QGSJETII-04 Models Research Articles

Muons in showers with energy $\boldsymbol{E_{0} \geq}$ 5 EeV and QGSjetII-04 and EPOS LHC models of hadronic interactions. Is there a muon deficit in the models?

The paper presents data on the muon component with a threshold\varepsilon_{thr} \geqεthr≥ 1 GeV. Air showers were registered at the Yakutsk array during almost 50 years of continuous air shower observations. The characteristics of muons are compared with calculations of QGSjetII-04 and EPOS LHC models for a proton and an iron nucleus. There is a muon deficit in the models, at energies greater than 5 EeV. To make an agreement between experimental data and simulations on muons, further tuning of the models is required.

Study of transverse momentum and nuclear modification factors distribution of charged particles produced in pp and Pb–Pb collisions at s NN = 2.76TeV and 5.02TeV

We have studied transverse momentum distributions of charged particles produced in pp and Pb–Pb collisions at [Formula: see text] TeV and 5.02 TeV in the pseudorapidity interval [Formula: see text] and transverse momentum range [Formula: see text][Formula: see text]GeV/[Formula: see text]. We simulated data using EPOS-LHC, EPOS-1.99 and QGSJETII-04 models. The simulation data is compared with the ALICE experimental data values at [Formula: see text] TeV and 5.02 TeV for pp and most central Pb–Pb collisions. It has been observed that, EPOS-LHC and QGSJETII-04 models explain the experimental results for pp collision at [Formula: see text] TeV and 5.02 TeV. The behavior of nuclear modification factors has been studied. The simulation codes of all three models EPOS-LHC, EPOS-1.99 and QGSJETII-04 overestimate the experimental results at low transverse momentum interval: [Formula: see text] GeV/[Formula: see text], for Pb–Pb collisions at [Formula: see text] TeV and 5.02 TeV. However, only EPOS-LHC model can explain the experimental data at high transverse momentum in the range: [Formula: see text] GeV/[Formula: see text]. EPOS-1.99 and QGSJETII-04 underestimate in the region of Cronin effect and cannot give satisfactory estimates for the [Formula: see text] values for which [Formula: see text] demonstrates stronger suppression because of the collective parton effect. It can be inferred that these effects are not taken into account in EPOS-1.99 and QGSJETII-04 models. These models, however, satisfactorily explain the ALICE experimental data in the ranges of [Formula: see text] for which nuclear modification factor [Formula: see text] shows rising trend.

Mass composition of cosmic rays determined by the muon fraction with ϵthr≥1 GeV in air showers with energy greater than 5 EeV

The ratio of the number of muons with a threshold of 1 GeV and charged particles at a distance of 600 m from the axis is analyzed. Air showers with energies above 5 EeV and zenith angles with less than 60 degrees are considered. Comparison of experimental data with calculations by the QGSJETII-04 model for various primary nuclei, including a gamma ray, showed that the mass composition of cosmic rays up to energies of $\sim$ 10 EeV mainly consists of protons and helium nuclei, with a small number of heavy nuclei. Data include air showers with a very low muon content, which are assumed to be produced by primary gamma rays.

Study of the Production of Strange Particles in Proton–Proton Collisions at √s = 0.9 TeV

The differential yield of strange mesons $$ (K_{s}^{0} ,\phi ) $$ and singly and doubly strange baryons (Λ, $$ \bar{\varLambda } $$ and Ξ) in pp collision at 0.9 TeV in the transverse momentum (pT) ranging from 0.1 to 3.5 GeV/c and in the rapidity region of |y| <0.75 is reported. The spectra obtained by Monte Carlo simulations with event generators: EPOS 1.99, EPOS-LHC, HIJING 1.38, QGSJETII-04 and Sibyll2.3c, are compared with the ALICE measurements. For $$ K_{s}^{0} $$, EPOS-LHC, Sibyll2.3c and QGSJETII-04 models’ predictions are closer to the experimental data at low pT. For Λ and $$ \bar{\varLambda } $$, EPOS 1.99 and QGSJETII-04 predict in some of the pT regions, while only EPOS 1.99 model predicts well the Ξ spectra. QGSJETII-04 and Sibyll2.3c predict well the distribution of $$ \phi $$ mesons at high pT. For Λ/$$ K_{s}^{0} $$, only QGSJETII-04 predicts the ratio very well. Although the models are qualitatively compatible with the data, none of them predict all the distributions over the entire pT range.

