Flow and interferometry results from Au+Au collisions at sNN =4.5 GeV
TL;DR: The beam energy scan (BES) program at the BNL Relativistic Heavy Ion Collider (RHIC) was extended to energies below sNN=7.7 GeV in 2015 by successful implementation of the fixed-target mode of operation in the STAR (Solenoidal Tracker At RHIC) experiment as discussed by the authors.
Abstract: The beam energy scan (BES) program at the BNL Relativistic Heavy Ion Collider (RHIC) was extended to energies below sNN=7.7 GeV in 2015 by successful implementation of the fixed-target mode of operation in the STAR (Solenoidal Tracker At RHIC) experiment. In this mode, ions circulate in one ring of the collider and interact with a stationary target at the entrance of the STAR time projection chamber. The first results for Au+Au collisions at sNN=4.5 GeV are presented, demonstrating good performance of all the relevant detector subsystems in fixed-target mode. Results presented here include directed and elliptic flow of identified hadrons, and radii from pion femtoscopy. The latter, together with recent HADES results, reveal a long-sought peak structure that may be caused by the system evolving through a first-order phase transition from quark-gluon plasma to the hadronic phase. Directed and elliptic flow for pions are presented for the first time at this beam energy. Pion and proton elliptic flow show behavior which hints at constituent quark scaling, and demonstrate that a definitive conclusion will be achievable using the full statistics of the ongoing second phase of BES (BES-II). In particular, BES-II to date has recorded fixed-target data sets with two orders of magnitude more events at each of nine energies between sNN=3.0 and 7.7 GeV.
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Book•
01 Dec 1984
TL;DR: In a recent review as mentioned in this paper, the authors reflect some of the shifts of emphasis that are occurring among the fields of astrophysics, nuclear physics, and elementary particle physics and discuss the role of rotational degrees of freedom in heavy-ion collisions at low and moderate energies.
Abstract: The contents of this review reflect some of the shifts of emphasis that are occurring among the fields of astrophysics, nuclear physics, and elementary particle physics. Particle physics has made great advances in the unification of the fundamental forces of nature. Discussions and planning for a next big step in accelerator-colliders are presented. The technology of superconducting magnet systems as well as the fundamental physical principles of particle accelerators are discussed. Also presented are: high-resolution electronic particle detectors; nuclear physics changes such as pion interactions within nuclei; discussion of future relativistic heavy-ion colliders; the role of rotational degrees of freedom in heavy-ion collisions at low and moderate energies; hyperon beta decays; and the analysis of materials via nuclear reaction techniques. Neutrinos, their interactions and possible masses, have an important bearing on cosmology and the matter density of the universe in addition to their inherent interest in the microscopic world and this is also examined.
676 citations
Journal Article•
TL;DR: The observation of antihypertritons—comprising an antiproton, an antineutron, and an antilambda hyperon—produced by colliding gold nuclei at high energy, have implications spanning nuclear and particle physics, astrophysics, and cosmology.
Abstract: Observation of an Antimatter Hypernucleus BIAbelev (STARCollaboration) March 10, 2010 This work was supported by the Director, Office of Science, Office of Nuclear Science of the US Department of Energy under Contract No DE-AC02- 05CH11231
156 citations
TL;DR: Abdelallah et al. as discussed by the authors reported a systematic measurement of cumulants, Cn, for net-proton, proton, and antiproton multiplicity distributions, and correlation functions, κn, in the first phase of the Beam Energy Scan (BES) program at the BNL Relativistic Heavy Ion Collider (RHIC) facility.
Abstract: Author(s): Abdallah, MS; Adam, J; Adamczyk, L; Adams, JR; Adkins, JK; Agakishiev, G; Aggarwal, I; Aggarwal, MM; Ahammed, Z; Alekseev, I; Anderson, DM; Aparin, A; Aschenauer, EC; Ashraf, MU; Atetalla, FG; Attri, A; Averichev, GS; Bairathi, V; Baker, W; Ball Cap, JG; Barish, K; Behera, A; Bellwied, R; Bhagat, P; Bhasin, A; Bielcik, J; Bielcikova, J; Bordyuzhin, IG; Brandenburg, JD; Brandin, AV; Bunzarov, I; Butterworth, J; Cai, XZ; Caines, H; Calderon De La Barca Sanchez, M; Cebra, D; Chakaberia, I; Chaloupka, P; Chan, BK; Chang, FH; Chang, Z; Chankova-Bunzarova, N; Chatterjee, A; Chattopadhyay, S; Chen, D; Chen, J; Chen, JH; Chen, X; Chen, Z; Cheng, J; Chevalier, M; Choudhury, S; Christie, W; Chu, X; Crawford, HJ; Csanad, M; Daugherity, M; Dedovich, TG; Deppner, IM; Derevschikov, AA; Dhamija, A; Di Carlo, L; Didenko, L; Dong, X; Drachenberg, JL; Dunlop, JC; Elsey, N; Engelage, J; Eppley, G; Esumi, S; Evdokimov, O; Ewigleben, A; Eyser, O; Fatemi, R; Fawzi, FM; Fazio, S; Federic, P; Fedorisin, J; Feng, CJ; Feng, Y; Filip, P; Finch, E; Fisyak, Y; Francisco, A; Fu, C | Abstract: We report a systematic measurement of cumulants, Cn, for net-proton, proton, and antiproton multiplicity distributions, and correlation functions, κn, for proton and antiproton multiplicity distributions up to the fourth order in Au+Au collisions at sNN=7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4, and 200 GeV. The Cn and κn are presented as a function of collision energy, centrality and kinematic acceptance in rapidity, y, and transverse momentum, pT. The data were taken during the first phase of the Beam Energy Scan (BES) program (2010-2017) at the BNL Relativistic Heavy Ion Collider (RHIC) facility. The measurements are carried out at midrapidity (|y|l 0.5) and transverse momentum 0.4
53 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 paper , the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at 3.0 GeV is reported, which is less than unity, the Poisson baseline.
