Pseudorapidity dependence of the transverse momentum distribution of charged particles in pp collisions at 0.9, 2.36, and 7 TeV

Abstract

We study the transverse momentum spectra of charged particles from 0.1−2 GeV/c in bins of pseudorapidity η of width 0.2 ranging from 0 to 2.4 produced in pp collisions, at three different center of mass energies, namely s=0.9, 2.36, 7TeV. We used PYTHIA8.307 and QGSJETII-04 and compared the simulation results with experimental data under the same conditions. The PYTHIA8 model has an excellent description of the experimental data, particularly at the high pT region of the distribution, and the prediction is independent of the η ranges. Furthermore, the predictions are more or less the same at lower values of pT, but a more prominent bump is observed for 0.4≤pT≤0.8GeV/c with increasing the center-of-mass energy. The QGSJET model reproduces the data only in the intermediate region of the pT over all the η slices and underpredicts for low and high pT regions. With the increase in the center of mass energy, the model’s predictions got closer to the data, particularly at a high part of the pT distributions. Furthermore, the Blast wave model with Tsallis statistics is applied to the pT spectra of CMS data and PYTHIA8 and QGSJET models, and the kinetic freeze-out temperature, transverse flow velocity, and the entropy parameter q are extracted. The kinetic freeze-out temperature increases from lower pseudorapidity regions to higher pseudo-rapidity regions. Transverse flow velocity and the entropy parameter q have the opposite trend to kinetic freeze-out temperature. All these parameters are also more significant at 7TeV and have the lowest values at 0.9TeV, which shows the dependence of these parameters on the collision energy.

Keywords

• Pseudorapidity bins
• Transverse momentum spectra
• Kinetic freeze-out temperature
• Transverse flow velocity