Showing papers by "J. Pluta published in 2022"
TL;DR: In this paper , a blind analysis of a large data sample of approximately 3.8 billion isobar collisions of Ru4496+Ru4496 and Zr4096+Zr 4096 at sNN=200 GeV was performed.
Abstract: The chiral magnetic effect (CME) is predicted to occur as a consequence of a local violation of P and CP symmetries of the strong interaction amidst a strong electromagnetic field generated in relativistic heavy-ion collisions. Experimental manifestation of the CME involves a separation of positively and negatively charged hadrons along the direction of the magnetic field. Previous measurements of the CME-sensitive charge-separation observables remain inconclusive because of large background contributions. To better control the influence of signal and backgrounds, the STAR Collaboration performed a blind analysis of a large data sample of approximately 3.8 billion isobar collisions of Ru4496+Ru4496 and Zr4096+Zr4096 at sNN=200 GeV. Prior to the blind analysis, the CME signatures are predefined as a significant excess of the CME-sensitive observables in Ru+Ru collisions over those in Zr+Zr collisions, owing to a larger magnetic field in the former. A precision down to 0.4% is achieved, as anticipated, in the relative magnitudes of the pertinent observables between the two isobar systems. Observed differences in the multiplicity and flow harmonics at the matching centrality indicate that the magnitude of the CME background is different between the two species. No CME signature that satisfies the predefined criteria has been observed in isobar collisions in this blind analysis.20 MoreReceived 31 August 2021Accepted 7 December 2021DOI:https://doi.org/10.1103/PhysRevC.105.014901©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle correlations & fluctuationsQuark-gluon plasmaRelativistic heavy-ion collisionsNuclear Physics
103 citations
TL;DR: In this paper , the authors provide an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input.
Abstract: The Nuclotron-base Ion Collider fAcility (NICA) is under construction at the Joint Institute for Nuclear Research (JINR), with commissioning of the facility expected in late 2022. The Multi-Purpose Detector (MPD) has been designed to operate at NICA and its components are currently in production. The detector is expected to be ready for data taking with the first beams from NICA. This document provides an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input. It also provides a detailed description of the MPD set-up, including its various subsystems as well as its support and computing infrastructures. Selected performance studies for particular physics measurements at MPD are presented and discussed in the context of existing data and theoretical expectations.
21 citations
TL;DR: In this article , the authors report on the measurements of directed flow and elliptic flow for hadrons from Au+Au collisions at 3.4 and 6.4, respectively.
20 citations
TL;DR: In this article , the authors provide an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input.
Abstract: The Nuclotron-base Ion Collider fAcility (NICA) is under construction at the Joint Institute for Nuclear Research (JINR), with commissioning of the facility expected in late 2022. The Multi-Purpose Detector (MPD) has been designed to operate at NICA and its components are currently in production. The detector is expected to be ready for data taking with the first beams from NICA. This document provides an overview of the landscape of the investigation of the QCD phase diagram in the region of maximum baryonic density, where NICA and MPD will be able to provide significant and unique input. It also provides a detailed description of the MPD set-up, including its various subsystems as well as its support and computing infrastructures. Selected performance studies for particular physics measurements at MPD are presented and discussed in the context of existing data and theoretical expectations.
17 citations
TL;DR: In this article , the authors reported precision measurements of hypernuclei lifetimes obtained from Au+Au collisions at 3.0 GeV and 7.2 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider.
Abstract: We report precision measurements of hypernuclei _{Λ}^{3}H and _{Λ}^{4}H lifetimes obtained from Au+Au collisions at sqrt[s_{NN}]=3.0 GeV and 7.2 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider, and the first measurement of _{Λ}^{3}H and _{Λ}^{4}H midrapidity yields in Au+Au collisions at sqrt[s_{NN}]=3.0 GeV. _{Λ}^{3}H and _{Λ}^{4}H, being the two simplest bound states composed of hyperons and nucleons, are cornerstones in the field of hypernuclear physics. Their lifetimes are measured to be 221±15(stat)±19(syst) ps for _{Λ}^{3}H and 218±6(stat)±13(syst) ps for _{Λ}^{4}H. The p_{T}-integrated yields of _{Λ}^{3}H and _{Λ}^{4}H are presented in different centrality and rapidity intervals. It is observed that the shape of the rapidity distribution of _{Λ}^{4}H is different for 0%-10% and 10%-50% centrality collisions. Thermal model calculations, using the canonical ensemble for strangeness, describes the _{Λ}^{3}H yield well, while underestimating the _{Λ}^{4}H yield. Transport models, combining baryonic mean-field and coalescence (jam) or utilizing dynamical cluster formation via baryonic interactions (phqmd) for light nuclei and hypernuclei production, approximately describe the measured _{Λ}^{3}H and _{Λ}^{4}H yields. Our measurements provide means to precisely assess our understanding of the fundamental baryonic interactions with strange quarks, which can impact our understanding of more complicated systems involving hyperons, such as the interior of neutron stars or exotic hypernuclei.
