► New analysis of charge ratio of muons. ► Reduced contribution of positive kaons. ► Implications for atmospheric neutrinos.
Interpretation of measurements of the muon charge ratio in the TeV range ...depends on the spectra of protons and neutrons in the primary cosmic radiation and on the inclusive cross sections for production of π± and K± in the atmosphere. Recent measurements of the spectra of cosmic-ray nuclei are used here to estimate separately the energy spectra of protons and neutrons and hence to calculate the charge separated hadronic cascade in the atmosphere. From the corresponding production spectra of μ+ and μ− the μ+/μ− ratio is calculated and compared to recent measurements. The comparison leads to a determination of the relative contribution of kaons and pions. Implications for the spectra of νμ and ν¯μ are discussed.
We present a new version of the hadron interaction event generator sibyll. While the core ideas of the model have been preserved, the new version handles the production of baryon pairs and leading ...particles in a new way. In addition, production of charmed hadrons is included. Updates to the model are informed by high-precision measurements of the total and inelastic cross sections with the forward detectors at the LHC that constrain the extrapolation to ultrahigh energy. Minimum-bias measurements of particle spectra and multiplicities support the tuning of fragmentation parameters. This paper demonstrates the impact of these changes on air-shower observables such as Xmax and Nμ, drawing comparisons with other contemporary cosmic-ray interaction models.
This review focuses on high-energy cosmic rays in the PeV energy range and above. Of particular interest is the knee of the spectrum around 3 PeV and the transition from cosmic rays of Galactic ...origin to particles from extra-galactic sources. Our goal is to establish a baseline spectrum from 1014 to 10^20 eV by combining the results of many measurements at different energies. In combination with measurements of the nuclear composition of the primaries, the shape of the energy spectrum places constraints on the number and spectra of sources that may contribute to the observed spectrum.
An efficient method for calculating inclusive conventional and prompt atmospheric leptons fluxes is presented. The coupled cascade equations are solved numerically by formulating them as matrix ...equation. The presented approach is very flexible and allows the use of different hadronic interaction models, realistic parametrizations of the primary cosmic-ray flux and the Earth's atmosphere, and a detailed treatment of particle interactions and decays. The power of the developed method is illustrated by calculating lepton flux predictions for a number of different scenarios.
Atmospheric neutrinos are an important background to astrophysical neutrino searches, and are also of considerable interest in their own right. This paper points out that the contribution to ...conventional atmospheric νe of the rare semileptonic decay of KS becomes significant at high energy. Although the KS→πeν branching ratio is very small, the short KS lifetime leads to a high critical energy, so that, for vertical showers, the inclusion of KS semileptonic decay increases the conventional νe flux by ≈30% at energies above 100TeV. In this paper, we present calculations of the flux of νe from KS. At energies above their critical energies, the νe fluxes from kaon decay may be simply related to the kaon semileptonic widths; this leads to a near-equality between the flux of νe from K+,KL and KS.
Muons and neutrinos from cosmic ray interactions in the atmosphere originate from decays of mesons in air-showers. sibyll-2.3c aims to give a precise description of hadronic interactions in the ...relevant phase space for conventional and prompt leptons in light of new accelerator data, including that from the LHC. sibyll is designed primarily as an event generator for use in simulation of extensive air showers. Because it has been tuned for forward physics as well as the central region, it can also be used to calculate inclusive fluxes. The purpose of this paper is to describe the use of sibyll-2.3c for calculation of fluxes of atmospheric leptons.
High energy cosmic rays: sources and fluxes Stanev, Todor; Gaisser, Thomas K.; Tilav, Serap
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2014, Letnik:
742
Journal Article
Recenzirano
We discuss the production of a unique energy spectrum of the high energy cosmic rays detected with air showers by shifting the energy estimates of different detectors. After such a spectrum is ...generated we fit the spectrum with three or four populations of cosmic rays that might be accelerated at different cosmic ray sources. We also present the chemical composition that the fits of the spectrum generates and discuss some new data sets presented this summer at the ICRC in Rio de Janeiro that may require new global fits.
The intensity of TeV atmospheric muons and neutrinos depends on the temperature in the stratosphere. We show that the energy dependence in the 100 TeV range of the correlation with temperature is ...sensitive to the fraction of muons and neutrinos from decay of charmed hadrons. We discuss the prospects for using the temperature effect as observed in gigaton neutrino detectors to measure the charm contribution.
Charm production in SIBYLL Riehn, F; Engel, R; Fedynitch, A ...
EPJ Web of Conferences,
01/2015, Letnik:
99
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
SIBYLL 2.1 is an event generator for hadron interactions at the highest energies. It is commonly used to analyze and interpret extensive air shower measurements. In light of the first detection of ...PeV neutrinos by the IceCube collaboration the inclusive fluxes of muons and neutrinos in the atmosphere have become very important. Predicting these fluxes requires understanding of the hadronic production of charmed particles since these contribute significantly to the fluxes at high energy through their prompt decay. We will present an updated version of SIBYLL that has been tuned to describe LHC data and extended to include the production of charmed hadrons.
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