Estimation of The Cosmic Ray Mass Composition at Energy Above 1017 eV According to Scintillation Detectors of the Yakutsk Array

The lateral distribution of cascade particles was studied in extensive air showers initiated by cosmic rays with energies above 1017 eV. The study is based on experimental data of ground-based and ground-shielded (with ∼1-GeV energy threshold) scintillation detectors of the Yakutsk EAS array collected during the continuous observational period from 1977 to 2017. Particle density measured in experiment is compared to the results of simulations performed with the use of several ultra-high energy hadron interaction models. The best agreement between theory and experiment was obtained for qgsjet01 and qgsjet ii-04 models. Interpretation of our data has indicated that within the energy range (1–30) × 1017 eV the cosmic ray mass composition changes from nuclei of intermediate group towards protons.

Composition of Cosmic Rays with Energy More than 0.1 EeV by Long-Term Optical Observations of Cherenkov Emission at Yakutsk EAS Array

The paper presents results on longitudinal development of air showers with ultra-high energies and mass composition of cosmic rays 〈ln A〉. The data is obtained from observations of Cherenkov emission at the Yakutsk array in 1974–2014. Cascade curves of individual showers reconstructed by lateral distribution of Cherenkov light and depth of maximum Xmax are analyzed in the energy region 1016–6 × 1019 eV. Composition of cosmic rays is determined by interpolation of hadronic interaction QGSJETII-04 model.

Distribution of strange particles transverse momentum and rapidity in high energy proton–proton collisions at s = 0.9 TeV at LHC

In this paper, we have studied the spectra of strange particles in pp collision at [Formula: see text] = 0.9 TeV by using different simulation models, EPOS-1.99, SIBYLL-2.3c, QGSJETII-04 and EPOS-LHC. The transverse momentum and rapidity distribution in the [Formula: see text] range of [Formula: see text] GeV/c and [Formula: see text] GeV/c, respectively, are investigated for the strange particles, [Formula: see text], [Formula: see text], [Formula: see text]. Similarly, a comparative study is done for the ratio of [Formula: see text] and [Formula: see text] as a function of transverse momentum and rapidity. The validity of simulation models is tested by comparing simulation results to the CMS experimental data at [Formula: see text] = 0.9 TeV. For [Formula: see text] distributions, the EPOS-LHC model in the [Formula: see text] range [Formula: see text] GeV/c, [Formula: see text] GeV/c and in [Formula: see text] GeV/c while EPOS-1.99 model in the [Formula: see text] range [Formula: see text] GeV/c and QGSJETII-04 model in the [Formula: see text] range [Formula: see text] GeV/c as well as, [Formula: see text] GeV/c explain the experimental data well. For the, [Formula: see text] and [Formula: see text] versus transverse momentum distributions, EPOS-LHC model in the [Formula: see text] range of, [Formula: see text] GeV/c and [Formula: see text] GeV/c, EPOS-1.99 model in the [Formula: see text] range, [Formula: see text] GeV/c, SIBYLL-2.3c model in the [Formula: see text] range, [Formula: see text] GeV/c and QGSJETII-04 model in the [Formula: see text] range [Formula: see text] GeV/c explain the experimental data very well. Similarly, for [Formula: see text] and [Formula: see text] versus rapidity distribution QGSJETII-04 predictions in the rapidity region, [Formula: see text], [Formula: see text], and [Formula: see text], while EPOS-LHC model in the region, [Formula: see text], very well explained the experimental data. Although good comparison of the models predictions with the experimental data is observed, none of them completely describe the experimental data the spectra of strange particles over the entire [Formula: see text] and [Formula: see text] range.