17 citations
TL;DR: In this paper , it was shown that in relativistic heavy-ion collisions, where quarks and gluons are set free over an extended volume, two species of produced vector (spin-1) mesons emerge with a surprising pattern of global spin alignment.
Abstract: Notwithstanding decades of progress since Yukawa first developed a description of the force between nucleons in terms of meson exchange, a full understanding of the strong interaction remains a major challenge in modern science. One remaining difficulty arises from the non-perturbative nature of the strong force, which leads to the phenomenon of quark confinement at distances on the order of the size of the proton. Here we show that in relativistic heavy-ion collisions, where quarks and gluons are set free over an extended volume, two species of produced vector (spin-1) mesons, namely $\phi$ and $K^{*0}$, emerge with a surprising pattern of global spin alignment. In particular, the global spin alignment for $\phi$ is unexpectedly large, while that for $K^{*0}$ is consistent with zero. The observed spin-alignment pattern and magnitude for the $\phi$ cannot be explained by conventional mechanisms, while a model with a connection to strong force fields, i.e. an effective proxy description within the Standard Model and Quantum Chromodynamics, accommodates the current data. This connection, if fully established, will open a potential new avenue for studying the behaviour of strong force fields.
15 citations
TL;DR: In this article , the authors measured the charge separation in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider.
Abstract: The chiral magnetic effect (CME) refers to charge separation along a strong magnetic field due to imbalanced chirality of quarks in local parity and charge-parity violating domains in quantum chromodynamics. The experimental measurement of the charge separation is made difficult by the presence of a major background from elliptic azimuthal anisotropy. This background and the CME signal have different sensitivities to the spectator and participant planes, and could thus be determined by measurements with respect to these planes. We report such measurements in Au+Au collisions at a nucleon-nucleon center-of-mass energy of 200 GeV at the Relativistic Heavy-Ion Collider. It is found that the charge separation, with the flow background removed, is consistent with zero in peripheral (large impact parameter) collisions. Some indication of finite CME signals is seen in midcentral (intermediate impact parameter) collisions. Significant residual background effects may, however, still be present.
14 citations
TL;DR: In this paper , a linearly polarized photon was used in diffractive photoproduction to observe a unique spin interference pattern in the angular distribution of ρ0 → π+π− decays.
Abstract: A linearly polarized photon can be quantized from the Lorentz-boosted electromagnetic field of a nucleus traveling at ultrarelativistic speed. When two relativistic heavy nuclei pass one another at a distance of a few nuclear radii, the photon from one nucleus may interact through a virtual quark-antiquark pair with gluons from the other nucleus, forming a short-lived vector meson (e.g., ρ0). In this experiment, the polarization was used in diffractive photoproduction to observe a unique spin interference pattern in the angular distribution of ρ0 → π+π− decays. The observed interference is a result of an overlap of two wave functions at a distance an order of magnitude larger than the ρ0 travel distance within its lifetime. The strong-interaction nuclear radii were extracted from these diffractive interactions and found to be 6.53 ± 0.06 fm (197Au) and 7.29 ± 0.08 fm (238U), larger than the nuclear charge radii. The observable is demonstrated to be sensitive to the nuclear geometry and quantum interference of nonidentical particles.
12 citations
TL;DR: In this paper , the first multi-differential measurements of strange hadrons of $K^{-}, $K^+K^-$ yields as well as the ratios of $\phi/K^$ and $Xi^-$ in Au+Au collisions with the STAR experiment at RHIC were reported.
10 citations
TL;DR: In this paper , the first measurement of J/ψ photoproduction off the deuteron in UPCs at the center-of-mass energy sNN=200 GeV in d+Au collisions is reported.
