SearcharxivSearch

arXiv subjects

S. P. Mikheyev

Publications and source records attributed to S. P. Mikheyev.

7 recordsLinked to original sources

Search for muon signal from dark matter annihilations in the Sun with the Baksan Underground Scintillator Telescope for 24.12 years

We present a new dataset analysis of the neutrino experiment at the Baksan Underground Scintillator Telescope with muon energy threshold about 1 GeV for the longest exposure time toward the Sun. In search for a signal from self-annihilations of dark matter particles in the center of the Sun we use an updated sample of upward through-going muons for 24.12 years of live time. No observable excess has been found in measured muons relative to expected background from neutrinos of atmospheric origin. We present an improved data analysis procedure and describe it in detail. We set the 90\% C.L. new upper limits on expected neutrino and muon fluxes from dark matter annihilations in the Sun, on the corresponding annihilation rates and cross sections of their elastic scattering off proton.

astro-ph.HE

Test of Fermi Gas Model and Plane-Wave Impulse Approximation Against Electron-Nucleus Scattering Data

A widely used relativistic Fermi gas model and plane-wave impulse approximation are tested against electron-nucleus scattering data. Inclusive quasi-elastic cross section are calculated and compared with high-precision data for C, O, and Ca. A dependence of agreement between calculated cross section and data on a momentum transfer is shown. Results for the C(nu_mu,mu) reaction are presented and compared with experimental data of the LSND collaboration.

hep-ph

The cross-section of muon-nuclear inelastic interaction

It is shown that the combination of the structure functions $F_2$ predicted by the CKMT model at low and moderate values of $Q^2$ and MRS99 parton distribution functions at high $Q^2$ gives a good description of the data over complete measured region of $x$ and $Q^2$. Using these structure functions the main characteristics of the muon-nucleus inelastic scattering are calculated. Nuclear effects and contributions of the neutral current and $γ- Z$ interference are taken into account.

hep-ph

Comments on multiple scattering of high-energy muons in thick layers

We describe two independent methods to calculate the angular distribution of muons after traversing a thick scatterer due to multiple Coulomb scattering. Both methods take into account the nuclear size effect. We demonstrate a necessity to account for the nucleus extension as well as incoherent scattering on atomic electrons to describe the muon scattering at large angles in thick matter layers. The results of the two methods of calculations are in good agreement.

hep-ph

Parametric Resonance in Oscillations of Atmospheric Neutrinos?

We consider a solution of the atmospheric neutrino problem based on oscillations of muon neutrinos to sterile neutrinos: $ν_μ$ $\leftrightarrow$ $ν_s$. The zenith angle ($Θ$) dependences of the neutrino and upward-going muon fluxes in presence of these oscillations are studied. The dependences have characteristic form with two dips: at $\cos Θ= -0.6 ÷-0.2$ and $\cos Θ= -1.0 ÷-0.8$. The latter dip is due to parametric resonance in oscillations of neutrinos which cross the core of the earth. A comparison of predictions with data from the MACRO, Baksan and Super-Kamiokande experiments is given.

hep-ph

Vacuum oscillations of solar neutrinos: correlation between spectrum distortion and seasonal variations

Long length vacuum oscillations solution of the solar neutrino problem is discussed. We show that there is a strict correlation between a distortion of the neutrino energy spectrum and an amplitude of seasonal variations of the neutrino flux. The slope parameter which characterizes a distortion of the recoil electron energy spectrum in the Super-Kamiokande experiment and the seasonal asymmetry of the signal have been calculated in a wide range of oscillation parameters. The correlation of the slope and asymmetry gives crucial criteria for identification or exclusion of this solution. For the positive slope indicated by preliminary Super-Kamiokande data we predict (40 - 60) % enhancement of the seasonal variations.

hep-ph