New Estimates of the Energy of Inclined Showers, According to the EPOS LHC and QGSJETII-04 Models

It is proposed that the energy of inclined extensive air showers be estimated using signals from the surface scintillation detectors of the Yakutsk array, located at a distance of 600 m from the shower axis and the zenith angle of shower arrival. Estimates of the energy of inclined showers are calculated using new formulas obtained from simulations using different models of hadron interaction. These models of hadron interaction are validated by comparing calculated and experimental spectra of atmospheric muons. It is found that the muon spectrum calculated with the EPOS LHC and QGSJETII-04 models differs little from the experimental spectrum. It is shown for the first time that the energy spectrum of primary cosmic radiation is in good agreement with the literature data.

Mass composition of cosmic rays above 0.1 EeV by the Yakutsk array data

The paper presents the results of the longitudinal development of extensive air showers (Xmax) of ultra-high energies and mass composition of cosmic rays. The measurements of Xmax are based on data from observations of the Cherenkov radiation at the Yakutsk array for the period 1974–2014. The cascade curves of individual showers and the depth of maximum Xmax were reconstructed over the energy range 1016–5.7 · 1019 eV. It is shown that the displacement rate of the parameter dXmax/dE in the atmosphere is nonlinear and depends on the energy. Such a feature indicates a change in mass composition, which is confirmed by fluctuations of Xmax in this energy region. The composition of cosmic rays was determined by interpolation using the QGSJetII-04 model.

PT spectra of charged hadrons in proton–proton collisions at s = 200 GeV

The transverse momentum spectra of [Formula: see text] mesons, protons and antiprotons produced in proton–proton collisions at 200 GeV with hadron production models are reported. Two tunes of EPOS (EPOS1.99 and EPOS-LHC), three tunes of QGSJET (QGSJETI, QGSJETII-03, QGSJETII-04), DPMJET and HIJING models are used to obtain the spectra. The results are compared with the measurements of STAR collaboration obtained at mid-rapidity of [Formula: see text] in [Formula: see text] range of [Formula: see text]. All models reproduce the ratios [Formula: see text] and [Formula: see text] at low [Formula: see text] but could not predict well at high [Formula: see text]. In addition, EPOS tunes and QGSJET tunes predict well the spectra of [Formula: see text] meson and the ratios [Formula: see text] and [Formula: see text] at low [Formula: see text]. The HIJING and the QGSJET (tune I only) could reproduce all the spectra and all the ratios at a satisfactory level of precision and were found good among the models considered in the current study at RHIC energy.

Study of Hadrons Produced in Proton—Carbon Interactions at 120 GeV/c Using Hadron-Production Models

Double differential yield of π±, K±, protons, and antiprotons as a function of laboratory momentum is presented using hadron production models. This study is done in several polar angle intervals from 0 < θ < 420 mrad for π± mesons and 0 < θ < 360 mrad for K± mesons, protons, and antiprotons. The study is carried out for p + C interactions at 120 GeV/c. For simulation, three hadron-production models: EPOS-LHC, EPOS 1.99, and QGSJETII-04 are used. Since no experimental data at 120 GeV/c is available yet, therefore, the models’ predictions are compared with the measurements of NA61/SHINE experiments at 31 GeV/c. It is found that the QGSJETII-04 model gives high peak value, for π± mesons, in the polar angle interval of 20–40 mrad, while in the range of 40–240 mrad, EPOS-LHC shows higher yield than EPOS 1.99 and QGSJETII-04 models, whereas all show higher yield than the experimental data. For π± mesons, in all angular intervals, at high momentum values, all the three models are consistent and surprisingly give the same yield as that of the experimental data. For K± mesons, QGSJETII-04 shows higher peak values at all polar angles ranging from 0 to 360 mrad as compared to that of EPOS 1.99 and EPOS-LHC models, whereas all models give higher yield at low angular intervals than the experimental data and the same yield at high angular intervals. The models demonstrate similar yields for protons at all angles but underestimate the experimental data at low angular intervals and provide the same yield at high angular intervals. The QGSJETII-04 model presents higher yields of antiprotons in comparison to the EPOS 1.99 and EPOS-LHC models, for almost all angular intervals. Generally, at higher angular range, i.e., from 240 to 420 mrad, particularly at high momentum, all the three models show similar results.