Abstract: Understanding gluon density distributions and how they are modified in nuclei are among the most important goals in nuclear physics. In recent years, diffractive vector meson production measured in ultraperipheral collisions (UPCs) at heavy-ion colliders has provided a new tool for probing the gluon density. In this Letter, we report the first measurement of J/ψ photoproduction off the deuteron in UPCs at the center-of-mass energy sNN=200 GeV in d+Au collisions. The differential cross section as a function of momentum transfer −t is measured. In addition, data with a neutron tagged in the deuteron-going zero-degree calorimeter is investigated for the first time, which is found to be consistent with the expectation of incoherent diffractive scattering at low momentum transfer. Theoretical predictions based on the color glass condensate saturation model and the leading twist approximation nuclear shadowing model are compared with the data quantitatively. A better agreement with the saturation model has been observed. With the current measurement, the results are found to be directly sensitive to the gluon density distribution of the deuteron and the deuteron breakup process, which provides insights into the nuclear gluonic structure.Received 15 September 2021Revised 18 January 2022Accepted 25 February 2022DOI:https://doi.org/10.1103/PhysRevLett.128.122303© 2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasPhotonuclear reactionsRelativistic heavy-ion collisionsNuclear Physics
5 citations
TL;DR: In this article , the beam energy and collision centrality dependence of fifth and sixth order cumulants (C5, C6}) and factorial cumulant (κ_{5, κ_{6}) of net-proton and proton number distributions, from center-of-mass energy (sqrt[s_{NN}]) 3.GeV to 200 ǫGeV Au+Au collisions at RHIC, were reported.
Abstract: We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C_{5}, C_{6}) and factorial cumulants (κ_{5}, κ_{6}) of net-proton and proton number distributions, from center-of-mass energy (sqrt[s_{NN}]) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C_{6}/C_{2} for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, μ_{B}≤110 MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κ_{n}, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, μ_{B}∼750 MeV at sqrt[s_{NN}]=3 GeV is starkly different from those at vanishing μ_{B}∼24 MeV at sqrt[s_{NN}]=200 GeV and higher collision energies.
23 May 2022
TL;DR: In this article , the longitudinal double-spin asymmetry was measured at the same center-of-mass energy that probes the polarized gluon distribution function at partonic momentum fraction 0.015≲x≲0.25.
Abstract: We report measurements of the longitudinal double-spin asymmetry, ALL, for inclusive jet and dijet production in polarized proton-proton collisions at midrapidity and center-of-mass energy s=510 GeV, using the high luminosity data sample collected by the STAR experiment in 2013. These measurements complement and improve the precision of previous STAR measurements at the same center-of-mass energy that probe the polarized gluon distribution function at partonic momentum fraction 0.015≲x≲0.25. The dijet asymmetries are separated into four jet-pair topologies, which provide further constraints on the x dependence of the polarized gluon distribution function. These measurements are in agreement with previous STAR measurements and with predictions from current next-to-leading-order global analyses. They provide more precise data at low dijet invariant mass that will better constrain the shape of the polarized gluon distribution function of the proton.Received 21 October 2021Accepted 4 April 2022DOI:https://doi.org/10.1103/PhysRevD.105.092011Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasQuark & gluon jetsPhysical SystemsGluonsPropertiesSpinTechniquesHadron collidersParticles & FieldsNuclear Physics
TL;DR: In this paper , an event-shape-engineering technique is deployed to determine the background shape as a function of the π-invariant mass of the particle in relativistic heavy-ion collisions at RHIC.
Abstract: Quark interactions with topological gluon configurations can induce local chirality imbalance and parity violation in quantum chromodynamics, which can lead to the chiral magnetic effect (CME) -- an electric charge separation along the strong magnetic field in relativistic heavy-ion collisions. The CME-sensitive azimuthal correlator observable ($\Delta\gamma$) is contaminated by background arising, in part, from resonance decays coupled with elliptic anisotropy ($v_{2}$). We report here differential measurements of the correlator as a function of the pair invariant mass ($m_{\rm inv}$) in 20-50\% centrality Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$= 200 GeV by the STAR experiment at RHIC. Strong resonance background contributions to $\Delta\gamma$ are observed. At large $m_{\rm inv}$ where this background is significantly reduced, the $\Delta\gamma$ value is found to be significantly smaller. An event-shape-engineering technique is deployed to determine the $v_{2}$ background shape as a function of $m_{\rm inv}$. We extract a $v_2$-independent and $m_{\rm inv}$-averaged signal $\Delta\gamma_{\rm sig}$ = (0.03 $\pm$ 0.06 $\pm$ 0.08) $\times10^{-4}$, or $(2\pm4\pm5)\%$ of the inclusive $\Delta\gamma(m_{\rm inv}>0.4$ GeV/$c^2$)$ =(1.58 \pm 0.02 \pm 0.02) \times10^{-4}$, within pion $p_{T}$ = 0.2 - 0.8~\gevc and averaged over pseudorapidity ranges of $-1 < \eta < -0.05$ and $0.05 < \eta < 1$. This represents an upper limit of $0.23\times10^{-4}$, or $15\%$ of the inclusive result, at $95\%$ confidence level for the $m_{\rm inv}$-integrated CME contribution.
