652 research outputs found
Flux of atmospheric muons: Comparison between AIRES simulations and CAPRICE98 data
We report on a comparison between the flux of muons in the atmosphere
measured by the CAPRICE98 experiment and simulations performed with the air
shower simulation program AIRES. To reduce systematic uncertainties we have
used as input the primary fluxes of protons and helium nuclei also measured by
the CAPRICE98 experiment. Heavy nuclei are also taken into account in the
primary flux, and their contribution to the muon flux is discussed. The results
of the simulations show a very good agreement with the experimental data, at
all altitudes and for all muon momenta. With the exception of a few isolated
points, the relative differences between measured data and simulations are
smaller than 20 %; and in all cases compatible with zero within two standard
deviations. The influence of the input cosmic ray flux on the results of the
simulations is also discussed. This report includes also an extensive analysis
of the characteristics of the simulated fluxes.Comment: Accepted for publication in Physical Review
Progresses in the validation of the FLUKA atmospheric neutrino flux calculations
The FLUKA calculation of the atmospheric neutrino fluxes have been
cross-checked by comparing predictions on lepton fluxes in atmosphere to
experimental data. The dependence of predicted neutrino fluxes on the shape and
normalization of primary spectrum is also investigatedComment: Presented at TAUP2001 (Sep. 8-12, Assergi, Italy). 5 pages, 1 figur
Spatial Resolution of Double-Sided Silicon Microstrip Detectors for the PAMELA Apparatus
The PAMELA apparatus has been assembled and it is ready to be launched in a
satellite mission to study mainly the antiparticle component of cosmic rays. In
this paper the performances obtained for the silicon microstrip detectors used
in the magnetic spectrometer are presented. This subdetector reconstructs the
curvature of a charged particle in the magnetic field produced by a permanent
magnet and consequently determines momentum and charge sign, thanks to a very
good accuracy in the position measurements (better than 3 um in the bending
coordinate). A complete simulation of the silicon microstrip detectors has been
developed in order to investigate in great detail the sensor's characteristics.
Simulated events have been then compared with data gathered from minimum
ionizing particle (MIP) beams during the last years in order to tune free
parameters of the simulation. Finally some either widely used or original
position finding algorithms, designed for such kind of detectors, have been
applied to events with different incidence angles. As a result of the analysis,
a method of impact point reconstruction can be chosen, depending on both the
particle's incidence angle and the cluster multiplicity, so as to maximize the
capability of the spectrometer in antiparticle tagging.Comment: 28 pages, 18 figures, submitted to Nuclear Instruments and Methods in
Physics Research
Kaluza-Klein Dark Matter and Galactic Antiprotons
Extra dimensions offer new ways to address long-standing problems in beyond
the standard model particle physics. In some classes of extra-dimensional
models, the lightest Kaluza-Klein particle is a viable dark matter candidate.
In this work, we study indirect detection of Kaluza-Klein dark matter via its
annihilation into antiprotons. We use a sophisticated galactic cosmic ray
diffusion model whose parameters are fully constrained by an extensive set of
experimental data. We discuss how fluxes of cosmic antiprotons can be used to
exclude low Kaluza-Klein masses.Comment: 14 pages, 7 figures, 3 table
Uncertainties on Atmospheric Neutrino Flux Calculations
The strong evidence of new physics coming from atmospheric neutrino
experiments has motivated a series of critical studies to test the robustness
of the available flux calculations. In view of a more precise determination of
the parameters of new physics, new and more refined flux calculations are in
progress. Here we review the most important sources of theoretical
uncertainties which affect these computations, and the attempts currently under
way to improve them.Comment: Extended version of talk given at NOW2000, Conca Specchiulla,
Otranto, Italy, Sep. 2000 Fig. 2 has been replace
Difference between radiative transition rates in atoms and antiatoms
We demonstrate that CP violation results in a difference of the partial decay
rates of atoms and antiatoms. The magnitude of this difference is estimated.Comment: 5 pages, 5 figure
Calculation Of Secondary Particles In Atmosphere And Hadronic Interactions
Calculation of secondary particles produced by the interaction of cosmic rays
with the nuclei of Earth's atmosphere pose important requirements to particle
production models. Here we summarize the important features of hadronic
simulations, stressing the importance of the so called ``microscopic''
approach, making explicit reference to the case of the FLUKA code. Some
benchmarks are also presented.Comment: 10 pages, 4 figures. Extended version of report given at the IInd
Workshop on Matter and anti-Matter, Trento, Oct. 200
Launch of the Space experiment PAMELA
PAMELA is a satellite borne experiment designed to study with great accuracy
cosmic rays of galactic, solar, and trapped nature in a wide energy range
protons: 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study
of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50
MeV-270 GeV) and search for antimatter with a precision of the order of 10^-8).
The experiment, housed on board the Russian Resurs-DK1 satellite, was launched
on June, 15, 2006 in a 350*600 km orbit with an inclination of 70 degrees. The
detector is composed of a series of scintillator counters arranged at the
extremities of a permanent magnet spectrometer to provide charge,
Time-of-Flight and rigidity information. Lepton/hadron identification is
performed by a Silicon-Tungsten calorimeter and a Neutron detector placed at
the bottom of the device. An Anticounter system is used offline to reject false
triggers coming from the satellite. In self-trigger mode the Calorimeter, the
neutron detector and a shower tail catcher are capable of an independent
measure of the lepton component up to 2 TeV. In this work we describe the
experiment, its scientific objectives and the performance in the first months
after launch.Comment: Accepted for publication on Advances in Space Researc
Measurement of the flux of atmospheric muons with the CAPRICE94 apparatus
A new measurement of the momentum spectra of both positive and negative muons
as function of atmospheric depth was made by the balloon-borne experiment
CAPRICE94. The data were collected during ground runs in Lynn Lake on the
19-20th of July 1994 and during the balloon flight on the 8-9th of August 1994.
We present results that cover the momentum intervals 0.3-40 GeV/c for negative
muons and 0.3-2 GeV/c for positive muons, for atmospheric depths from 3.3 to
1000 g/cm**2, respectively. Good agreement is found with previous measurements
for high momenta, while at momenta below 1 GeV/c we find latitude dependent
geomagnetic effects. These measurements are important cross-checks for the
simulations carried out to calculate the atmospheric neutrino fluxes and to
understand the observed atmospheric neutrino anomaly.Comment: 28 pages, 13 Postscript figures, uses revtex.sty, to appear in Phys.
Rev.
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