Transcript Comparison Of High Energy Hadronic Interaction Models G. Battistoni(1), R. Ganugapati(2), A.Karle(2), J.

Comparison Of High Energy Hadronic Interaction Models
G. Battistoni(1), R. Ganugapati(2), A.Karle(2), J. L. Kelley(2), T. Montaruli(2,3)
(1) Univeristy of Milano & INFN, 20133, Milano, Italy
(2) University of Wisconsin, 53706, Madison, WI, USA
(3) on leave from University of Bari, 70126, Bari, Italy
Hadronic Interaction
Models for Shower
Development
The hadronic interaction models used in cosmic ray air
shower Monte Carlo codes are built based on various
theoretical scenarios. These can be checked by
accelerator experiments up to energies achievable by
colliders but must be extrapolated to higher energies. The
L3+C data (Ralph Engel, private communication) at lower
energies show that the the muon flux predicted using
different interaction models can differ by up to 30%.
Muon Intensity vs. Zenith Angle
Detecting Extra-Terrestrial
Neutrinos and understanding
Atmospheric Neutrino/Muon Fluxes
Differences of the model predictions when compared with
measurements are observed. This could be due to
differences in the physics of interaction models and how
the data are extrapolated to cosmic ray energies.
Therefore, more benchmarks with data and improvements
of the hadronic interaction models are necessary.
During the development of air showers, in the most
forward region a large fraction of the collision energy is
taken by the secondary particles. Here we show the
energy fraction distributions of various secondaries of
proton-Nitrogen collisions (charged pions, kaons, and
charmed particles when possible) after the first
interaction.
The main backgrounds for the detection of extraterrestrial
neutrino fluxes are the atmospheric muons and neutrinos
produced from the interaction of cosmic rays with the
atmosphere. The predicted atmospheric neutrino and muon
fluxes depend on the models used to describe these
interactions, and discrepancies become very large at high
energies (> 1 TeV). We have produced a detailed analysis of
the interaction models.
Kaons
Intensity vs. Zenith Angle of down-going muons
From ICRC 2003 (Paolo Desiati et al.). The simulated data using the
QGSJET-01 interaction model is multiplied by 1.3 in this plot. A larger
excess of experimental data with respect to MC is observed in the
horizontal region were possibly muons from prompt charm hadron decays
can contribute (not accounted for in MC).
Hence AMANDA observes more muons than predicted by QGSJET-01!
Transverse Momentum Plot
10 TeV Fixed Primary Energy
Ch. Pions
Air Shower
Development
100 TeV Fixed Primary Energy
Kaons
Ch. Pions
1 PeV Fixed Primary Energy
Ch. Pions
Kaons
Transverse Momentum (GeV)
Mean pT (MeV)
Charm (Meson+Baryon)
Esecondary/Eprimary>0.05 (region relevant for atmospheric showers)
Z-Moment
Charm (Meson+Baryon)
Average Multiplicity
ch. pions
ch. pions
kaons
Log10(Primary Energy) GeV
Account for spectral dependence
of CRs interacting with
atmospheric nuclei
kaons
Log10(Primary Energy) GeV
Charm (Meson+Baryon)
Conclusions
From the plots on secondary energy fractions we see that SIBYLL and FLUKA+DPMJET-III are in very
good agreement and in reasonable agreement with DPMJET-II for conventional mesons (charged pions
and kaons). However, QGSJET-01 and -II predict a lower energy fraction in the region where
secondaries take a very large fraction of the primary energy. This could explain the disagreement in the
AMANDA-II muon intensity distribution, since the depth of the detector selects higher energy
secondaries. For charmed hadrons, it seems that the implementation of DPMJET-II in CORSIKA
underestimates diffractive processes, especially for charmed baryons.
Acknowledgments
We would like to acknowledge Athina Meli for providing a version of CORSIKA
using DPMJET-II enabling charmed meson and baryon decays.
RMS pT(MeV)
Pions
446.50
287.43
Kaons
458.04
288.04
Charm Meson
467.33
289.01
Charm Baryon
467.624
289.02
The first plot on the left of this panel shows the pT distribution of
secondaries for p-Nitrogen interactions at 1 PeV. As indicated by
the mean values, the pT is on average larger for charmed secondaries.
This does not necessarily mean that the lateral distribution of
muons at the surface will be larger for muons from prompt
hadrons than conventional ones. This is demonstrated by the
plots on the right.
The plots on the right show the energy (almost equal to pL at these
energies) and lateral separation (from the primary direction) of
secondary muons produced in events with no charmed hadron (CONV
- dashed lines) and in events with charmed hadron production
(PROMPT) before (1st interaction only - pink lines) and after shower
development (blue lines). The plots select those muons that would
reach the AMANDA detector depth but quantities are given at the
surface of the Earth. These plots are obtained with CORSIKA
using the DPMJET interaction model for a fixed 1 PeV energy
primary proton and 65 degree zenith angle.