128 research outputs found
Simplest Validation of the HIJING Monte Carlo Model
Fulfillment of the energy-momentum conservation law, as well as the charge,
baryon and lepton number conservation is checked for the HIJING Monte Carlo
program in -interactions at 200, 5500, and 14000 GeV. It is
shown that the energy is conserved quite well. The transverse momentum is not
conserved, the deviation from zero is at the level of 1--2 GeV/c, and it is
connected with the hard jet production. The deviation is absent for soft
interactions.
Charge, baryon and lepton numbers are conserved.
Azimuthal symmetry of the Monte Carlo events is studied, too. It is shown
that there is a small signature of a "flow". The situation with the symmetry
gets worse for nucleus-nucleus interactions.Comment: 8 pages, 6 figure
The Possibility of New Physics in pp Elastic Scattering at LHC
Modern models of high energy elastic hadron-hadron scattering predict an
oscillation character of differential cross sections at the LHC energy of 14
TeV and at a sufficiently high momentum transfer. The Totem collaboration did
not see the oscillations at 7 TeV. According to some predictions, the
oscillations are weak at 7 TeV in the studied 4-momentum transfer range (|t|<
2.5 GeV). They may be beyond the range of the experiment. But a direct
extension of the Totem collaboration data on the pp-scattering at 7 TeV above
|t|\sim 2.5 GeV contradicts previous measurements. Thus the collaboration
can discover either the oscillations at large |t| or a change of the
differential cross section behavior in the high |t| region (|t|> 2.5 GeV).Comment: 3 page
Calculation of light nucleus reaction cross sections in Geant4
Total reaction cross sections of light projectile nucleus (H-2, H-3, He-3 and
He-4) interactions with nuclei are calculated using Geant4 models, and compared
with experimental data. It is shown that the models give various predictions at
low energies, in the region of the Coulomb barrier. "Shen model" (W.-Q. Shen et
al., Nucl. Phys. {\bf A491} (1989) 130) is identified as an improvement over
other models.Comment: 2 pages text, 8 figure
Production of strange particles in hadronic interactions
The NA61/SHINE collaboration has recently published high precision data on
production of and mesons, protons, antiprotons and
hyperons in interactions at 20, 31, 40, 80 and 158 GeV/c, and in
interactions at 31 GeV/c. The collaboration also presented
experimental data on production of particles - , , ,
, and in collisions at 158 and 350
GeV/c. The collaboration has compared these data with various Monte Carlo model
calculations: UrQMD, EPOS, GiBUU, and others.
All of the models have various problems. The latest version of the FTF
(Fritiof) model of Geant4 solves most of these problems. In the FTF model, we
have improved the fragmentation of quark-gluon strings with small masses and
introduced dependencies of probabilities of strange mesons and
baryon-antibaryon pair's creation on string masses. Due to these changes, we
describe the data of the NA61/SHINE collaboration on particle production in
, and interactions.
The improved Geant4 FTF model also well reproduces experimental data on
inclusive cross sections of and production in
antiproton-proton interactions at various energies. The modified FTF model
allows one to simulate realistic processes with two particle productions -
, , , and , which will be studied in the future by the
PANDA experiment at FAIR (GSI, Germany).Comment: 10 pages, 8 figures, IWNT-37, Rila, 2018, Bulgari
Dynamics of Anti-Proton -- Protons and Anti-Proton -- Nucleus Reactions
A short review of simulation results of anti-proton-proton and
anti-proton-nucleus interactions within the framework of Geant4 FTF (Fritiof)
model is presented. The model uses the main assumptions of the
Quark-Gluon-String Model or Dual Parton Model. The model assumes production and
fragmentation of quark-anti-quark and diquark-anti-diquark strings in the
mentioned interactions. Key ingredients of the model are cross sections of
string creation processes and an usage of the LUND string fragmentation
algorithm. They allow one to satisfactory describe a large set of experimental
data, especially, a strange particle production, Lambda hyperons and K mesons.Comment: 7 pages, 8 figure
Tuning of the GEANT4 FRITIOF (FTF) Model Using NA61/SHINE Experimental Data
The NA61/SHINE collaboration measured inclusive cross sections of \pi^+ and
\pi^- meson production in the interactions of 31 GeV/c protons with carbon
nuclei at forward emission angles (0 - 420 mrad). The collaboration also
presented predictions of Monte Carlo models - FLUKA, VENUS and UrQMD, in
comparison with the data. A careful analysis shows that deviations of the FLUKA
and VENUS predictions from the data have different tendencies. The worst
description of the data was observed for the UrQMD model results.
All the models assume the creation of quark-gluon strings in the
interactions, but it is complicated to analyze the models in order to find the
source of the deviations. Thus, the quark-gluon string model - FRITIOF (FTF) -
was implemented in the GEANT4 toolkit and is used to understand the deviations
mentioned above. It was found that the most important factor influencing the
FTF calculations is the sampling of quark-gluon string masses. The other
factors/parameters are not essential for a description of the data. Also, a
good description of the data is achieved by the FTF model.Comment: 5 page
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