TL;DR: In this article , the STAR collaboration presented jet substructure measurements related to both the momentum fraction and the opening angle within jets in p+p and Au+Au collisions at sNN =200GeV.
Abstract: The STAR collaboration presents jet substructure measurements related to both the momentum fraction and the opening angle within jets in p+p and Au+Au collisions at sNN =200GeV. The substructure observables include SoftDrop groomed momentum fraction (zg), groomed jet radius (Rg), and subjet momentum fraction (zSJ) and opening angle (θSJ). The latter observable is introduced for the first time. Fully corrected subjet measurements are presented for p+p collisions and are compared to leading-order Monte Carlo models. The subjet θSJ distributions reflect the jets leading opening angle and are utilized as a proxy for the resolution scale of the medium in Au+Au collisions. We compare data from Au+Au collisions to those from p+p which are embedded in minimum-bias Au+Au events in order to include the effects of detector smearing and the heavy-ion collision underlying event. The subjet observables are shown to be more robust to the background than zg and Rg. We observe no significant modifications of the subjet observables within the two highest-energy, back-to-back jets, resulting in a distribution of opening angles and the splittings that are vacuumlike. We also report measurements of the differential dijet momentum imbalance (AJ) for jets of varying θSJ. We find no qualitative differences in energy loss signatures for varying angular scales in the range 0.1< θSJ<0.3, leading to the possible interpretation that energy loss in this population of high-momentum dijet pairs, is due to soft medium-induced gluon radiation from a single color charge as it traverses the medium.4 MoreReceived 20 September 2021Accepted 11 January 2022DOI:https://doi.org/10.1103/PhysRevC.105.044906©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasJets & heavy flavor physicsQuark & gluon jetsQuark-gluon plasmaRelativistic heavy-ion collisionsNuclear Physics
TL;DR: In this paper , the authors present a low energy search for the Chiral Magnetic Effect (CME) in Au+Au collisions at the Relativistic Heavy-Ion Collider (RHIC) towards understanding the nontrivial topological fluctuations of the Quantum Chromodynamics vacuum.
TL;DR: In this paper , the mass and binding energy of a relativistic heavy-ion system with atomic number A = 4 were measured to be 2.22 and 2.38, respectively.
28 Oct 2022
TL;DR: In this article , the authors measured the transverse single-spin asymmetries of jets and identified hadrons within jets' production at midrapidity from transversely polarized $pp$ collisions at 200 GeV, using data recorded in 2012 and 2015.
Abstract: The STAR Collaboration reports measurements of the transverse single-spin asymmetries, $A_N$, for inclusive jets and identified `hadrons within jets' production at midrapidity from transversely polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV, based on data recorded in 2012 and 2015. The inclusive jet asymmetry measurements include $A_N$ for inclusive jets and $A_N$ for jets containing a charged pion carrying a momentum fraction $z>0.3$ of the jet momentum. The identified hadron within jet asymmetry measurements include the Collins effect for charged pions, kaons and protons, and the Collins-like effect for charged pions. The measured asymmetries are determined for several distinct kinematic regions, characterized by the jet transverse momentum $p_{T}$ and pseudorapidity $\eta$, as well as the hadron momentum fraction $z$ and momentum transverse to the jet axis $j_{T}$. These results probe higher momentum scales ($Q^{2}$ up to $\sim$\,900 GeV$^{2}$) than current, semi-inclusive deep inelastic scattering measurements, and they provide new constraints on quark transversity in the proton and enable tests of evolution, universality and factorization breaking in the transverse-momentum-dependent formalism.
