Atmospheric Muon Spectrum Research Articles

Examination of Calculations of the Atmospheric Muon and Neutrino Spectra Using New Measurements

The atmospheric muon and neutrino fluxes at energies from 10 GeV to 10 PeV are calculated with the Kimel–Mokhov (KM), SIBYLL 2.1, EPOS LHC, and QGSJET-II hadronic models for known parameterizations of the cosmic ray spectra by Zatsepin--Sokolskaya and Hillas–Gaisser. The calculations with the KM, EPOS LHC, and SIBYLL 2.1 models are agree well with the measurements of the atmospheric muon spectra in IceCube and IceTop experiments. The measurement of high-energy muon spectra indicates the presence of the prompt muon component at energies above 500 TeV, which is well reproduced in calculations with the quark-gluon string model. The calculations of the atmospheric muon neutrino spectrum performed for the KM, EPOS LHC, and SIBYLL 2.1 models give good fit with the measurement data of IceCube, ANTARES, and Super-Kamiokande experiments.

High-energy atmospheric muon flux calculations in comparison with recent measurements

Recently the atmospheric muon spectra at high energies were reconstructed for two ranges of zenith angles, basing on the events collected with the IceCube detector. These measurements reach high energies at which the contribution to atmospheric muon fluxes from decays of short-lived hadrons is expected. Latest IceCube measurements of the high-energy atmospheric muon spectrum indicate the presence of prompt muon component at energies above 500 TeV.

Testing of the VENUS 4.12, DPMJET 2.55, QGSJET II-03 and SIBYLL 2.3 hadronic interaction models via help of the atmospheric vertical muon spectra

Uncertainties of the model energy spectra of the most energetic secondary π± -mesons (and K ± -mesons) are discussed. Computer simulations of the partial energy spectra of the atmospheric vertical muons induced by primary cosmic particles with various fixed energies in interval 102 −107 GeV in terms of the VENUS 4.12, DPMJET 2.55, QGSJET II-03 and SIBYLL 2.3 models had been carried out with help of CORSIKA package. These partial spectra should be convoluted with the contemporary spectra of the primary cosmic particles. Results of simulations are compared with the contemporary atmospheric vertical muon flux data. Comparison shows that all models underestimate production of secondary π± -mesons (and K ± -mesons) by factor of ∼ 2 at the most high energies. This underestimation induces more rapid development of extensive air showers in the atmosphere and results in uncertainties in estimates of energy and composition of the primary cosmic particles.

Identify signatures of underground muons from atmospheric charm: Simulation study

Muons from the “prompt” decays of charmed mesons in cosmic ray air showers start to show abundance on the atmospheric muon spectrum from few tens of TeV. Study of these prompt muons have broader interest in particle and astroparticle physics. The measurement of prompt muon in air showers is challenging because of their low production rate and the large amount of conventional muons produced in company with them. This paper describes the simulation study of a method that identifies prompt muon signatures based on the pattern of stochastic energy losses by muon bundles in deep under ice. The systematics associated with different hadronic interaction models and cosmic ray primary composition assumptions were estimated. Using IceCube as an example, we briefly discussed the challenge of using this method in experimental data analysis.

BEAMING NEUTRINOS AND ANTI-NEUTRINOS ACROSS THE EARTH TO DISENTANGLE NEUTRINO MIXING PARAMETERS

A MINOS result seemed to hint a different anti-neutrino mass splitting and mixing angle with respect to the neutrino ones, offering a hint for a CPT violation in lepton sector. However more recent MINOS data reduced the neutrino-antineutrino differences leading to a narrow discrepancy almost compatible with no CPT violation, hard to be disentangled. Moreover last a few years of OPERA activity on tau appearance is still un-probed (one unique event). Both flavor muon-tau mixing, tau appearance and eventual CPT violation disentanglement need more tools to be enhanced. Atmospheric muon neutrino spectra and anisotropy in Deep Core at ten-tens GeV (yet unpublished) may test the muon-tau conversion but they can hardly reveal such last tiny MINOS CPT asymmetry. We show how the longest baseline neutrino oscillation available, crossing most of the Earth diameter, within an OPERA-like experiment from CERN (or FERMILAB) to ICECUBE-Deep Core neutrino detector at 21 GeV energy, may at best disentangle even last tiny CPT violation (within 6 sigma a year) while testing at highest rate tau-antitau appearance. We propose the muon neutrino disappearance or (for any CPT violation) the partial anti-muon appearance at the longest distances. Such a tuned detection experiment may lead to a clear and strong signature of tau or anti-tau generation (even within its neutral current noise background events): nearly one antitau or two tau a day. The tau appearance signal is above (or within) 10 sigma a year, even for 1% OPERA-like experiment. Peculiar configurations for theta_13 angle test and hierarchy neutrino mass test may also be addressed by a Deep Core-PINGU array detector observing electron neutrino shower at 6 GeV neutrino energy windows.

ATMOSPHERIC MUON FLUX AT PEV ENERGIES

In the near future, the energy region above few hundreds of TeV may really be accessible for measurements of the atmospheric muon spectrum with IceCube array. Therefore, one expects that muon flux uncertainties above 50 TeV, related to a poor knowledge of charm production cross-sections and insufficiently examined primary spectra and composition, will be diminished. We give predictions for the very high-energy muon spectrum at sea level, obtained with the three hadronic interaction models, taking into account also the muon contribution due to decays of the charmed hadrons.