Mass Composition of Cosmic Rays with Energies above 1017 eV According to the Data from the Muon Detectors of the Yakutsk EAS Array

The lateral distribution of muons in extensive air showers with energies above 1017 eV detected by underground scintillation detectors with a threshold of 1.0 GeV at the Yakutsk array in 1986–2016 has been analyzed. The experimental data on the muon flux density at a distance of 300 m from the shower axis have been compared to the calculations within various models of hadron interactions at ultrahigh energies. The experimental data are in the best agreement with the QGSJet01 and QGSJet II-04 models. The mass composition of cosmic rays in the energy range of (1–30) × 1017 eV changes from middle nuclei to a purely proton composition.

Production of light flavored charged hadron in pp collisions at 900 GeV with hadron production models

Differential yields of light flavored charged hadrons in [Formula: see text] collision at 0.9 TeV in the transverse momentum [Formula: see text] ranging from 0.1–2.5 GeV/c with pseudorapidity [Formula: see text] are presented here. The spectra obtained by Monte Carlo simulations with event generators — EPOS 1.99, EPOS-LHC, QGSJETII-04 and Sibyll2.3c — are compared with the ALICE measurements. For [Formula: see text] mesons, EPOS1.99, EPOS-LHC and QGSJETII-04 described the ALICE measurement very well almost in the entire [Formula: see text] range except QGSJETII-04 which underpredicts with [Formula: see text] below 0.4 GeV/c. The Sibyll2.3c model slightly overpredicts for [Formula: see text] GeV/c and underpredicts afterwards. For [Formula: see text] mesons, all models describe the experimental data qualitatively, except at high [Formula: see text], where the models slightly underpredict. The EPOS-LHC and QGSJETII-04 models, at low [Formula: see text], describe the distribution of the experimental measurements very well in both cases of protons and anti-protons, whereas the former underpredicts and the latter overpredicts at higher [Formula: see text]. The EPOS1.99 overpredicts at low [Formula: see text] below 1 GeV/c, whereas it reproduces the results well above it. Sibyll2.3c overpredicts the distribution over the entire range of [Formula: see text]. Models described the average transverse momentum [Formula: see text] of these hadron species as a function of their mass, showing small rise in the average [Formula: see text] with the mass of the particles. The same has been observed by the STAR collaboration with measurements in [Formula: see text] reactions at [Formula: see text] = 200 GeV and also in [Formula: see text] collisions at [Formula: see text] = 900 GeV.

Distributions of the Transverse Momentum and Pseudorapidity of Charged Particles in pp Collisions at 0.9 TeV

We have studied the charged particles spectra for the pseudorapidity region of ∣η∣ < 2.5, the multiplicity of charged particles, its dependence on pT as well as on η and the relation between average pT and charged particles multiplicity in pp collisions at √s = 0.9 TeV. For simulations, we have used the EPOS-LHC, EPOS-1.99, QGSJETII-04, and SIBYLL-2.3c models and compared their predictions with the experimental data of ATLAS experiment. For the pT distribution, predictions of the Sibyll-2.3c are matching with the experimental data in a region of 0.5 GeV/c < pT < 0.8 GeV/c and EPOS-1.99 model results are near to the experimental data for 0.5 GeV/c < pT < 1.5 GeV/c. For the case of average pT, EPOS-LHC, and Sibyll-2.3c predictions are closer to the experimental data. For the pseudorapidity charged particle density distributions, QGSJETII-04 model predictions are better describing the experimental data.