14 Mar 2022
TL;DR: In this paper , high-precision measurements of elliptic, triangular, and quadrangular flow at mid-rapidity were obtained for identified hadrons, and the results were compared to several viscous hydrodynamic calculations with varying initial conditions, and could serve as an additional constraint to the development of hydrodynamynamic models.
Abstract: We present high-precision measurements of elliptic, triangular, and quadrangular flow $v_{2}$, $v_{3}$, and $v_{4}$, respectively, at midrapidity ($|\eta|<1.0$) for identified hadrons $\pi$, $p$, $K$, $\varphi$, $K_s$, $\Lambda$ as a function of centrality and transverse momentum in Au+Au collisions at the center-of-mass energy $\sqrt{s_{\rm NN}}=$ 200 GeV. We observe similar $v_{n}$ trends between light and strange mesons which indicates that the heavier strange quarks flow as strongly as the lighter up and down quarks. The number-of-constituent-quark scaling for $v_{2}$, $v_{3}$, and $v_{4}$ is found to hold within statistical uncertainty for 0-10$\%$, 10-40$\%$ and 40-80$\%$ collision centrality intervals. The results are compared to several viscous hydrodynamic calculations with varying initial conditions, and could serve as an additional constraint to the development of hydrodynamic models.
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24 May 2022
TL;DR: In this paper , the authors measured the transverse single-spin asymmetries of jets and identified hadrons within jets' production at midrapidity from transversely polarized $pp$ collisions at 200 GeV.
Abstract: The STAR Collaboration reports measurements of the transverse single-spin asymmetries, $A_N$, for inclusive jets and identified `hadrons within jets' production at midrapidity from transversely polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV, based on data recorded in 2012 and 2015. The inclusive jet asymmetry measurements include $A_N$ for inclusive jets and $A_N$ for jets containing a charged pion carrying a momentum fraction $z>0.3$ of the jet momentum. The identified hadron within jet asymmetry measurements include the Collins effect for charged pions, kaons and protons, and the Collins-like effect for charged pions. The measured asymmetries are determined for several distinct kinematic regions, characterized by the jet transverse momentum $p_{T}$ and pseudorapidity $\eta$, as well as the hadron momentum fraction $z$ and momentum transverse to the jet axis $j_{T}$. These results probe higher momentum scales ($Q^{2}$ up to $\sim$\,900 GeV$^{2}$) than current, semi-inclusive deep inelastic scattering measurements, and they provide new constraints on quark transversity in the proton and enable tests of evolution, universality and factorization breaking in the transverse-momentum-dependent formalism.
TL;DR: In this article , the authors present a model for particle correlations and fluctuations in QCD phase transitions and relativistic heavy-ion collisions in the context of nuclear physics, which they call PHYSH.
Abstract: Received 22 October 2021DOI:https://doi.org/10.1103/PhysRevC.105.029901©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle correlations & fluctuationsQCD phase transitionsRelativistic heavy-ion collisionsNuclear Physics
23 Feb 2022
TL;DR: In this paper , a new measurement of the production cross section for inclusive electrons from open heavy-flavor hadron decays as a function of transverse momentum (pT) at midrapidity (|y| < 0.7) in p+p collisions at s=200 GeV.
Abstract: We report a new measurement of the production cross section for inclusive electrons from open heavy-flavor hadron decays as a function of transverse momentum (pT) at midrapidity (|y|<0.7) in p+p collisions at s=200 GeV. The result is presented for 2.5
TL;DR: In this paper , the mass and binding energy of a relativistic heavy-ion system with atomic number A = 4 were measured to be 2.22 and 2.38, respectively.
TL;DR: In this article , the authors report on measurements of sequential ϒ suppression in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels.
Abstract: We report on measurements of sequential ϒ suppression in Au+Au collisions at sqrt[s_{NN}]=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 (R_{AA}), which quantify the level of yield suppression in heavy-ion collisions compared to p+p collisions, for ϒ(1S) and ϒ(2S) are 0.40±0.03(stat)±0.03(sys)±0.09(norm) and 0.26±0.08(stat)±0.02(sys)±0.06(norm), respectively, while the upper limit of the ϒ(3S) R_{AA} is 0.17 at a 95% confidence level. This provides experimental evidence that the ϒ(3S) is significantly more suppressed than the ϒ(1S) at RHIC. The level of suppression for ϒ(1S) is comparable to that observed at the much higher collision energy at the Large Hadron Collider. These results point to the creation of a medium at RHIC whose temperature is sufficiently high to strongly suppress excited ϒ states.
