Searcharxiv⌕ Search

arXiv subjects

S. Hussain

Publications and source records attributed to S. Hussain.

5 recordsLinked to original sources
arXiv2018

Cosmic-ray propagation in the turbulent intergalactic medium

Cosmic rays (CRs) may be used to infer properties of intervening cosmic magnetic fields. Conversely, understanding the effects of magnetic fields on the propagation of high-energy CRs is crucial to elucidate their origin. In the present work we investigate the role of intracluster magnetic fields on the propagation of CRs with energies between $10^{16}$ and $10^{18.5}$ eV. We look for possible signatures of a transition in the CR propagation regime, from diffusive to ballistic. Finally, we discuss the consequences of the confinement of high-energy CRs in clusters and superclusters for the production of gamma rays and neutrinos.

astro-ph.HE↗
arXiv2015

Conservation of Hamiltonian using Continuous Galerkin Petrov time discretization scheme

Continuous Galerkin Petrov time discretization scheme is tested on some Hamiltonian systems including simple harmonic oscillator, Kepler's problem with different eccentricities and molecular dynamics problem. In particular, we implement the fourth order Continuous Galerkin Petrov time discretization scheme and analyze numerically, the efficiency and conservation of Hamiltonian. A numerical comparison with some symplectic methods including Gauss implicit Runge-Kutta method and general linear method of same order is given for these systems. It is shown that the above mentioned scheme, not only preserves Hamiltonian but also uses the least CPU time compared with upto-date and optimized methods.

math.NA↗
arXiv2008

Upward shower rates at neutrino telescopes directly determine the neutrino flux

We show that the rate for upward showers from an isotropic cosmic neutrino flux at neutrino telescopes like IceCube is independent of the neutrino-nucleon cross section. For bins that span a relatively narrow range in energy, neither scaling the cross section, nor changing its power-law energy behavior affects the upward shower rate, which depends only on the flux. The neutrino flux can be completely known since its spectral shape can be determined by comparing the rates in neighboring bins. We also show that the downward shower rate varies linearly with cross section with a proportionality constant determined by the energy-dependence of the cross section, independent of the power-law behavior of the flux. The normalization and energy dependence of the cross section can be known by comparing the downward rates in neighboring bins.

hep-ph↗
arXiv2006

Cross section dependence of event rates at neutrino telescopes

We examine the dependence of event rates at neutrino telescopes on the neutrino-nucleon cross section for neutrinos with energy above 1 PeV, and contrast the results with those for cosmic ray experiments. Simple scaling of the Standard Model cross sections leaves the rates of upward events essentially unchanged. Details, such as detector depth and cross section inelasticity, can influence rates. Numerical estimates of upward shower, muon and tau event rates in the IceCube detector confirm these results.

hep-ph↗