Muons in IceCube

The IceCube detector allows for the first time a measurement of atmospheric muon and neutrino energy spectra from tens of GeV up to the PeV range. The lepton flux in the highest energy region depends on both the primary cosmic ray composition around the “knee” and the contribution from prompt decays of mostly charmed hadrons produced in air showers. It is demonstrated here that a direct measurement of the atmospheric muon spectrum in the region above 100 TeV is feasible using data that is already available.

L3+C: status of the data analysis

The L3+C muon spectrometer is a delicate detector setup to record cosmic ray muons. Several results on atmospheric muon spectrum, Moon shadow and anti-proton/proton ratio, muon flare detection, etc, have been achieved. The study of some other physics topics, such as e.g. the search for exotic phenomena, the research on muon bundle events, are still going on. The status of the L3+C data analysis is presented.

Uncertanties of atmospheric high-energy muon fluxes and spectrum of primary cosmic rays

New results of calculations of nucleon, π-and K-meson, and muon fluxes generated during high energy cosmic ray interactions with the Earth’s atmosphere are presented. The calculations are based on the method of solving the nuclear cascade equations with allowance for non-scaling behavior of inclusive hadron production cross sections, increase of cross sections of inelastic hadron-nucleus collisions with energy, and non-power-law character of primary spectrum. The hadron and muon fluxes are calculated at different atmospheric altitude levels for several spectral models and compositions of primary cosmic rays. Results of calculations are compared with recent measurements using the L3+Cosmic and CosmoALEPH facilities.

Cosmic-ray spectra of primary protons and high altitude muons deconvolved from observed atmospheric gamma rays

We have observed atmospheric gamma rays from 30 GeV to 8 TeV, using emulsion chambers at balloon altitudes, accumulating the largest total exposure in this energy range to date, $S\ensuremath{\Omega}T\ensuremath{\sim}6.66\text{ }\text{ }{\mathrm{m}}^{2}\text{ }\mathrm{sr}\text{ }\mathrm{day}$. At very high altitudes, with residual overburden only a few $\mathrm{g}\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$, atmospheric gamma rays are mainly produced by a single interaction of primary cosmic rays with overlying atmospheric nuclei. Thus, we can use these gamma rays to study the spectrum of primary cosmic rays and their products in the atmosphere. From the observed atmospheric gamma-ray spectrum, we deconvolved the primary cosmic-ray proton spectrum, assuming appropriate hadronic interaction models. Our deconvolved proton spectrum covers the energy range from 200 GeV to 50 TeV, which fills a gap in the currently available primary cosmic-ray proton spectra. We also estimated the atmospheric muon spectrum above 30 GeV at high altitude from our gamma-ray spectrum, almost without reference to the primary cosmic rays, and compared the estimated flux with direct muon observations below 20 GeV.

Test of Monte-Carlo model with the L3+C muon spectrum measurement

The paper shows good agreement between the atmospheric muon spectra measured by L3+C and the COMUGEN Monte-Carlo model. The atmospheric neutrino spectrum is inferred.

Atmospheric muon measurements using the OKAYAMA telescope

The atmospheric muon spectrum has been measured at sea level using a magnet spectrometer called the OKAYAMA telescope. The OKAYAMA telescope is able to point at any azimuth and zenith angle and to measure the muon energy and charge sign. We report the absolute atmospheric muon differential energy spectrum, charge ratio and azimuthal angular dependences.

Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV

The absolute muon flux between 20 and 3000 GeV was measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 0 to 58 0 . Due to the large exposure of about 150 m 2 sr d and the excellent momentum resolution of the L3 muon chamber system, the muon flux was determined with a precision of 2.3 % at 150 GeV in the vertical direction. The ratio of positive to negative muons was studied between 20 and 500 GeV. The average vertical muon charge ratio is found to be 1.285 ± 0.003 (stat.)± 0.019 (sys.)

Measurement of the atmospheric muon spectrum from 20 to 3000 GeV

The absolute muon flux between 20 and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0° to 58°. Due to the large exposure of about 150m2sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3% at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 and 500 GeV, and the average vertical muon charge ratio is found to be 1.285±0.003(stat.)±0.019(syst.).

Measurement of the atmospheric muon spectrum from 20 to 3000 GeV

The absolute muon flux between 20 and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0° to 58°. Due to the large exposure of about 150 m2sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3% at 150 GeV in the vertical direction is achieved.The ratio of positive to negative muons is studied between 20 and 500 GeV, and the average vertical muon charge ratio is found to be 1.285±0.003(stat.)±0.019(syst.).

Energy spectra of atmospheric muons measured with the CAPRICE98 balloon experiment

The measurement of the atmospheric muon spectrum is currently of great interest because of the study of atmospheric neutrinos and the claim of neutrino oscillations made in 1998 by the Super-Kamiokande Collaboration. A measurement of the muon flux is an indirect measure of the neutrino flux. Therefore, it can be used to improve the calculation of the atmospheric neutrino flux, which in turn can be compared with the observed neutrino rates in underground detectors. This article reports a new measurement of the m 1 and m 2 spectra at several atmospheric depths in the momentum ranges 0.3‐20 GeV/c and 0.3‐40 GeV/c, respectively. The data were collected by the balloon-borne experiment CAPRICE98 during the ascent of the payload on 28 May 1998 from Fort Sumner, N. M. The experiment used the NMSU-WIZARD/CAPRICE 98 balloon-borne magnet spectrometer equipped with a gas ring imaging Cherenkov detector and a silicon-tungsten calorimeter.

Measurements of atmospheric muon spectra at mountain altitude

We report new measurements of absolute fluxes of atmospheric muons at mountain altitude. The measurements were carried out with the BESS detector at the top of Mt. Norikura, 2 770 m above sea level, in Japan. The overall errors were less than 10%. The measured results are discussed in comparison with theoretical calculations.