arXiv subjects

S. Tizchang

Publications and source records attributed to S. Tizchang.

6 recordsLinked to original sources

arXiv2021

Searching for lepton flavor violating interactions at future electron-positron colliders

Lepton flavor violating interactions are absent in the standard model but are expected in various beyond standard models. In this work, the potential of the future circular electron-positron collider to probe the four fermion lepton flavor couplings via the $e^{+}e^{-}\rightarrow e^{\pm}τ^{\mp}$ process is revisited by means of an effective field theory approach. We provide constraints at $95\%$ CL on the dimension-six Wilson coefficients including major sources of background processes and considering realistic detector effects at four expected operation energies $\sqrt{s}=157.5$, $162.5$, $240$ and $365$ GeV according to their corresponding integrated luminosities. We demonstrate that statistical combination of the results from four center-of-mass energies improves the sensitivity to the LFV couplings significantly. We compare the results with the prospects from Belle II with $50~ ab^{-1}$ and other studies at electron-positron colliders.

hep-ph↗

arXiv2020

Circular polarization of cosmic photons due to their interactions with Sterile neutrino dark matter

In this paper, we explore the possibility of the polarization conversion of a wide energy range of cosmic photons to the circular polarization through their interactions with right handed Sterile neutrinos as a candidate for dark matter. By considering the Sterile neutrino in the seesaw mechanism framework and right-handed current model, we examine the Faraday conversion $Δϕ_\text{\tiny{FC}}$ of gamma ray burst (GRB) photons at both the prompt and afterglow emission levels as well as the radio photons emitted from our galaxy and extra-galactic sources interacting with the Sterile neutrinos. Consequently, for the Sterile neutrino with mixing angle $θ^2\lesssim 10^{-2}$ motivated by models with a hidden sector coupled to the sterile neutrino, the Faraday conversion can be estimated as $Δϕ_\text{\tiny{FC}}\lesssim 10^{-3}-10^{-18}$ rad for GRB, $Δϕ_\text{\tiny{FC}}\lesssim 10^{-6}-10^{-11}$ rad for radio emission source from our galaxy and $Δϕ_\text{\tiny{FC}}\lesssim 10^{-6}-10^{-15}$ rad for extra-galactic sources. We also examine the V-mode power spectrum $C_{Vl}$ of the cosmic microwave background (CMB) at the last scattering surface. We show that the circular polarization power spectrum at the leading order is proportional to the linear polarization power spectrum $C_{pl}$ and the mixing angle where for $θ^2\lesssim 10^{-2}$ leads to $C_{Vl}\lesssim 0.01$ Nano-Kelvin squared.

hep-ph↗

arXiv2016

Generation of circular polarization of gamma ray bursts

The generation of the circular polarization of Gamma Ray Burst (GRB) photons is discussed in this paper via their interactions with astroparticles in the presence or absence of background fields such as magnetic fields and non-commutative space time geometry. Solving quantum Boltzmann equation for GRB-photons as a photon ensemble, we discuss the generation of circular polarization (as Faraday conversion phase shift $Δϕ_{FC}$) of GRBs in the following cases: (i) intermediate interactions, i.e. the Compton scattering of GRBs in the galaxy cluster magnetic field and in the presence of non-commutative space time geometry, as well as the scattering of GRBs in cosmic neutrino background (CNB), and in cosmic microwave background (CMB); (ii) interactions with particles and fields in shock wave, i.e. the Compton scattering of GRBs with accelerated charged particles in the presence of magnetic fields. We found that (i) after shock wave crossing, the most contribution of $Δϕ_{FC}$ for energetic GRBs (in order GeV and larger) comes from GRB-CMB interactions, however for low energy GRBs the contributions of the Compton scattering of GRBs in the galaxy cluster magnetic field dominate; (ii) in shock wave crossing, the magnetic filed has significant effects on converting GRB's linear polarization to circular one, this effect can be used to better understanding magnetic profile in shock wave. The main aim of this work is a emphasis that the studying and measuring the circular polarization of GRBs are helpful for better understanding of physics and mechanism of the generation of GRBs and their interactions before reaching us.

astro-ph.HE↗

arXiv2016

Using an intense laser beam in interaction with muon/electron beam to probe the Noncommutative QED

It is known that the linearly polarized photons can partly transform to circularly polarized ones via forward Compton scattering in a background such as the external magnetic field or noncommutative space time. Based on this fact we explore the effects of the NC-background on the scattering of a linearly polarized laser beam from an intense beam of charged leptons. We show that for a muon/electron beam flux $\bar\varepsilon_{μ,e}\sim 10^{12}/10^{10}\,{\rm TeV}\,{\rm cm}^{-2}\,{\rm sec}^{-1}$ and a linearly polarized laser beam with energy $k^0\sim $1 eV and average power $\bar{P}_{\rm laser}\simeq$1 MW, the generation rate of circularly polarized photons is about $R_{_V} \sim 10^4/{\rm sec}$ for Noncommutative energy scale $Λ_{\tiny{NC}}\sim 10$TeV. This is fairly large and can grow for more intense beams in near future.

hep-ph↗

arXiv2016

Cosmic microwave background polarization in Noncommutative space-time

In the standard model of cosmology (SMC) the B-mode polarization of the CMB can be explained by the gravitational effects in the inflation epoch. However, this is not the only way to explain the B-mode polarization for the CMB. It can be shown that the Compton scattering in presence of a background besides generating a circularly polarized microwave, can leads to a B-mode polarization for the CMB. Here we consider the non-commutative (NC) space time as a background to explore the CMB polarization at the last scattering surface. We obtain the B-mode spectrum of the CMB radiation by scalar perturbation of metric via a correction on the Compton scattering in NC-space-time in terms of the circular polarization power spectrum and the non-commutative energy scale. It can be shown that even for the NC-scale as large as $10TeV$ the NC-effects on the CMB polarization and the r-parameter is significant. We show that the V-mode power spectrum can be obtained in terms of linearly polarized power spectrum in the range Micro to Nano-Kelvin squared for the NC-scale about $1TeV$ to $10TeV$, respectively.

hep-ph↗

arXiv2014

Higgs Couplings in NonCommutative Standard Model

We consider the Higgs and Yukawa parts of the Non-Commutative Standard Model (NCSM). We explore the NC-action to give all Feynman rules for couplings of the Higgs boson to electro-weak gauge fields and fermions.

hep-ph↗