scholarly journals Recent STAR Results from Heavy-Ion and Polarized Proton Programs

2019 ◽  
Vol 222 ◽  
pp. 01004 ◽  
Author(s):  
Grigory Nigmatkulov
Keyword(s):  
Spin Asymmetry ◽  
Heavy Ion ◽  
Azimuthal Anisotropy ◽  
Relativistic Heavy Ion Collider ◽  
Longitudinal Spin ◽  
Polarized Proton ◽  
Star Experiment ◽  
Large Systems ◽  
Global And Local ◽  
Polarization Correlation

We present recent physics results from the STAR experiment at Relativistic Heavy Ion Collider (RHIC). The proceedings cover studies of azimuthal anisotropy in small and large systems, global and local hyperon polarization, correlation femtoscopy, antideuteron and J/ψ production from heavyion program as well as the measurements of longitudinal spin asymmetry from polarized proton program.

scholarly journals The Sivers asymmetry in hadronic dijet production

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Zhong-Bo Kang ◽  
Kyle Lee ◽  
Ding Yu Shao ◽  
John Terry
Keyword(s):  
Spin Asymmetry ◽  
Star Collaboration ◽  
Heavy Ion ◽  
Distribution Functions ◽  
Relativistic Heavy Ion Collider ◽  
Parton Distribution Functions ◽  
Dijet Production ◽  
Transverse Momentum Dependent ◽  
Spin Asymmetries ◽  
Polarized Proton

Abstract We study the single spin asymmetry in the back-to-back dijet production in transversely polarized proton-proton collisions. Such an asymmetry is generated by the Sivers functions in the incoming polarized proton. We propose a QCD formalism in terms of the transverse momentum dependent parton distribution functions, which allow us to resum the large logarithms that arise in the perturbative calculations. We make predictions for the Sivers asymmetry of hadronic dijet production at the kinematic region that is relevant to the experiment at the Relativistic Heavy Ion Collider (RHIC). We further compute the spin asymmetries in the selected positive and negative jet charge bins, to separate the contributions from u- and d-quark Sivers functions. We find that both the sign and size of our numerical results are roughly consistent with the preliminary results from the STAR collaboration at the RHIC.

scholarly journals Azimuthal Single-Spin Asymmetries of Charged Pions in Jets in s = 200 GeV p↑p Collisions at STAR

2016 ◽  
Vol 40 ◽  
pp. 1660040 ◽  
Author(s):  
J. Kevin Adkins ◽  
James L. Drachenberg
Keyword(s):  
Spin Asymmetry ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collider ◽  
Spin Asymmetries ◽  
Proton Collisions ◽  
Single Spin ◽  
Single Spin Asymmetries ◽  
Polarized Proton ◽  
Charged Pions ◽  
200 Gev

Single spin asymmetry measurements ([Formula: see text]) of the azimuthal distribution of charged pions inside jets produced in transversely polarized proton collisions are sensitive to the transversity distribution and the Collins fragmentation function. The STAR Detector at the Relativistic Heavy Ion Collider is well suited for these types of measurements as it is capable of full jet reconstruction and charged pion identification in the mid-rapidity region ([Formula: see text][Formula: see text][Formula: see text][Formula: see text]). We report here the first observation of Collins [Formula: see text] asymmetries in [Formula: see text] GeV [Formula: see text] collisions.

scholarly journals The STAR experiment at the relativistic heavy ion collider

1994 ◽  
Vol 566 ◽  
pp. 277-285 ◽  
Author(s):  
J.W. Harris ◽  
D.L. Adams ◽  
N. Added ◽  
S. Ahmad ◽  
S.A. Akimenko ◽  
...  
Keyword(s):  
Heavy Ion ◽  
Relativistic Heavy Ion Collider ◽  
Star Experiment

scholarly journals An Experimental Review on Heavy-Flavorv2in Heavy-Ion Collision

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Md. Nasim ◽  
Roli Esha ◽  
Huan Zhong Huang
Keyword(s):  
Hadron Collider ◽  
Large Mass ◽  
Heavy Ion ◽  
Azimuthal Anisotropy ◽  
Relativistic Heavy Ion Collisions ◽  
Dense Medium ◽  
Heavy Flavor ◽  
Relativistic Heavy Ion Collider ◽  
Ion Collisions ◽  
Ion Collision

For over a decade now, the primary purpose of relativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC) has been to study the properties of QCD matter under extreme conditions—high temperature and high density. The heavy-ion experiments at both RHIC and LHC have recorded a wealth of data in p+p, p+Pb, d+Au, Cu+Cu, Cu+Au, Au+Au, Pb+Pb, and U+U collisions at energies ranging fromsNN=7.7 GeV to 7 TeV. Heavy quarks are considered good probe to study the QCD matter created in relativistic collisions due to their very large mass and other unique properties. A precise measurement of various properties of heavy-flavor hadrons provides an insight into the fundamental properties of the hot and dense medium created in these nucleus-nucleus collisions, such as transport coefficient and thermalization and hadronization mechanisms. The main focus of this paper is to present a review on the measurements of azimuthal anisotropy of heavy-flavor hadrons and to outline the scientific opportunities in this sector due to future detector upgrade. We will mainly discuss the elliptic flow of open charmed meson (D-meson),J/ψ, and leptons from heavy-flavor decay at RHIC and LHC energy.

