICE experiment at the Large Hadron Collider are presented. A four-particle correlation approach [ALICE Collaboration, ] is used to quantify the effects of flow angle and magnitude fluctuations separately. This p...

K + K − pairs may be produced in photonuclear collisions, either from the decays of photoproduced ϕ ( 1020 ) mesons or directly as nonresonant K + K − pairs. Measurements of K + K − photoproduction probe the couplings between the ϕ ( 1020 ) and charged kaons with photons and nuclear targets. The kaon-proton scattering occurs at energies far above t...

A bstract The production yields of the Σ(1385) ± and Ξ(1530) ⁰ resonances are measured in pp collisions at $$ \sqrt{s} $$ s = 13 TeV with ALICE. The measurements are performed as a function of the charged-particle multiplicity ⟨d N ch / d η ⟩, which is related to the energy density produced in the collision. The results include transverse momentum...

A bstract Results on the transverse spherocity dependence of light-flavor particle production ( π , K, p, ϕ , K *0 , $$ {\textrm{K}}_{\textrm{S}}^0 $$ K S 0 , Λ, Ξ) at midrapidity in high-multiplicity pp collisions at $$ \sqrt{s} $$ s = 13 TeV were obtained with the ALICE apparatus. The transverse spherocity estimator $$ \left({S}_{\textrm{O}}^{p_{...

This Letter presents the measurement of near-side associated per-trigger yields, denoted ridge yields, from the analysis of angular correlations of charged hadrons in proton-proton collisions at s = 13 TeV . Long-range ridge yields are extracted for pairs of charged particles with a pseudorapidity difference of 1.4 < | Δ η | < 1.8 and a transverse...

We measure triangular flow relative to the reaction plane at 3 GeV center-of-mass energy in Au+Au collisions at the BNL Relativistic Heavy Ion Collider. A significant v3 signal for protons is observed, which increases for higher rapidity, higher transverse momentum, and more peripheral collisions. The triangular flow is essentially rapidity-odd wit...

The first measurement of the cross section for incoherent photonuclear production of J / ψ vector mesons as a function of the Mandelstam | t | variable is presented. The measurement was carried out with the ALICE detector at midrapidity, | y | < 0.8 , using ultraperipheral collisions of Pb nuclei at a center-of-mass energy per nucleon pair of s NN...

Angular distributions of charged particles relative to jet axes are studied in sNN=200 GeV Au+Au collisions as a function of the jet orientation with respect to the event plane. This differential study tests the expected path-length dependence of energy loss experienced by a hard-scattered parton as it traverses the hot and dense medium formed in h...

The production of K * ( 892 ) ± meson resonance is measured at midrapidity ( | y | < 0.5 ) in Pb − Pb collisions at s N N = 5.02 TeV using the ALICE detector at the CERN Large Hadron Collider. The resonance is reconstructed via its hadronic decay channel K * ( 892 ) ± → K S 0 π ± . The transverse momentum distributions are obtained for various cent...

A bstract Long- and short-range correlations for pairs of charged particles are studied via two-particle angular correlations in pp collisions at $$ \sqrt{s} $$ s = 13 TeV and p–Pb collisions at $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 5 . 02 TeV. The correlation functions are measured as a function of relative azimuthal angle ∆ φ and pseudorapidity sep...

The deconfined quark-gluon plasma (QGP) created in relativistic heavy-ion collisions enables the exploration of the fundamental properties of matter under extreme conditions. Noncentral collisions can produce strong magnetic fields on the order of 10 18 G , which offers a probe into the electrical conductivity of the QGP. In particular, quarks and...

Collective behavior has been observed in high-energy heavy-ion collisions for several decades. Collectivity is driven by the high particle multiplicities that are produced in these collisions. At the CERN Large Hadron Collider (LHC), features of collectivity have also been seen in high-multiplicity proton-proton collisions that can attain particle...