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06 Oct 2022
TL;DR: In this paper , the authors reported the measurement of the meson at midrapidity (y|y|<$ 1.0) in Au+Au collisions at the STAR experiment during the RHIC beam energy scan (BES) program.
Abstract: We report the measurement of $K^{*0}$ meson at midrapidity ($|y|<$ 1.0) in Au+Au collisions at $\sqrt{s_{\rm NN}}$~=~7.7, 11.5, 14.5, 19.6, 27 and 39 GeV collected by the STAR experiment during the RHIC beam energy scan (BES) program. The transverse momentum spectra, yield, and average transverse momentum of $K^{*0}$ are presented as functions of collision centrality and beam energy. The $K^{*0}/K$ yield ratios are presented for different collision centrality intervals and beam energies. The $K^{*0}/K$ ratio in heavy-ion collisions are observed to be smaller than that in small system collisions (e+e and p+p). The $K^{*0}/K$ ratio follows a similar centrality dependence to that observed in previous RHIC and LHC measurements. The data favor the scenario of the dominance of hadronic re-scattering over regeneration for $K^{*0}$ production in the hadronic phase of the medium.
TL;DR: In this article , the STAR detector at the Relativistic Heavy Ion Collider was used to detect central collisions at NN p ¼ 19 : 6 , 62.4, 130, and 200 GeV.
Abstract: We report K=(cid:1) fluctuations from Au þ Au collisions at ffiffiffiffiffiffiffiffi s NN p ¼ 19 : 6 , 62.4, 130, and 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider. K=(cid:1) fluctuations in central collisions show little dependence on incident energy and are on the same order as those from NA49 at the Super Proton
TL;DR: The m ultiplicity density at m idrapidity for the 5% m ost central interactions and the transverse m om entum and pseudorapidity distributions for central collisions have been studied.
Abstract: The m inim um bias m ultiplicity distribution and the transverse m om entum and pseudorapidity distributions for centralcollisions have been m easured for negative hadrons ( h (cid:0) ) in A u+ A u interactions at p s N N = 130 G eV .The m ultiplicity density at m idrapidity for the 5% m ost central interactionsis dN h (cid:0) =d(cid:17) j (cid:17) = 0 = 280 (cid:6) 1(stat) (cid:6) 20(syst),an increase perparticipantof38% relative to p (cid:22) p collisions atthe sam e energy.The m ean transverse m om entum is0 : 508 (cid:6) 0 : 012 G eV /c and is largerthan in centralPb+ Pb collisionsatlowerenergies.Thescaling
TL;DR: D.C. Adler, Z.V. Averichev, J.S. Anderson, M.J. Ljubicic, W.P. Llope, G.L. Long, R.M. Lednický, V.K. Kravtsov, K.I. Kulikov, C.G. Klein, A.R. Klyachko, H.H%.