Abstract: We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at 3.0 GeV, measured by the STAR experiment in the kinematic acceptance of rapidity ($y$) and transverse momentum ($p_{\rm T}$) within $-0.5 < y<0$ and $0.4 < p_{\rm T} <2.0 $ GeV/$c$. In the most central 0--5\% collisions, a proton cumulant ratio is measured to be $C_4/C_2=-0.85 \pm 0.09 ~(\rm stat.) \pm 0.82 ~(\rm syst.)$, which is less than unity, the Poisson baseline. The hadronic transport UrQMD model reproduces our $C_4/C_2$ in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in $C_4/C_2$ is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3\,GeV.
21 citations
References
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B. I. Abelev1, Madan M. Aggarwal2, Zubayer Ahammed3, A. V. Alakhverdyants4 +345 more•Institutions (49)
1,696 citations
"Flow and interferometry results fro..." refers background in this paper
...The integral is taken over a spherical source 5 fm in radius [57, 75]....
[...]
TL;DR: In this paper, the production of mesons containing strange quarks (KS, φ) and both singly and doubly strange baryons (,, and − + +) are measured at mid-rapidity in pp collisions at √ s = 0.9 TeV with the ALICE experiment at the LHC.
1,176 citations
"Flow and interferometry results fro..." refers background in this paper
...HADES [76], ALICE [77] and STAR [78] points include systematic errors; E895 [65] show statistical errors only....
[...]
...[77] A. Aamodt et al. (ALICE Collaboration), Phys....
[...]
...The ALICE point also corresponds to 0-5% centrality, but a slightly higher 〈kT〉 of ≈ 0.26 GeV/c....
[...]
A. Adare1, Serguei Afanasiev2, Christine Angela Aidala3, Christine Angela Aidala4 +601 more•Institutions (57)
1,161 citations
"Flow and interferometry results fro..." refers background in this paper
...Data are shown from FOPI [48, 49], E895 [45], E877 [50], CERES [51], NA49 [52], PHENIX [53], PHOBOS [54], and from the STAR collider energies [46, 47, 55–57]....
[...]
...[53] A. Adare et al. (PHENIX Collaboration), Phys....
[...]
TL;DR: A brief history of the original Glauber model is presented in this article, with emphasis on its development into the purely classical, geometric picture used for present-day data analyses.
Abstract: We review the theoretical background, experimental techniques, and phenomenology of what is known in relativistic heavy ion physics as the Glauber model, which is used to calculate geometric quantities. A brief history of the original Glauber model is presented, with emphasis on its development into the purely classical, geometric picture used for present-day data analyses. Distinctions are made between the optical limit and Monte Carlo approaches, which are often used interchangeably but have some essential differences in particular contexts. The methods used by the four RHIC experiments are compared and contrasted, although the end results are reassuringly similar for the various geometric observables. Finally, several important RHIC measurements are highlighted that rely on geometric quantities, estimated from Glauber calculations, to draw insight from experimental observables. The status and future of Glauber modeling in the next generation of heavy ion physics studies is briefly discussed.
1,042 citations
TL;DR: In this article, the Fourier expansion of azimuthal distributions is used to analyze anisotropic flow (directed, elliptic, etc.) in relativistic nuclear collisions, and formulas relevant for this approach are presented.
Abstract: The strategy and techniques for analyzing anisotropic flow (directed, elliptic, etc.) in relativistic nuclear collisions are presented. The emphasis is on the use of the Fourier expansion of azimuthal distributions. We present formulas relevant for this approach, and in particular, show how the event multiplicity enters into the event plane resolution. We also discuss the role of nonflow correlations and a method for introducing flow into a simulation.
1,003 citations