Quark-Gluon String Model and EAS Simulation Problems at Ultra-High Energies
01 Feb 1997-Vol. 52, Iss: 3, pp 17-28
TL;DR: The reliability of model calculations is of considerable significance because at energies above those attained by accelerators only model predictions enable us to extract primary cosmic ray characteristics as discussed by the authors, which is of particular relevance in the case of EAS simulations.
Abstract: The reliability of model calculations is of considerable significance because at energies above those attained by accelerators only model predictions enable us to extract primary cosmic ray characteristics. Different phenomenological models based on the quark-gluon picture of hadron interactions are of use now as a foundation for experimental data analysis at energies > 10 15 eV. In this paper we consider the present status of quark-gluon string (QGS) model with allowance made for semihard processes and (in the framework of so advanced model) discuss experimental data obtained at energies 10 15 ÷ 10 19 eV. In doing so we assume mass composition following from the diffusion notions of cosmic ray propagation through the Galaxy. Some general problems of EAS simulation and among them the simulation of electron-photon cascades are also discussed.
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Marcos Daniel Actis1, G. Agnetta2, Felix Aharonian3, A. G. Akhperjanian +682 more•Institutions (109)
TL;DR: The ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes as mentioned in this paper, which is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100GeV and above 100 TeV.
Abstract: Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.
1,006 citations
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...01 [87], QGSJet-II [88, 89] and SIBYLL 2....
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TL;DR: In this article, the authors present a detailed analysis of the performance of the Large Hadron Collider (CMS) at 14 TeV and compare it with the state-of-the-art analytical tools.
Abstract: CMS is a general purpose experiment, designed to study the physics of pp collisions at 14 TeV at the Large Hadron Collider (LHC). It currently involves more than 2000 physicists from more than 150 institutes and 37 countries. The LHC will provide extraordinary opportunities for particle physics based on its unprecedented collision energy and luminosity when it begins operation in 2007. The principal aim of this report is to present the strategy of CMS to explore the rich physics programme offered by the LHC. This volume demonstrates the physics capability of the CMS experiment. The prime goals of CMS are to explore physics at the TeV scale and to study the mechanism of electroweak symmetry breaking--through the discovery of the Higgs particle or otherwise. To carry out this task, CMS must be prepared to search for new particles, such as the Higgs boson or supersymmetric partners of the Standard Model particles, from the start-up of the LHC since new physics at the TeV scale may manifest itself with modest data samples of the order of a few fb−1 or less. The analysis tools that have been developed are applied to study in great detail and with all the methodology of performing an analysis on CMS data specific benchmark processes upon which to gauge the performance of CMS. These processes cover several Higgs boson decay channels, the production and decay of new particles such as Z' and supersymmetric particles, Bs production and processes in heavy ion collisions. The simulation of these benchmark processes includes subtle effects such as possible detector miscalibration and misalignment. Besides these benchmark processes, the physics reach of CMS is studied for a large number of signatures arising in the Standard Model and also in theories beyond the Standard Model for integrated luminosities ranging from 1 fb−1 to 30 fb−1. The Standard Model processes include QCD, B-physics, diffraction, detailed studies of the top quark properties, and electroweak physics topics such as the W and Z0 boson properties. The production and decay of the Higgs particle is studied for many observable decays, and the precision with which the Higgs boson properties can be derived is determined. About ten different supersymmetry benchmark points are analysed using full simulation. The CMS discovery reach is evaluated in the SUSY parameter space covering a large variety of decay signatures. Furthermore, the discovery reach for a plethora of alternative models for new physics is explored, notably extra dimensions, new vector boson high mass states, little Higgs models, technicolour and others. Methods to discriminate between models have been investigated. This report is organized as follows. Chapter 1, the Introduction, describes the context of this document. Chapters 2-6 describe examples of full analyses, with photons, electrons, muons, jets, missing ET, B-mesons and τ's, and for quarkonia in heavy ion collisions. Chapters 7-15 describe the physics reach for Standard Model processes, Higgs discovery and searches for new physics beyond the Standard Model
973 citations
TL;DR: In this article, the authors describe the changes required to the model to reproduce in detail the new data available from LHC and the consequences in the interpretation of these data, in particular the effect of the collective hadronization in p-p scattering.
Abstract: EPOS is a Monte-Carlo event generator for minimum bias hadronic interac- tions, used for both heavy ion interactions and cosmic ray air shower simulations. Since the last public release in 2009, the LHC experiments have provided a number of very inter- esting data sets comprising minimum bias p-p, p-Pb and Pb-Pb interactions. We describe the changes required to the model to reproduce in detail the new data available from LHC and the consequences in the interpretation of these data. In particular we discuss the effect of the collective hadronization in p-p scattering. A different parametrization of flow has been introduced in the case of a small volume with high density of thermalized matter (core) reached in p-p compared to large volume produced in heavy ion collisions. Both parametrizations depend only on the geometry and the amount of secondary particles en- tering in the core and not on the beam mass or energy. The transition between the two flow regimes can be tested with p-Pb data. EPOS LHC is able to reproduce all minimum bias results for all particles with transverse momentum from pt = 0 to a few GeV/c.
939 citations
TL;DR: In this paper, the semi-inclusive reaction e(+)p -> e(+p) Xp was studied with the ZEUS detector at HERA with an integrated luminosity of 128 pb(-1) and the final-state proton carried a large fraction of the incoming proton energy, x(L) > 032, and its transverse momentum squared satisfied p(T)(2) <05GeV(2).