Abstract: C. Adler, Z. Ahammed, C. Allgower, J. Amonett, B.D. Anderson, M. Anderson, G.S. Averichev, J. Balewski, O. Barannikova, L.S. Barnby, J. Baudot, S. Bekele, V.V. Belaga, R. Bellwied, J. Berger, H. Bichsel, L.C. Bland, C.O. Blyth, B.E. Bonner, A. Boucham, A. Brandin, R.V. Cadman, H. Caines, M. Calderón de la Barca Sánchez, A. Cardenas, J. Carroll, J. Castillo, M. Castro, D. Cebra, S. Chattopadhyay, M.L. Chen, Y. Chen, S.P. Chernenko, M. Cherney, A. Chikanian, B. Choi, W. Christie, J.P. Coffin, T.M. Cormier, J.G. Cramer, H.J. Crawford, M. DeMello, W.S. Deng, A.A. Derevschikov, L. Didenko, J.E. Draper, V.B. Dunin, J.C. Dunlop, V. Eckardt, L.G. Efimov, V. Emelianov, J. Engelage, G. Eppley, B. Erazmus, P. Fachini, V. Faine,E. Finch, Y. Fisyak, D. Flierl, K.J. Foley, J. Fu, N. Gagunashvili, J. Gans, L. Gaudichet, M. Germain, F. Geurts, V. Ghazikhanian, J. Grabski, O. Grachov, D. Greiner, V. Grigoriev, M. Guedon, E. Gushin, T.J. Hallman, D. Hardtke, J.W. Harris, M. Heffner, S. Heppelmann, T. Herston, B. Hippolyte, A. Hirsch, E. Hjort, G.W. Hoffmann, M. Horsley, H.Z. Huang, T.J. Humanic, H. Hümmler, G. Igo, A. Ishihara, Yu.I. Ivanshin, P. Jacobs, W.W. Jacobs, M. Janik, I. Johnson, P.G. Jones, E. Judd, M. Kaneta, M. Kaplan, D. Keane, A. Kisiel, J. Klay, S.R. Klein, A. Klyachko, A.S. Konstantinov, L. Kotchenda, A.D. Kovalenko, M. Kramer, P. Kravtsov, K. Krueger, C. Kuhn, A.I. Kulikov, G.J. Kunde, C.L. Kunz, R.Kh. Kutuev, A.A. Kuznetsov, L. Lakehal-Ayat, J. Lamas-Valverde, M.A.C. Lamont, J.M. Landgraf, S. Lange, C.P. Lansdell, B. Lasiuk, F. Laue, A. Lebedev, T. LeCompte, R. Lednický, V.M. Leontiev, M.J. LeVine, Q. Li, Q. Li, S.J. Lindenbaum, M.A. Lisa, T. Ljubicic, W.J. Llope, G. LoCurto, H. Long, R.S. Longacre, M. Lopez-Noriega, W.A. Love, D. Lynn, R. Majka, S. Margetis, L. Martin, J. Marx, H.S. Matis, Yu.A. Matulenko, T.S. McShane, F. Meissner, Yu. Melnick, A. Meschanin, M. Messer, M.L. Miller, Z. Milosevich, N.G. Minaev, J. Mitchell, V.A. Moiseenko, D. Moltz, C.F. Moore, V. Morozov, M.M. de Moura, M.G. Munhoz, G.S. Mutchler, J.M. Nelson, P. Nevski, V.A. Nikitin, L.V. Nogach, B. Norman, S.B. Nurushev, G. Odyniec, A. Ogawa, V. Okorokov, M. Oldenburg, D. Olson, G. Paic, S.U. Pandey, Y. Panebratsev, S.Y. Panitkin, A.I. Pavlinov, T. Pawlak, V. Perevoztchikov, W. Peryt, V.A Petrov, E. Platner, J. Pluta, N. Porile, J. Porter, A.M. Poskanzer, E. Potrebenikova, D. Prindle,C. Pruneau, S. Radomski, G. Rai, O. Ravel, R.L. Ray, S.V. Razin, D. Reichhold, J.G. Reid, F. Retiere, A. Ridiger, H.G. Ritter, J.B. Roberts, O.V. Rogachevski, J.L. Romero, C. Roy, D. Russ, V. Rykov, I. Sakrejda, J. Sandweiss, A.C. Saulys, I. Savin, J. Schambach, R.P. Scharenberg, N. Schmitz, L.S. Schroeder, A. Schüttauf, K. Schweda, J. Seger, D. Seliverstov, P. Seyboth, E. Shahaliev, K.E. Shestermanov, S.S. Shimanskii, V.S. Shvetcov, G. Skoro, N. Smirnov, R. Snellings, J. Sowinski, H.M. Spinka, B. Srivastava, E.J. Stephenson, R. Stock, A. Stolpovsky, M. Strikhanov, B. Stringfellow, C. Struck, A.A.P. Suaide, E. Sugarbaker, C. Suire, M. Šumbera, T.J.M. Symons, A. Szanto de Toledo, P. Szarwas, J. Takahashi, A.H. Tang, J.H. Thomas, V. Tikhomirov, T.A. Trainor, S. Trentalange, M. Tokarev, M.B. Tonjes, V. Trofimov, O. Tsai, K. Turner, T. Ullrich, D.G. Underwood, G. Van Buren, A.M. VanderMolen, A. Vanyashin, I.M. Vasilevski, A.N. Vasiliev, S.E. Vigdor, S.A. Voloshin, F. Wang, H. Ward, J.W. Watson, R. Wells, T. Wenaus, G.D. Westfall, C. Whitten Jr. , H. Wieman, R. Willson, S.W. Wissink, R. Witt, N. Xu, Z. Xu, A.E. Yakutin, E. Yamamoto, J. Yang, P. Yepes, A. Yokosawa, V.I. Yurevich, Y.V. Zanevski, I. Zborovský, H. Zhang, W.M. Zhang, R. Zoulkarneev, A.N. Zubarev
TL;DR: In this article , the relativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) have been studied using two-dimensional transverse rapidity coordinates (yT1,yT2).
