Hadron production models\u2019 prediction for pT distribution of charged hadrons in pp interactions at 7 TeV

S Ullah,H Younis,M Ajaz,K H Khan,Y Ali,Z Wazir

doi:10.1038/s41598-019-48272-4

Abstract

The yield of transverse momentum (pT) spectra of integrated hadrons and their ratios produced in pp collisions at 7 TeV are reported using DPMJET-III, EPOS1.99, EPOS-LHC, HIJING1.383, QGSJETII-04, and Sibyll2.3c models. The models’ predictions are compared with the ALICE measurements obtained at mid rapidity and in the pT range from 0.3–6 GeV/c, 0.2–6 GeV/c, and 0.1–3 GeV/c for protons, kaons and pions respectively. Compared to the experimental data, the EPOS1.99 and EPOS-LHC models predict the yield of pion very well while reproducing yields of kaon and proton at low pT only. The DPMJET-III model predicts the yield of pions, kaons and protons only at intermediate value of pT. The HIJING and Sibyll models describe the integrated yield of pion well at high pT only. The QGSJETII model predicts the yield of kaon for almost the whole pT range. EPOS1.99 and Sibyll models reproduce excellent prediction of the K/π ratio over the entire range of pT whereas the EPOS-LHC, HIJING and DPMJET models underpredict with increasing order of discrepancy respectively. The EPOS1.99, EPOS-LHC, and Sibyll models predict the p/π ratio for low values of pT, but overpredict at high values, while the DPMJET-III and HIJING models underpredict over the entire range of pT. Although the models’ predictions are mostly consistent with the ALICE measurements but none of the models completely describe the entire distribution for the integrated yield of hadron and their ratios.

Highlights

The measurements of hadron production have an extended record in high energy nuclear and particle physics[1,2,3,4,5,6,7,8,9,10,11,12,13]
Solid red line is used to represent the prediction of DPMJET-III model, blue for EPOS1.99, green for EPOS-Large Hadron Collider (LHC), yellow for HIJING, purple for QGSJET while dash red line is used for Sibyll
Comparing to the experimental data, DPMJET-III model predicts the yield of pions, kaons and protons for 1.2 < pT < 1.7 GeV/c, 3.3 < pT < 5.2, and 2.1 < pT < 3.1 respectively within 10%, 15% and 15%

Summary

Introduction

The measurements of hadron production have an extended record in high energy nuclear and particle physics[1,2,3,4,5,6,7,8,9,10,11,12,13]. In order to test soft parton interactions and hadronization processes predicted by non-perturbative quantum chromodynamics, the transverse momentum (pT) spectra and absolute yields of hadrons are used by Monte Carlo (MC) event generators[14]. We get important information on multi-parton interactions and other final state effects from the dependence of the yield and pT distribution on the hardness in pp collisions. The identified hadron distributions in pp collisions provide an important reference to the findings of high-energy heavy-ion analysis, where the spectral shape and yield of hadron species are modified by the final state effect. The present analysis is focused on the study of pT spectra of the integrated yield of π (π+ + π−), K (K+ + K−), proton (proton + anti-proton) production, and the K/π and p/π ratios in proton-proton (pp) interactions at 7 TeV using DPMJET-III, HIJING1.383, EPOS, QGSJETII-04, and Sibyll2.3c models, and their comparison with the data from the ALICE experiment[11]. The analysis, in future, will be extended to heavy ion collision for the study of strongly interacting matter and to search for a signal on the onset of deconfinement

Methods

Results

Conclusion