Abstract: The semi-inclusive reaction e(+)p -> e(+) Xp was studied with the ZEUS detector at HERA with an integrated luminosity of 128 pb(-1) The final-state proton, which was detected with the ZEUS leading proton spectrometer, carried a large fraction of the incoming proton energy, x(L) > 032, and its transverse momentum squared satisfied p(T)(2) <05GeV(2); the exchanged photon virtuality, Q(2), was greater than 3 GeV2 and the range of the masses of the photon-proton system was 45
383 citations
01 Jan 2006
TL;DR: The QGSJET model has been successfully used by different groups in the field of high energy cosmic rays as discussed by the authors, and the first general update of the model is devoted to the main improvement connected to an account for non-linear interaction effects which are of crucial importance for reliable model extrapolation into the ultra-high energy domain.
Abstract: Since a number of years the QGSJET model has been successfully used by different groups in the field of high energy cosmic rays. Current work is devoted to the first general update of the model. The key improvement is connected to an account for non-linear interaction effects which are of crucial importance for reliable model extrapolation into the ultra-high energy domain. The proposed formalism allows to obtain a consistent description of hadron-hadron cross sections and hadron structure functions and to treat non-linear effects explicitly in individual hadronic and nuclear collisions. Other ameliorations concern the treatment of low mass diffraction, employment of realistic nuclear density profiles, and re-calibration of model parameters using a wider set of accelerator data.
343 citations
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437 citations
TL;DR: In this paper, the authors analyzed the Galactic magnetic field based on the large amount of pulsar rotation measures (RMs) now available, and regions of the sky suspected of producing anomalous RMs are discussed.
Abstract: The Galactic magnetic field is analyzed based on the large amount of pulsar rotation measures (RMs) now available, and regions of the sky suspected of producing anomalous RMs are discussed. The North Polar Spur appears to cause large positive RMs in the region l between 0 and 60 deg and b between 0 and 60 deg, and thus causes a systematic bias in modeling if the pulsars in the region are not flagged. Using only unflagged pulsars within D = 3 kpc and a longitudinal model of the local field, the strength is found to be B(0) = 1.6 + or - 0.3 microgauss in the direction l(B) = 96 deg + or - 4 deg, with a reversal at D(r) = 600 + or - 80 pc toward the inner Galaxy. A concentric-ring model is found to be superior to a bisymmetric spiral model as a fit to the data without the 3 kpc restriction, with a strength of B0 = 1.3 + or - 0.2 microgauss at the position of the sun and a reversal at D(r) = 650 + or - 90 pc toward the Galactic center. 33 refs.
281 citations
TL;DR: The objective here is the prediction of the energy dependence of crtot from the QCD parton model using a diffractive treatment of pp scattering, and finds that the semihard QCD processes associated with minijets lead to a rapid increase in the pp and pp total cross sections with increasing y/J.
Abstract: We show that parton-parton scattering processes in QCD drive a rapid increase in the proton-proton scattering cross section at high energies, and use a diffraction-scattering formalism to obtain quantitative predictions for ${\ensuremath{\sigma}}_{\mathrm{tot}}$, ${\ensuremath{\sigma}}_{\mathrm{inel}}$, and ${\ensuremath{\sigma}}_{\mathrm{el}}$ at Superconducting Super Collider and cosmic-ray energies. We also predict a very rapid increase in the number of minijet events with \ensuremath{\surd}s .
182 citations
TL;DR: In this article, the authors argue that the onset of this effect is observed at subteraelectronvolt energies via an increase in the rapidity distribution near y=0, an increase of 〈pT〉 with energy, and a correlation between multiplicity.
Abstract: Cross sections for the production of secondaries with large transverse momentum can become comparable to the total cross section in the teraelectronvolt energy range. We argue that the onset of this effect is observed at subteraelectronvolt energies via (i) an increase in the rapidity distribution near y=0, (ii) an increase of 〈pT〉 with energy, and (iii) a correlation between 〈pT〉 and multiplicity. We discuss the implications for future hadron colliders and cosmic-ray experiments in the corresponding energy range.
139 citations
TL;DR: The value of the proton-air nuclei inelastic cross section (σ in p-air) has been determined assuming the validity of quasi-Feynman scaling of particle production in the fragmentation region.
Abstract: Based on an analysis of the extensive air shower data accumulated over the last ten years at Akeno Cosmic Ray Observatory, the value of the proton-air nuclei inelastic cross section (${\mathrm{\ensuremath{\sigma}}}_{\mathrm{in}}^{\mathit{p}\mathrm{\ensuremath{-}}\mathrm{air}}$) has been determined assuming the validity of quasi-Feynman scaling of particle production in the fragmentation region. The energy dependence of ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{in}}^{\mathit{p}\mathrm{\ensuremath{-}}\mathrm{air}}$ can be represented as 290(E/1 TeV${)}^{0.052}$ mb in the energy interval ${10}^{16.2}$--${10}^{17.6}$ eV, where E is the incident proton energy. The total p-p cross section (${\mathrm{\ensuremath{\sigma}}}_{\mathrm{tot}}^{\mathit{p}\mathrm{\ensuremath{-}}\mathit{p}}$), derived using the nuclear distribution function obtained from the shell model, increases with energy as 38.5+1.37 ${\mathrm{ln}}^{2}$(\ensuremath{\surd}s /10 GeV) mb.
136 citations