نتایج جستجو برای: cosmic ray meson
تعداد نتایج: 337718 فیلتر نتایج به سال:
Diffuse interstellar clouds show large abundances of H3 which can be maintained only by a high ionization rate of H2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high cosmic-ray flux, and a large amount of energy residing in cosmic rays. In this paper we find that the standard propagated cosmic-ray spectrum predicts an ionization...
We report high-resolution observations made in interplanetary space of 83-284 MeV per nucleon galactic cosmic-ray iron isotopes and directly establish that 56Fe is the dominant cosmic-ray Fe isotope. We find the following percentage abundances for Fe at the cosmic-ray source: 54Fe = 9(+8, -5)%, 55Fe:::; 7%, 56Fe = 91(+5, -11)%, 57Fe:::; 8%, and 58Fe:::; 6%. When compared to calculated nucleosyn...
Contribution of nearby pulsars to the cosmic rays observed at Earth has been studied. It is found that the experimental bound on amplitude of cosmic ray anisotropy may produce significant constraint on the efficiency of converting pulsar rotational energy to emitted particles kinetic energy. Cosmic ray fluxes from two well known nearby gamma ray pulsars, namely the Vela and Geminga pulsars, are...
EGRET data on the Gamma ray emission from the inner Galaxy have shown a rather flat spectrum. This spectrum extends to about 50 GeV in photon energy. It is usually assumed that these gamma-rays arise from the interactions of cosmic ray nuclei with ambient matter. Cosmic Ray particles have been observed up to 3 10 20 eV, with many arguments suggesting, that up to about 3 10 18 eV they are of Gal...
Study of B meson (meson with the bottom quark flavor) in Large Hadron Collider (LHC) is of special importance so that the detector LHCb is devoted to investigate these types of mesons. For this reason, in this paper we will study the production process of this meson in a phenomenological approach using the experimental data from electron-positron annihilation. In this regards, we shall calculat...
Cosmic ray particles with energies in excess of 10 eV have been detected. The sources as well as the physical mechanism(s) responsible for endowing cosmic ray particles with such enormous energies are unknown. This report gives a review of the physics and astrophysics associated with the questions of origin and propagation of these EHE cosmic rays in the Universe. After a brief review of the ob...
Deviation angles of secondary electrons and muons in simulated extensive air showers were studied. The angles have wide distribution, whose width depends on energy cuts imposed on shower particles. In this work, variation of deviation angles with the energy of secondary particles, shower energy, primary direction, and core distance was investigated. The results put limitations on application ...
The isotopes of lithium, beryllium, and boron (LiBeB) are known in nature to be produced primarily by CNO spallation and a a fusion from interactions between cosmic rays and interstellar nuclei. While the dominant source of LiBeB isotopes in the present epoch is cosmic-ray interactions, other sources are known to exist, including the production of Li from big bang nucleosynthesis. Precise obser...
30TH INTERNATIONAL COSMIC RAY CONFERENCE Cosmic-ray helium intensities over the solar cycle from ACE
Observations of cosmic-ray helium energy spectra provide important constraints on cosmic ray origin and propagation. However, helium intensities measured at Earth are affected by solar modulation, especially below several GeV/nucleon. Observations of helium intensities over a solar cycle are important for understanding how solar modulation affects galactic cosmic ray intensities and for separat...
We give a review of cosmic ray propagation models. It is shown that the development of the theory of cosmic ray origin leads inevitably to the conclusion that cosmic ray propagation in the Galaxy is determined by effective particle scattering, which is described by spatial diffusion. The Galactic Disk is surrounded by an extended halo, in which cosmic rays are confined before escaping into inte...
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