scholarly journals HADRON SPECTRA IN p+p COLLISIONS AT RHIC AND LHC ENERGIES

2013 ◽  
Vol 28 (16) ◽  
pp. 1350066 ◽  
Author(s):  
P. K. KHANDAI ◽  
P. SETT ◽  
P. SHUKLA ◽  
V. SINGH
Keyword(s):  
Hadron Collider ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collider ◽  
Systematic Analysis ◽  
Center Of Mass Energy ◽  
Hadron Spectra ◽  
200 Gev ◽  
Energy Formula ◽  
Two Parameters

We present the systematic analysis of transverse momentum (pT) spectra of identified hadrons in p+p collisions at Relativistic Heavy Ion Collider ([Formula: see text] and 200 GeV) and at Large Hadron Collider (LHC) energies ([Formula: see text], 2.76 and 7.0 TeV) using phenomenological fit functions. We review various forms of Hagedorn and Tsallis distributions and show their equivalence. We use Tsallis distribution which successfully describes the spectra in p+p collisions using two parameters, Tsallis temperature T which governs the soft bulk spectra and power n which determines the initial production in partonic collisions. We obtain these parameters for pions, kaons and protons as a function of center-of-mass energy [Formula: see text]. It is found that the parameter T has a weak but decreasing trend with increasing [Formula: see text]. The parameter n decreases with increasing [Formula: see text] which shows that production of hadrons at higher energies are increasingly dominated by point like qq scatterings. Another important observation is with increasing [Formula: see text], the separation between the powers for protons and pions narrows down hinting that the baryons and mesons are governed by same production process as one moves to the highest LHC energy.

HYDJET SIMULATIONS OF ELLIPTIC FLOW IN HEAVY ION COLLISIONS AT THE LHC

2007 ◽  
Vol 16 (07n08) ◽  
pp. 1917-1922
Author(s):  
D. KROFCHECK ◽  
R. MAK ◽  
P. ALLFREY
Keyword(s):  
Hadron Collider ◽  
Center Of Mass ◽  
Elliptic Flow ◽  
Heavy Ion ◽  
Event Generator ◽  
Simulation Tool ◽  
Mass Energy ◽  
Relativistic Heavy Ion Collider ◽  
Center Of Mass Energy ◽  
Ion Collisions

At the Relativistic Heavy Ion Collider (RHIC) elliptic flow signals (v2) appear to be stronger than those measured at lower center-of-mass energies. With the beginning of heavy ion beams at the Large Hadron Collider (LHC) it is important to have a reliable tool for simulating v2 at the LHC Pb – Pb center-of-mass energy of 5.5 A TeV. In this work we used the heavy ion simulation tool HYDJET to study elliptic flow at the event generator level. The generator level elliptic flow v2 for Pb – Pb collisions was two-particle and four-particle cumulants.

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.

Recent Mid-Rapidity ALLπ0 Measurements in Longitudinally Polarized Proton-Proton Collision at s = 510 GeV with PHENIX Experiment

2016 ◽  
Vol 40 ◽  
pp. 1660022
Author(s):  
Inseok Yoon
Keyword(s):  
Center Of Mass ◽  
Heavy Ion ◽  
Proton Collision ◽  
Relativistic Heavy Ion Collider ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Helicity Distribution ◽  
Statistical Precision ◽  
Polarized Proton ◽  
Energy Formula

It is one of the important purposes of relativistic heavy ion collider (RHIC) longitudinally polarized proton program to constrain the gluon helicity distribution ([Formula: see text]) to the proton by measuring the double helicity asymmetries ([Formula: see text]) via various probes such as [Formula: see text] ([Formula: see text]). The measurement at center of mass energy, [Formula: see text] GeV has been successfully finished and published. To explore lower x region, where dominant uncertainty remains, new measurements were carried out at an increased [Formula: see text] GeV. At this increased energy central [Formula: see text] measurements can reach a lower x range of [Formula: see text], while the previous can reach x range, [Formula: see text]. Also the statistical precision at the same transverse momentum ([Formula: see text]) is substantially improved due to accumulating about 10 times as much luminosity. Preliminary results of [Formula: see text] are presented. Larger asymmetry is observed at [Formula: see text] GeV than at [Formula: see text] GeV at the same [Formula: see text] which is expected due to evolution.

scholarly journals Particle production at RHIC and LHC energies

2015 ◽  
Vol 30 (22) ◽  
pp. 1550131 ◽  
Author(s):  
A. Tawfik ◽  
E. Gamal ◽  
A. G. Shalaby
Keyword(s):  
Particle Production ◽  
Hadron Collider ◽  
Center Of Mass ◽  
System Size ◽  
Alice Experiment ◽  
Center Of Mass Energy ◽  
Particle Ratios ◽  
Strangeness Enhancement ◽  
Homogeneous Particle ◽  
Energy Formula

