ANTI-PROTON TO PROTON RATIOS FROM Au + Au COLLISIONS AT $\sqrt{s_{NN}}=200~{\rm GeV}$ BY RQMD

2003 ◽  
Vol 18 (16) ◽  
pp. 1107-1112
Author(s):  
YUNHUA CHENG ◽  
FENG LIU
Keyword(s):  
Transverse Momentum ◽  
Center Of Mass ◽  
Experimental Results ◽  
Mass Energy ◽  
Center Of Mass Energy

Events of Au + Au collisions from AGS to RHIC energies by RQMD (v2.4) generator are produced. [Formula: see text] ratios as functions of rapidity, transverse momentum and centrality at [Formula: see text] are studied. The dependence on the center of mass energy of [Formula: see text] ratios is presented, compared with the experimental results. It is shown that [Formula: see text] ratio from rescattering RQMD is lower than those of the experiments at RHIC energies. We argue that hadronic rescattering at RHIC energies is suppressed compared to AGS, SPS energies.

scholarly journals Transverse Momentum and Pseudorapidity Distributions of Charged Particles and Spatial Shapes of Interacting Events in Pb-Pb Collisions at 2.76 TeV

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Fu-Hu Liu ◽  
Ya-Qin Gao ◽  
Tian Tian ◽  
Bao-Chun Li
Keyword(s):  
Transverse Momentum ◽  
Thermal Model ◽  
Center Of Mass ◽  
Charged Particles ◽  
Nucleon Pair ◽  
Mass Energy ◽  
Center Of Mass Energy ◽  
Rapidity Distributions ◽  
Pseudorapidity Distributions ◽  
Parameter Values

The transverse momentum and pseudorapidity distributions of charged particles produced in Pb-Pb collisions with different centrality intervals at center-of-mass energy per nucleon pairsNN=2.76 TeV have been analyzed by using the improved multisource thermal model in which the whole interacting system and then the sources are described by the Tsallis statistics. The modelling results are in agreement with experimental data of the ALICE Collaboration. The rapidity distributions of charged particles are obtained according to the extracted parameter values. The shapes of interacting events (the dispersion plots of charged particles) are given in the momentum, rapidity, velocity, and coordinate spaces. Meanwhile, the event shapes in different spaces consisted by different transverse quantities and longitudinal quantities are presented.

scholarly journals Extracting the QCD ΛMS¯ parameter in Drell–Yan process using Collins–Soper–Sterman approach

2017 ◽  
Vol 32 (10) ◽  
pp. 1750040 ◽  
Author(s):  
R. Taghavi ◽  
A. Mirjalili
Keyword(s):  
Experimental Data ◽  
Transverse Momentum ◽  
Cross Section ◽  
Center Of Mass ◽  
Distribution Functions ◽  
Mass Energy ◽  
Transverse Momentum Dependent ◽  
Center Of Mass Energy ◽  
Dimensional Transmutation ◽  
High Center

In this work, we directly fit the QCD dimensional transmutation parameter, [Formula: see text], to experimental data of Drell–Yan (DY) observables. For this purpose, we first obtain the evolution of transverse momentum dependent parton distribution functions (TMDPDFs) up to the next-to-next-to-leading logarithm (NNLL) approximation based on Collins–Soper–Sterman (CSS) formalism. As is expecting the TMDPDFs are appearing at larger values of transverse momentum by increasing the energy scales and also the order of approximation. Then we calculate the cross-section related to the TMDPDFs in the DY process. As a consequence of global fitting to the five sets of experimental data at different low center-of-mass energies and one set at high center-of-mass energy, using CETQ06 parametrizations as our boundary condition, we obtain [Formula: see text] MeV corresponding to the renormalized coupling constant [Formula: see text] which is within the acceptable range for this quantity. The goodness of [Formula: see text] shows the results for DY cross-section are in good agreement with different experimental sets, containing E288, E605 and R209 at low center-of-mass energies and [Formula: see text], CDF data at high center-of-mass energy. The repeated calculations, using HERAPDFs parametrizations is yielding us numerical values for fitted parameters very close to what we obtain using CETQ06 PDFs set. This indicates that the obtained results have enough stability by variations in the boundary conditions.

scholarly journals Virtual corrections to gg → ZH via a transverse momentum expansion

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lina Alasfar ◽  
Giuseppe Degrassi ◽  
Pier Paolo Giardino ◽  
Ramona Gröber ◽  
Marco Vitti
Keyword(s):  
Transverse Momentum ◽  
Cross Section ◽  
Center Of Mass ◽  
Gluon Fusion ◽  
Partonic Cross Section ◽  
Mass Energy ◽  
Final State ◽  
Center Of Mass Energy ◽  
Total Hadronic Cross Section ◽  
Better Than

Abstract We compute the next-to-leading virtual QCD corrections to the partonic cross section of the production of a Higgs boson in association with a Z boson in gluon fusion. The calculation is based on the recently introduced method of evaluating the amplitude via an expansion in terms of a small transverse momentum. We generalize the method to the case of different masses in the final state and of a process not symmetric in the forward-backward direction exchange. Our analytic approach gives a very good approximation (better than percent) of the partonic cross section in the center of mass energy region up to ∼ 750 GeV, where at the LHC ∼ 98% of the total hadronic cross section is concentrated.

scholarly journals Elliptic Flow of Identified Particles in Pb–Pb Collisions at sNN=5.02 TeV

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Er-Qin Wang ◽  
Yin-Qun Ma ◽  
Li-Na Gao ◽  
San-Hong Fan
Keyword(s):  
Transverse Momentum ◽  
Geometric Structure ◽  
Thermal Model ◽  
Center Of Mass ◽  
Elliptic Flow ◽  
Mass Energy ◽  
Final State ◽  
Center Of Mass Energy ◽  
Dynamic Factors ◽  
Diffusion Effects

In this paper, by using a Tsallis-Pareto-type function and the multisource thermal model, the elliptic flow coefficients of particles π±, K±, p+p¯, Λ+Λ¯, and KS0 produced in Pb–Pb collisions at the center-of-mass energy of sNN=5.02TeV are investigated. In the process of collisional evolution, because of geometric structure, pressure gradient, and thermal diffusion effects, deformation and translation occurred in the isotropic emission source, leading to anisotropy in the azimuth distribution of the final-state particles. Based on these dynamic factors, the dependence of elliptic flow on transverse momentum is described as well.

scholarly journals Measurement of two- and four-particle correlations in p-Pb and Pb-Pb collisions at CMS

2014 ◽  
Vol 12 (2) ◽  
pp. 167-177
Author(s):  
Jovan Milosevic
Keyword(s):  
Center Of Mass ◽  
Nucleon Nucleon ◽  
Experimental Results ◽  
Color Glass ◽  
Color Glass Condensate ◽  
Two Dimensional ◽  
Mass Energy ◽  
Particle Correlation ◽  
Fourier Harmonic ◽  
Center Of Mass Energy

Results of two- and four-particle angular two-dimensional correlations in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV, collected with the CMS detector, are presented. In high-multiplicity pPb events a ridge-like structure at the near-side emerges in two-particle ??-?? correlation. It is compared to the ridge found in 2.76 TeV PbPb collisions. In both systems, the ridge yield rises, reaches a maximum at pT ? 1-3 GeV/c and then decreases at higher pt, and increases monotonically with multiplicity. The 2-nd order Fourier harmonic has qualitatively similar pT dependence, but with a moderate multiplicity dependence in both systems. The multiplicity dependence of the 3-rd Fourier harmonic is rather similar for pPb and PbPb collisions. Color glass condensate and hydrodynamic predictions are compared to the experimental results.

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