Study of Pseudorapidity and Transverse-Momentum Distributions of Charged Particles in pp Interactions at √s = 13 TeV Using Hadron Production Models

Pseudorapidity (η) and Transverse momentum (pT) distributions of charged particles produced in proton-proton (pp) collisions at √s = 13 TeV are studied. Transverse momentum distributions of charged particles are considered in the Pseudorapidity region of |η| < 0.8 and in the transverse momentum range of 0 < pT < 20 GeV/c. EPOS1.99, EPOS-LHC and QGSJETII-04 models are used to perform simulations. In order to check the validity of simulations performed using these Monte-Carlo event generators, the results are compared to the measurements of ALICE experiment at the LHC CERN. For the pT distribution, the EPOS1.99 and QGSJET underpredict the experimental data while the EPOS-LHC model reproduced the distribution very well. EPOS-LHC model describes the experimental data very well as compared to the other two models for the ratio of pT spectra of charged particles at √s = 13 TeV to 7 TeV. EPOS-LHC also describes the pseudorapidity distribution very well while the EPOS 1.99 and QGSJETII-04 underpredict and overpredict the distribution respectively.

Study of transverse momentum distributions in p−Pb interactions at 0.9 TeV and 5.02 TeV

This work is aimed to investigate the transverse momentum ([Formula: see text]) distributions of primary charged particles produced in p[Formula: see text][Formula: see text]Pb collisions at [Formula: see text][Formula: see text]0.9 TeV and 5.02 TeV. In this perspective, we have considered the pseudorapidity [Formula: see text] regions of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] and the transverse momentum range of [Formula: see text]. In order to check the validity of simulation, we have compared the prediction of EPOS-1.99, EPOS-LHC and QGSJETII-04 models with the measurement of the [Formula: see text] distribution of ALICE experiment at [Formula: see text][Formula: see text]5.02 TeV for [Formula: see text], [Formula: see text], [Formula: see text], and with the CMS experiment for [Formula: see text]. We discovered that all the models overpredict the distribution of the experimental data for [Formula: see text][Formula: see text]5 GeV/c while presenting consistent result with each other at 0.9 TeV as well as 5.02 TeV. For [Formula: see text][Formula: see text]5 GeV/c, the models seem to be consistent with the experimental data where the EPOS-LHC describes both the ALICE and CMS data very well.

Spectra of strange hadrons and their role in neutrinos flux prediction

Hadron production measurements are important for the long baseline neutrino oscillation experiment as well as for the study of extensive air shower produced by cosmic rays. For precise measurements of the neutrinos flux prediction, and Λ need to be considered. To this aim, the study of and Λ in polar angle intervals of 0 to 300 mrad and 0 to 420 mrad, respectively, is carried out. Hadron production models, EPOS 1.99, EPOS-LHC and QGSJETII-04, are used to simulate the particles with proton-carbon interactions at 31 GeV/c. The models predictions are compared with the measurements of the NA61/SHINE experiment based on the analysis of data collected in 2009 with a carbon target. None of the models completely describe the experimental data over the entire range of momentum and angular intervals. EPOS 1.99 and EPOS-LHC give a good description of the data for both strange particles except at for Λ, where the models overestimate. The QGSJETII-04 model overestimates the yield of the strange hadrons around the peak of the distribution, primarily at low angular intervals. Generally, all models are in excellent agreement at high momentum values of the distributions.

