arXiv subjects

Arman Esmaili

Publications and source records attributed to Arman Esmaili.

43 records · Page 3Linked to original sources

arXiv2012

KATRIN Sensitivity to Sterile Neutrino Mass in the Shadow of Lightest Neutrino Mass

The presence of light sterile neutrinos would strongly modify the energy spectrum of the Tritium β-electrons. We perform an analysis of the KATRIN experiment's sensitivity by scanning almost all the allowed region of neutrino mass-squared difference and mixing angles of the 3+1 scenario. We consider the effect of the unknown absolute mass scale of active neutrinos on the sensitivity of KATRIN to the sterile neutrino mass. We show that after 3 years of data-taking, the KATRIN experiment can be sensitive to mixing angles as small as sin^2 (2θ_s) ~ 10^-2. Particularly we show that for small mixing angles, sin^2 (2θ_s) < 0.1, the KATRIN experiment can gives the strongest limit on active-sterile mass-squared difference.

hep-ph↗

arXiv2011

A novel method to extract dark matter parameters from neutrino telescope data

Recently it has been shown that when the Dark Matter (DM) particles captured in the Sun directly annihilate into neutrino pairs, the oscillatory terms in the oscillation probability do not average to zero and can lead to a seasonal variation as the distance between the Sun and Earth changes in time. In this paper, we explore this feature as a novel method to extract information on the properties of dark matter. We show that by studying the variation of the flux over a few months, it would in principle be possible to derive the DM mass as well as new information on the flavor structure of the DM annihilation modes. In addition to analytic analysis, we present the results of our numerical calculations that take into account scattering and regeneration of neutrinos traversing the Sun.

hep-ph↗

arXiv2010

On the Oscillation of Neutrinos Produced by the Annihilation of Dark Matter inside the Sun

The annihilation of dark matter particles captured by the Sun can lead to a neutrino flux observable in neutrino detectors. Considering the fact that these dark matter particles are non-relativistic, if a pair of dark matter annihilates to a neutrino pair, the spectrum of neutrinos will be monochromatic. We show that in this case, even after averaging over production point inside the Sun, the oscillatory terms of the oscillation probability do not average to zero. This leads to interesting observable features in the annual variation of the number of muon track events. We show that smearing of the spectrum due to thermal distribution of dark matter inside the Sun is too small to wash out this variation. We point out the possibility of studying the initial flavor composition of neutrinos produced by the annihilation of dark matter particles via measuring the annual variation of the number of muon-track events in neutrino telescopes.

hep-ph↗

arXiv2009

Cosmic neutrinos at IceCube: $θ_{13}$, $δ$ and initial flavor composition

We discuss the prospect of extracting the values of the mixing parameters $δ$ and $θ_{13}$ through the detection of cosmic neutrinos in the planned and forthcoming neutrino telescopes. We take the ratio of the muon-track to shower-like events, R, as the realistic quantity that can be measured in the neutrino telescopes. We take into account several sources of uncertainties that enter the analysis. We then examine to what extent the deviation of the initial flavor composition from w_e:w_μ:w_τ=1:2:0 can be tested.

hep-ph↗

arXiv2009

Pseudo-Dirac Neutrino Scenario: Cosmic Neutrinos at Neutrino Telescopes

Within the "pseudo-Dirac" scenario for massive neutrinos the existence of sterile neutrinos which are almost degenerate in mass with the active ones is hypothesized. The presence of these sterile neutrinos can affect the flavor composition of cosmic neutrinos arriving at Earth after traveling large distances from astrophysical objects. We examine the prospects of neutrino telescopes such as IceCube to probe the very tiny mass squared differences 10^(-12) eV^2<Δm^2<10^(-19) eV^2, by analyzing the ratio of $μ$-track events to shower-like events. Considering various sources of uncertainties which enter this analysis, we examine the capability of neutrino telescopes to verify the validity of the pseudo-Dirac neutrino scenario and especially to discriminate it from the conventional scenario with no sterile neutrino. We also discuss the robustness of our results with respect to the uncertainties in the initial flavor ratio of neutrinos at the source.

hep-ph↗

arXiv2009

An Analysis of Cosmic Neutrinos: Flavor Composition at Source and Neutrino Mixing Parameters

We examine the feasibility of deriving neutrino mixing parameters $δ$ and $θ_{13}$ from the cosmic neutrino flavor composition under the assumption that the flavor ratios of the cosmic neutrinos at the source were $F_{ν_e}+F_{\barν_e}:F_{ν_μ}+F_{\barν_μ}: F_{ν_τ}+F_{\barν_τ}=1:2:0$. We analyze various uncertainties that enter the derivation of $δ$ and $θ_{13}$ from the ratio of the shower-like to $μ$-tracks events which is the only realistic source of information on the flavor composition at neutrino telescopes such as ICECUBE. We then examine to what extent the deviation of the initial flavor ratio from $1:2:0$ can be tested by measurement of this ratio at neutrino telescopes taking into account various sources of uncertainty.

hep-ph↗

arXiv2009

A new class of invariants in the lepton sector

We construct a new set of combinations from the mass matrices of the charged leptons and neutrinos that are invariant under basis transformation, hereafter {\it the} invariants. We use these invariants to study various symmetries and neutrino mass textures in a basis independent way. In particular, we show that by using these invariants the ansatz such as $μ-τ$ exchange and reflection symmetries, various texture zeros and flavor symmetries can be expressed in a general basis.

hep-ph↗