Comparison Of High Energy Hadronic Interaction Models

1
Comparison Of High Energy Hadronic Interaction
Models

• G. Battistoni(1), R. Ganugapati(2), A.Karle(2),
  J. L. Kelley(2), T. Montaruli(2,3)
• Univeristy of Milano INFN, 20133, Milano,
  Italy
• University of Wisconsin, 53706, Madison, WI, USA
• on leave from University of Bari, 70126, Bari,
  Italy

Hadronic Interaction Models for Shower Development
Muon Intensity vs. Zenith Angle

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 L3C 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. 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.
Detecting Extra-Terrestrial Neutrinos and
understanding Atmospheric Neutrino/Muon Fluxes
Air Shower Development
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 (gt 1 TeV). We have
produced a detailed analysis of the interaction
models.
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
100 TeV Fixed Primary Energy
1 PeV Fixed Primary Energy
Ch. Pions
Kaons
Kaons
Ch. Pions
Ch. Pions
Kaons
Transverse Momentum (GeV)
Mean pT (MeV)
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
Charm (MesonBaryon)
Charm (MesonBaryon)
Charm (MesonBaryon)
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.
Esecondary/Eprimarygt0.05 (region relevant for
atmospheric showers)
Conclusions From the plots on secondary energy
fractions we see that SIBYLL and FLUKADPMJET-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.
Average Multiplicity
Z-Moment
ch. pions
ch. pions
Account for spectral dependence of CRs
interacting with atmospheric nuclei
Acknowledgments We would like to acknowledge
Athina Meli for providing a version of
CORSIKA using DPMJET-II enabling charmed meson
and baryon decays.
kaons
kaons
Log10(Primary Energy) GeV
Log10(Primary Energy) GeV