scholarly journals RECENT RESULTS ON HIGH-ENERGY SPIN PHENOMENA OF GLUONS AND SEA-QUARKS IN POLARIZED PROTON-PROTON COLLISIONS AT RHIC AT BNL

2014 ◽  
Vol 25 ◽  
pp. 1460033 ◽  
Author(s):  
BERND SURROW
Keyword(s):  
Heavy Ion ◽  
High Energy ◽  
Proton Spin ◽  
Relativistic Heavy Ion Collider ◽  
Spin Physics ◽  
Proton Collisions ◽  
Physics Program ◽  
Quark Spin ◽  
Polarized Proton ◽  
Spin Contribution

The STAR experiment at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is carrying out a spin physics program in high-energy polarized proton collisions at [Formula: see text] GeV and [Formula: see text] GeV to gain a deeper insight into the spin structure and dynamics of the proton. One of the main objectives of the spin physics program at RHIC is the precise determination of the polarized gluon distribution function. The STAR detector is well suited for the reconstruction of various final states involving jets, π0, π±, e± and γ, which allows to measure several different processes. Recent results suggest a gluon spin contribution to the proton spin at the same level as the quark spin contribution itself. The production of W bosons in polarized p+p collisions at [Formula: see text] GeV opens a new era in the study of the spin-flavor structure of the proton. W-(+) bosons are produced in [Formula: see text] collisions and can be detected through their leptonic decays, [Formula: see text], where only the respective charged lepton is measured. Results of W-(+) production suggest a large asymmetry between the polarization of anti-u and anti-d quarks.

scholarly journals Selected Experimental Results from Heavy-Ion Collisions at LHC

2013 ◽  
Vol 2013 ◽  
pp. 1-22 ◽  
Author(s):  
Ranbir Singh ◽  
Lokesh Kumar ◽  
Pawan Kumar Netrakanti ◽  
Bedangadas Mohanty
Keyword(s):  
Heavy Ion Collisions ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Azimuthal Anisotropy ◽  
Experimental Results ◽  
Particle Multiplicity ◽  
Charged Particle Multiplicity ◽  
Relativistic Heavy Ion Collider ◽  
Model Calculations ◽  
Ion Collisions

We review a subset of experimental results from the heavy-ion collisions at the Large Hadron Collider (LHC) facility at CERN. Excellent consistency is observed across all the experiments at the LHC (at center of mass energysNN=2.76 TeV) for the measurements such as charged particle multiplicity density, azimuthal anisotropy coefficients, and nuclear modification factor of charged hadrons. Comparison to similar measurements from the Relativistic Heavy Ion Collider (RHIC) at lower energy (sNN=200 GeV) suggests that the system formed at LHC has a higher energy density and larger system size and lives for a longer time. These measurements are compared to model calculations to obtain physical insights on the properties of matter created at the RHIC and LHC.

scholarly journals Gluon polarization measurements from longitudinally polarized proton-proton collisions at STAR

2020 ◽  
Vol 1643 (1) ◽  
pp. 012184
Author(s):  
Zilong Chang
Keyword(s):  
Spin Asymmetry ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Proton Spin ◽  
Gluon Polarization ◽  
Relativistic Heavy Ion Collider ◽  
Center Of Mass Energy ◽  
Double Spin ◽  
200 Gev ◽  
Inclusive Jet

Abstract The gluon polarization contribution to the proton spin is an integral part to solve the longstanding proton spin puzzle. At the Relativistic Heavy Ion Collider (RHIC), the STAR experiment has measured jets produced in mid-pseudo-rapidity, |η| < 1.0, and full azimuth, ϕ, from longitudinally polarized pp collisions to study the gluon polarization in the proton. At center of mass energies s = 200 and 510 GeV, jet production is dominated by hard QCD scattering processes such as gluon-gluon (gg) and quark-gluon (qg), thus making the longitudinal double-spin asymmetry (ALL ) sensitive to the gluon polarization. Early STAR inclusive jet ALL results at s = 200 GeV provided the first evidence of the non-zero gluon polarization at momentum fraction x > 0.05. The higher center of mass energy s = 510 GeV allows to explore the gluon polarization as low as x ∼ 0.015. In this talk we will present the recent STAR inclusive jet and dijet ALL results at s = 510 GeV, and discuss the relevant new analysis techniques for the estimation of trigger bias and reconstruction uncertainty, the underlying event correction on the jet energy and its effect on jet ALL . Dijet results are shown for different topologies in regions of pseudo-rapidity, effectively scanning the x-dependence of the gluon polarization.

STAR Heavy-ion results

2020 ◽  
pp. 2040007
Author(s):  
David Tlusty
Keyword(s):  
Phase Diagram ◽  
Nuclear Physics ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collider ◽  
Qcd Phase Diagram ◽  
Ion Collisions ◽  
Dense Nuclear Matter ◽  
Star Experiment ◽  
Future Plans

The exploration of the Quantum Chromodynamics (QCD) phase diagram has been one of the main drivers of contemporary nuclear physics. Heavy-ion collisions provide a powerful tool to explore phase structures of strongly interacting hot and dense nuclear matter called Quark–Gluon Plasma (QGP). The Relativistic Heavy Ion Collider (RHIC) is uniquely suited to map the QCD phase diagram by varying the energy of collisions, as well as nuclei species. These proceedings discuss the most recent results from the STAR experiment at RHIC and future plans.

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