The production of pion, kaon and proton was measured in Pb–Pb collisions at nucleus–nucleus center-of-mass energy [Formula: see text] by the ALICE experiment at Large Hadron Collider (LHC). The particle ratios of these species compared to the RHIC measurements are confronted to the hadron resonance gas (HRG) model and to simulations based on the event generators PYTHIA 6.4.21 and HIJING 1.36. It is found that the homogeneous particle–antiparticle ratios (same species) are fully reproducible by means of HRG and partly by PYTHIA 6.4.21 and HIJING 1.36. The mixed kaon–pion and proton–pion ratios measured at RHIC and LHC energies seem to be reproducible by the HRG model. On the other hand, the strange abundances are underestimated in both event generators. This might be originated to strangeness suppression in the event generators and/or possible strangeness enhancement in the experimental data. It is apparent that the values of kaon–pion ratios are not sensitive to the huge increase of [Formula: see text] from 200 (RHIC) to 2760 GeV (LHC). We conclude that the ratios of produced particle at LHC seem not depending on the system size.

scholarly journals A Review onϕMeson Production in Heavy-Ion Collision

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Md. Nasim ◽  
Vipul Bairathi ◽  
Mukesh Kumar Sharma ◽  
Bedangadas Mohanty ◽  
Anju Bhasin
Keyword(s):  
Hadron Collider ◽  
Center Of Mass ◽  
Meson Production ◽  
Dense Matter ◽  
Heavy Ion ◽  
Experimental Program ◽  
Proton Synchrotron ◽  
Relativistic Heavy Ion Collider ◽  
Super Proton Synchrotron ◽  
Strangeness Enhancement

The main aim of the relativistic heavy-ion experiment is to create extremely hot and dense matter and study the QCD phase structure. With this motivation, experimental program started in the early 1990s at the Brookhaven Alternating Gradient Synchrotron (AGS) and the CERN Super Proton Synchrotron (SPS) followed by Relativistic Heavy Ion Collider (RHIC) at Brookhaven and recently at Large Hadron Collider (LHC) at CERN. These experiments allowed us to study the QCD matter from center-of-mass energies (sNN) 4.75 GeV to 2.76 TeV. Theϕmeson, due to its unique properties, is considered as a good probe to study the QCD matter created in relativistic collisions. In this paper we present a review on the measurements ofϕmeson production in heavy-ion experiments. Mainly, we discuss the energy dependence ofϕmeson invariant yield and the production mechanism, strangeness enhancement, parton energy loss, and partonic collectivity in nucleus-nucleus collisions. Effect of later stage hadronic rescattering on elliptic flow (v2) of proton is also discussed relative to corresponding effect onϕmesonv2.

scholarly journals Hadron Spectra Parameters within the Non-Extensive Approach

Universe ◽  
2019 ◽  
Vol 5 (5) ◽  
pp. 122 ◽  
Author(s):  
Keming Shen ◽  
Gergely Gábor Barnaföldi ◽  
Tamás Sándor Biró
Keyword(s):  
High Energy Physics ◽  
Center Of Mass ◽  
Heavy Ion ◽  
High Energy ◽  
Proton Proton ◽  
Center Of Mass Energy ◽  
Ion Collisions ◽  
Hadron Spectra ◽  
Hadron Mass ◽  
Energy Scaling

We investigate how the non-extensive approach works in high-energy physics. Transverse momentum ( p T ) spectra of several hadrons are fitted by various non-extensive momentum distributions and by the Boltzmann–Gibbs statistics. It is shown that some non-extensive distributions can be transferred one into another. We find explicit hadron mass and center-of-mass energy scaling both in the temperature and in the non-extensive parameter, q, in proton–proton and heavy-ion collisions. We find that the temperature depends linearly, but the Tsallis q follows a logarithmic dependence on the collision energy in proton–proton collisions. In the nucleus–nucleus collisions, on the other hand, T and q correlate linearly, as was predicted in our previous work.

scholarly journals Comparing Multicomponent Erlang Distribution and Lévy Distribution of Particle Transverse Momentums

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Hua-Rong Wei ◽  
Ya-Hui Chen ◽  
Li-Na Gao ◽  
Fu-Hu Liu
Keyword(s):  
Hadron Collider ◽  
Center Of Mass ◽  
Heavy Ion ◽  
Erlang Distribution ◽  
Relativistic Heavy Ion Collider ◽  
Final State ◽  
Heavy Particles ◽  
Proton Proton ◽  
Lévy Distribution ◽  
Levy Distribution