The first measurements of K * ( 892 ) 0 resonance production as a function of charged-particle multiplicity in Xe-Xe collisions at s N N = 5.44 TeV and p p collisions at s = 5.02 TeV using the ALICE detector are presented. The resonance is reconstructed at midrapidity ( | y | < 0.5) using the hadronic decay channel K * 0 → K ± π ∓ . Measurements of...

The production of the ψ ( 2 S ) charmonium state was measured with ALICE in Pb-Pb collisions at s NN = 5.02 TeV , in the dimuon decay channel. A significant signal was observed for the first time at LHC energies down to zero transverse momentum, at forward rapidity ( 2.5 < y < 4 ). The measurement of the ratio of the inclusive production cross sect...

The longitudinal and transverse spin transfers to Λ ( Λ ¯ ) hyperons in polarized proton-proton collisions are expected to be sensitive to the helicity and transversity distributions, respectively, of (anti)strange quarks in the proton, and to the corresponding polarized fragmentation functions. We report improved measurements of the longitudinal s...

A bstract Measurements of the production cross sections of prompt D ⁰ , D ⁺ , D *+ , $$ {\textrm{D}}_{\textrm{s}}^{+} $$ D s + , $$ {\Lambda}_{\textrm{c}}^{+} $$ Λ c + , and $$ {\Xi}_{\textrm{c}}^{+} $$ Ξ c + charm hadrons at midrapidity in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV with the ALICE detector are presented. The D-meson cros...

A bstract The Chiral Magnetic Wave (CMW) phenomenon is essential to provide insights into the strong interaction in QCD, the properties of the quark-gluon plasma, and the topological characteristics of the early universe, offering a deeper understanding of fundamental physics in high-energy collisions. Measurements of the charge-dependent anisotrop...

The production cross sections of D0 and Λc+ hadrons originating from beauty-hadron decays (i.e., nonprompt) were measured for the first time at midrapidity (|y|<0.5) by the ALICE Collaboration in proton-proton collisions at a center-of-mass energy s=13 TeV. They are described within uncertainties by perturbative QCD calculations employing the fragm...

The polarization of Λ and Λ¯ hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sNN=200 GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of t...

Understanding the role of parton mass and Casimir color factors in the quantum chromodynamics parton shower represents an important step in characterizing the emission properties of heavy quarks. Recent experimental advances in jet substructure techniques have provided the opportunity to isolate and characterize gluon emissions from heavy quarks. I...

Measurements of the elliptic flow coefficient relative to the collision plane defined by the spectator neutrons v2{ΨSP} in collisions of Pb ions at center-of-mass energy per nucleon–nucleon pair sNN=2.76 TeV and Xe ions at sNN=5.44 TeV are reported. The results are presented for charged particles produced at midrapidity as a function of centrality...

A bstract The cross section for coherent photonuclear production of J/ ψ is presented as a function of the electromagnetic dissociation (EMD) of Pb. The measurement is performed with the ALICE detector in ultra-peripheral Pb-Pb collisions at a centre-of-mass energy per nucleon pair of $$ \sqrt{{\textrm{s}}_{\textrm{NN}}} $$ s NN = 5.02 TeV. Cross s...

A bstract The fractions of non-prompt (i.e. originating from beauty-hadron decays) D ⁰ and D ⁺ mesons with respect to the inclusive yield are measured as a function of the charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV with the ALICE detector at the LHC. The results are reported in...

The first experimental information on the strong interaction between Λ and Ξ− strange baryons is presented in this Letter. The correlation function of Λ–Ξ− and Λ‾–Ξ‾+ pairs produced in high-multiplicity proton–proton (pp) collisions at s=13 TeV at the LHC is measured as a function of the relative momentum of the pair. The femtoscopy method is used...

DOI:https://doi.org/10.1103/PhysRevLett.131.089901

A bstract Measurements of the production of electrons from heavy-flavour hadron decays in pp collisions at $$ \sqrt{s} $$ s = 13 TeV at midrapidity with the ALICE detector are presented down to a transverse momentum ( p T ) of 0.2 GeV/ c and up to p T = 35 GeV/ c , which is the largest momentum range probed for inclusive electron measurements in AL...