π±, K±, protons and antiprotons production in proton–carbon interactions at 31 GeV/c using hadron production models

Projects proposed for the long baseline neutrino and cosmic rays’ experiments require high precision hadron production measurements, using proton beam on different targets, to achieve their physics goals. The predictions of neutrino beam depend on the modeling of protons interacting within the targets. Thus, different hadronic models are being used for this purpose with different precisions, which depend on the projectile protons energy and material of the target used. The comparison of different hadron production models predictions, in proton–carbon interactions at 31 GeV/c, is reported in this paper. Double differential yield of [Formula: see text], [Formula: see text] mesons, protons and antiprotons in several polar angle ranges is presented as a function of laboratory momentum. EPOS1.99, EPOS-LHC and QGSJETII-04 models are used to perform simulations. The results of the simulated data are compared with hadron production measurements in proton–carbon interactions at 31 GeV/c performed by the NA61/SHINE experiment at the SPS CERN [Eur. Phys. J. C 76, 84 (2016)]. None of the models completely describes all the distributions. In most of the cases, EPOS1.99 describes the experimental data very well. EPOS-LHC results are also similar in some cases, but QGSJETII-04 predictions failed to reproduce the experimental data.

Comparison of different hadron production models for the study of π±, K±, protons and antiprotons production in proton–carbon interactions at 90 GeV/c

In this research paper, comprehensive results on the double differential yield of [Formula: see text] and [Formula: see text] mesons, protons and antiprotons as a function of laboratory momentum in several polar angle ranges from 0–420 mrad for pions, 0–360 mrad for kaons, proton and antiproton are reported. EPOS 1.99, EPOS-LHC and QGSJETII-04 models are used to perform simulations. The predictions of these models at 90 GeV/c are plotted for comparison, which shows that QGSJETII-04 model gives overall higher yield for [Formula: see text] mesons in the polar angle interval of 0–40 mrad but for the [Formula: see text] the yield is higher only up to 20 mrad. For [Formula: see text] mesons after 40 mrad, EPOS-LHC predicts higher yield as compared to EPOS 1.99 and QGSJETII-04 while EPOS-LHC and EPOS 1.99 give similar behavior in these two intervals. However, for [Formula: see text] mesons EPOS-LHC and EPOS 1.99 give similar behavior in these two intervals. For of [Formula: see text] mesons, QGSJETII-04 model gives higher predictions in all cases from 0–300 mrad, while EPOS 1.99 and EPOS-LHC show similar distributions. In case of protons, all models give similar distribution but this is not true for antiproton. All models are in good agreement for p [Formula: see text] 20 GeV/c. EPOS 1.99 produce lower yield compared to the other two models from 60–360 mrad polar angle interval.

Comparison of hadron production models for π±, k±, protons and antiprotons production in proton–carbon interactions at 60 GeV/c

In this research paper, the comprehensive results on the double differential yield of [Formula: see text] and [Formula: see text] mesons, protons and antiprotons as a function of laboratory momentum are reported. These hadrons are produced in proton–carbon interaction at 60 GeV/c. EPOS 1.99, EPOS-LHC and QGSJETII-04 models are used to perform simulations. Comparing the predictions of these models show that QGSJETII-04 model predicts higher yields of all the hadrons in most of the cases at the peak of the distribution. In this interval, the EPOS 1.99 and EPOS-LHC produce similar results. In most of the cases at higher momentum of the hadrons, all the three models are in good agreement. For protons, all models are in good agreement. EPOS-LHC gives high yield of antiprotons at high momentum values as compared to the other two models. EPOS-LHC gives higher prediction at the peak value for [Formula: see text] mesons and protons at higher polar angle intervals of [Formula: see text] and [Formula: see text], respectively, and EPOS 1.99 gives higher prediction at the peak value for [Formula: see text] mesons for [Formula: see text]. The model predictions, except for antiprotons, are compared with the data obtained by the NA61/SHINE experiment at 31 GeV/c proton–carbon collision, which clearly shows that the behavior of the distributions in models are similar to the ones from the data but the yield in data is low because of lower beam energy.