Abstract: Two-particle correlation measurements projected onto two-dimensional, transverse rapidity coordinates (yT1,yT2) provide an independent, orthogonal view of the multidimensional correlation distribution that is most often studied via angular projections. As such, these independent transverse projections allow access to manifestations of dynamical fluctuations in relativistic heavy-ion collisions that angular-correlation measurements may not be sensitive to. We report nonidentified charged-particle correlations for Au+Au minimum-bias collisions at sNN=200 GeV taken by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). Correlations are presented as two-dimensional functions of transverse rapidity for like-sign, unlike-sign, and all charged-particle pairs, as well as for particle pairs whose relative azimuthal angles lie on the near-side, the away-side, or at all relative azimuth. The correlations are constructed using charged particles with transverse momentum pT≥0.15 GeV/c, pseudorapidity from −1 to 1, and azimuthal angles from −π to π. The significant correlation structures that are observed evolve smoothly with collision centrality. The major correlation features include a saddle shape plus a broad peak with maximum near yT≈3, corresponding to pT≈1.5 GeV/c. The broad peak is observed in both like- and unlike-sign charge combinations and in near- and away-side relative azimuthal angles. The all-charge, all-azimuth correlation measurements are compared with the predictions of hijing and epos to provide theoretical context for these new measurements. The results indicate that the correlations for peripheral to mid-central collisions can be approximately described as a superposition of nucleon + nucleon collisions with minimal effects from the quantum chromodynamics medium. Strong medium effects are indicated in mid- to most-central collisions.1 MoreReceived 22 April 2022Accepted 28 September 2022DOI:https://doi.org/10.1103/PhysRevC.106.044906©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasParticle correlations & fluctuationsRelativistic heavy-ion collisionsNuclear Physics
25 Apr 2022
TL;DR: In this paper , two-particle correlation measurements projected onto two-dimensional, transverse rapidity coordinates ( y T 1 , y T 2 ) are presented as 2D functions of transverse Rapidity for like-sign, unlike-sign and all charged-particles pairs, as well as for particle pairs whose relative azimuthal angles lie on the near side, the away side, or at all relative angle.
Abstract: Two-particle correlation measurements projected onto two-dimensional, transverse rapidity coordinates ( y T 1 , y T 2 ), allow access to dynamical properties of the QCD medium produced in relativistic heavy-ion collisions that angular correlation measurements are not sensitive to. We report non-identified charged-particle correlations for Au + Au minimum-bias collisions at √ s NN = 200 GeV taken by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). Correlations are presented as 2D functions of transverse rapidity for like-sign, unlike-sign and all charged-particle pairs, as well as for particle pairs whose relative azimuthal angles lie on the near-side, the away-side, or at all relative azimuth. The correlations are constructed using charged particles with transverse momentum p T ≥ 0 . 15 GeV/ c , pseudorapidity from − 1 to 1, and azimuthal angles from − π to π . The significant correlation structures that are observed evolve smoothly with collision centrality. The major correlation features include a saddle shape plus a broad peak with maximum near y T ≈ 3, corresponding to p T ≈ 1.5 GeV/ c . The broad peak is observed in both like- and unlike-sign charge combinations and in near- and away-side relative azimuthal angles. The all-charge, all-azimuth correlation measurements are compared with the theoretical predictions of hijing and epos . The results indicate that the correlations for peripheral to mid-central collisions can be approximately described as a superposition of nucleon + nucleon collisions with minimal effects from the QCD medium. Strong medium effects are indicated in mid- to most-central collisions.
DOI•
24 Sep 2022
TL;DR: In this article , a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at 3 GeV measured by the STAR experiment is reported.
Abstract: We report a measurement of cumulants and correlation functions of event-by-event proton multiplicity distributions from fixed-target Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 3 GeV measured by the STAR experiment. Protons are identified within the rapidity ($y$) and transverse momentum ($p_{\rm T}$) region $-0.9