The transverse-momentum (p_{T}) spectra and coalescence parameters B_{2} of (anti)deuterons are measured in p-p collisions at sqrt[s]=13 TeV for the first time in and out of jets. In this measurement, the direction of the leading particle with the highest p_{T} in the event (p_{T}^{lead}>5 GeV/c) is used as an approximation for the jet axis. The ev...

In relativistic heavy-ion collisions, a global spin polarization, PH, of Λ and Λ¯ hyperons along the direction of the system angular momentum was discovered and measured across a broad range of collision energies and demonstrated a trend of increasing PH with decreasing sNN. A splitting between Λ and Λ¯ polarization may be possible due to their dif...

A bstract This article reports measurements of the angle between differently defined jet axes in pp collisions at $$ \sqrt{s} $$ s = 5 . 02 TeV carried out by the ALICE Collaboration. Charged particles at midrapidity are clustered into jets with resolution parameters R = 0 . 2 and 0.4. The jet axis, before and after Soft Drop grooming, is compared...

Global polarizations (P) of Λ (Λ¯) hyperons have been observed in noncentral heavy-ion collisions. The strong magnetic field primarily created by the spectator protons in such collisions would split the Λ and Λ¯ global polarizations (ΔP=PΛ−PΛ¯<0). Additionally, quantum chromodynamics predicts topological charge fluctuations in vacuum, resulting in...

The chiral magnetic wave (CMW) has been theorized to propagate in the deconfined nuclear medium formed in high-energy heavy-ion collisions and to cause a difference in elliptic flow (v2) between negatively and positively charged hadrons. Experimental data consistent with the CMW have been reported by the STAR Collaboration at the Relativistic Heavy...

A bstract We report a new measurement of the production of electrons from open heavy-flavor hadron decays (HFEs) at mid-rapidity (| y | < 0.7) in Au+Au collisions at $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 200 GeV. Invariant yields of HFEs are measured for the transverse momentum range of 3 . 5 < p T < 9 GeV/ c in various configurations of the collisio...

A bstract Production of inclusive charmonia in pp collisions at center-of-mass energy of $$ \sqrt{s} $$ s = 13 TeV and p–Pb collisions at center-of-mass energy per nucleon pair of $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 8 . 16 TeV is studied as a function of charged-particle pseudorapidity density with ALICE. Ground and excited charmonium states ( J/ψ...

A bstract The measurement of the production of charm jets, identified by the presence of a D ⁰ meson in the jet constituents, is presented in proton–proton collisions at centre-of-mass energies of $$ \sqrt{s} $$ s = 5.02 and 13 TeV with the ALICE detector at the CERN LHC. The D ⁰ mesons were reconstructed from their hadronic decay D ⁰ → K − π ⁺ and...

A bstract The production of π ± , K ± , and $$ \left(\overline{\textrm{p}}\right)\textrm{p} $$ p ¯ p is measured in pp collisions at $$ \sqrt{s} $$ s = 13 TeV in different topological regions of the events. Particle transverse momentum ( p T ) spectra are measured in the “toward”, “transverse”, and “away” angular regions defined with respect to the...

A bstract The first measurement of the e ⁺ e − pair production at low lepton pair transverse momentum ( p T , ee ) and low invariant mass ( m ee ) in non-central Pb–Pb collisions at $$ {\sqrt{s}}_{\textrm{NN}} $$ s NN = 5 . 02 TeV at the LHC is presented. The dielectron production is studied with the ALICE detector at midrapidity ( |η e | < 0 . 8)...

We report systematic measurements of dielectron (e+e−) invariant-mass Mee spectra at midrapidity in Au+Au collisions at sNN = 27, 39, and 62.4 GeV taken with the STAR detector at the Relativistic Heavy Ion Collider. For all energies studied, a significant excess yield of dielectrons is observed in the low-mass region (0.40<Mee<0.75 MeV/c2) compared...