The transverse momentum spectrums of final-state products produced in nucleus-nucleus and proton-proton collisions at different center-of-mass energies are analyzed by using a multicomponent Erlang distribution and the Lévy distribution. The results calculated by the two models are found in most cases to be in agreement with experimental data from the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). The multicomponent Erlang distribution that resulted from a multisource thermal model seems to give a better description as compared with the Lévy distribution. The temperature parameters of interacting system corresponding to different types of final-state products are obtained. Light particles correspond to a low temperature emission, and heavy particles correspond to a high temperature emission. Extracted temperature from central collisions is higher than that from peripheral collisions.

scholarly journals Future Circular Colliders

2019 ◽  
Vol 69 (1) ◽  
pp. 389-415 ◽  
Author(s):  
M. Benedikt ◽  
A. Blondel ◽  
P. Janot ◽  
M. Klein ◽  
M. Mangano ◽  
...  
Keyword(s):  
Particle Physics ◽  
Hadron Collider ◽  
Center Of Mass ◽  
Heavy Ion ◽  
New Physics ◽  
Proton Proton ◽  
Proton Collisions ◽  
Center Of Mass Energy ◽  
Physics Program ◽  
Electron Positron

After 10 years of physics at the Large Hadron Collider (LHC), the particle physics landscape has greatly evolved. Today, a staged Future Circular Collider (FCC), consisting of a luminosity-frontier highest-energy electron–positron collider (FCC-ee) followed by an energy-frontier hadron collider (FCC-hh), promises the most far-reaching physics program for the post-LHC era. FCC-ee will be a precision instrument used to study the Z, W, Higgs, and top particles, and will offer unprecedented sensitivity to signs of new physics. Most of the FCC-ee infrastructure could be reused for FCC-hh, which will provide proton–proton collisions at a center-of-mass energy of 100 TeV and could directly produce new particles with masses of up to several tens of TeV. This collider will also measure the Higgs self-coupling and explore the dynamics of electroweak symmetry breaking. Thermal dark matter candidates will be either discovered or conclusively ruled out by FCC-hh. Heavy-ion and electron–proton collisions (FCC-eh) will further contribute to the breadth of the overall FCC program. The integrated FCC infrastructure will serve the particle physics community through the end of the twenty-first century. This review combines key contents from the first three volumes of the FCC Conceptual Design Report.

scholarly journals Highlights from BNL-RHIC 2011–2013

2014 ◽  
Vol 29 (13) ◽  
pp. 1430017 ◽  
Author(s):  
M. J. Tannenbaum
Keyword(s):  
National Laboratory ◽  
Hadron Collider ◽  
Center Of Mass ◽  
50Th Anniversary ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Nucleon Nucleon ◽  
Brookhaven National Laboratory ◽  
Relativistic Heavy Ion Collider ◽  
Qcd Critical Point

Highlights from Brookhaven National Laboratory (BNL) and experiments at the BNL Relativistic Heavy Ion Collider (RHIC) are presented for the years 2011–2013. This review is a combination of lectures which discussed the latest results each year at a three year celebration of the 50th anniversary of the International School of Subnuclear Physics in Erice, Sicily, Italy. Since the first collisions in the year 2000, RHIC has provided nucleus–nucleus and polarized proton–proton collisions over a range of nucleon–nucleon center-of-mass energies [Formula: see text] from 7.7 GeV to 510 GeV with nuclei from deuterium to uranium, most often gold. The objective was the discovery of the Quark Gluon Plasma, which was achieved, and the measurement of its properties, which were much different than expected, namely a "perfect fluid" of quarks and gluons with their color charges exposed rather than a gas. Topics including quenching of light and heavy quarks at large transverse momentum, thermal photons, search for a QCD critical point as well as measurements of collective flow, two-particle correlations and J/Ψ suppression are presented. During this period, results from the first and subsequent heavy ion measurements at the Large Hadron Collider (LHC) at CERN became available. These confirmed and extended the RHIC discoveries and have led to ideas for new and improved measurements.

FIRST RESULTS FROM THE PHOBOS EXPERIMENT AT THE RHIC COLLIDER

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1265-1267
Author(s):  
◽  
JUDITH KATZY ◽  
B. B. Back ◽  
M. D. Baker ◽  
D. S. Barton ◽  
...  
Keyword(s):  
Center Of Mass ◽  
Charged Particles ◽  
Heavy Ion ◽  
Mass Energy ◽  
Relativistic Heavy Ion Collider ◽  
Center Of Mass Energy ◽  
Central Collisions ◽  
First Results ◽  
Pseudorapidity Density

PHOBOS is one of the four experiments at the Relativistic Heavy Ion Collider that started colliding gold nuclei at a center of mass energy of √sNN = 56 and 130 GeV per pair of colliding nucleons in June 2000. The pseudorapidity density of primary charged particles in central collisions has been measured near mid-rapidity.

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