A bstract The first measurements of elliptic flow of π ± , K ± , $$ \textrm{p}+\overline{\textrm{p}} $$ p + p ¯ , $$ {\textrm{K}}_{\textrm{S}}^0 $$ K S 0 , $$ \Lambda +\overline{\Lambda} $$ Λ + Λ ¯ , ϕ , $$ {\Xi}^{-}+{\overline{\Xi}}^{+} $$ Ξ − + Ξ ¯ + , and $$ {\varOmega}^{-}+{\overline{\varOmega}}^{+} $$ Ω − + Ω ¯ + using multiparticle cumulants...

We report the triton (t) production in midrapidity (|y|<0.5) Au+Au collisions at sNN=7.7–200 GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider. The nuclear compound yield ratio (Nt×Np/Nd2), which is predicted to be sensitive to the fluctuation of local neutron density, is observe...

The production of K*(892)0and ϕ(1020)resonances has been measured in p-Pb collisions at sNN = 8.16 TeV using the ALICE detector. Resonances are reconstructed via their hadronic decay channels in the rapidity interval −0.5 < y < 0 and the transverse momentum spectra are measured for various multiplicity classes up to pT = 20 GeV/c for K*(892)0and pT...

The production of the W± bosons measured in p–Pb collisions at a centre-of-mass energy per nucleon–nucleon collision \( \sqrt{s_{\textrm{NN}}} \) = 8.16 TeV and Pb–Pb collisions at \( \sqrt{s_{\textrm{NN}}} \) = 5.02 TeV with ALICE at the LHC is presented. The W± bosons are measured via their muonic decay channel, with the muon reconstructed in the...

DOI:https://doi.org/10.1103/PhysRevC.107.049903

Measurements of the production of electrons from heavy-flavour hadron decays in pp collisions at $\sqrt{s} = 13$ TeV at midrapidity with the ALICE detector are presented down to a transverse momentum ($p_{\rm T}$) of 0.2 GeV$/c$ and up to $p_{\rm T} = 35$ GeV$/c$, which is the largest momentum range probed for inclusive electron measurements in ALI...

The polarization of $\Lambda$ and $\bar{\Lambda}$ hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at $\sqrt{s_{NN}}$ = 200 GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial densit...

We report on measurements of sequential ϒ suppression in Au+Au collisions at sNN=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%–60% centrality class, the nuclear modification factors (RAA), which quantify the level of yield suppression in heavy-ion collis...

We report the measurement of K*0 meson at midrapidity (|y|< 1.0) in Au+Au collisions at sNN=7.7, 11.5, 14.5, 19.6, 27, and 39 GeV collected by the STAR experiment during the Relativistic Heavy Ion Collider (RHIC) beam energy scan program. The transverse momentum spectra, yield, and average transverse momentum of K*0 are presented as functions of co...

A decisive experimental test of the Chiral Magnetic Effect (CME) is considered one of the major scientific goals at the Relativistic Heavy-Ion Collider (RHIC) towards understanding the nontrivial topological fluctuations of the Quantum Chromodynamics vacuum. In heavy-ion collisions, the CME is expected to result in a charge separation phenomenon ac...

Azimuthal anisotropy of produced particles is one of the most important observables used to access the collective properties of the expanding medium created in relativistic heavy-ion collisions. In this paper, we present second (v2) and third (v3) order azimuthal anisotropies of KS0, ϕ, Λ, Ξ, and Ω at midrapidity (|y|<1) in Au+Au collisions at sNN=...

We report a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at sNN = 3 GeV measured by the STAR experiment. Protons are identified within the rapidity (y) and transverse momentum (pT) region −0.9<y<0 and 0.4<pT<2.0 GeV/c in the center-of-mass frame. A systemat...

The linear and mode-coupled contributions to higher-order anisotropic flow are presented for Au+Au collisions at sNN = 27, 39, 54.4, and 200 GeV and compared to similar measurements for Pb+Pb collisions at the Large Hadron Collider (LHC). The coefficients and the flow harmonics' correlations, which characterize the linear and mode-coupled response...

The production of prompt Λc+ baryons at midrapidity (|y