arXiv subjects

Batool Imtiaz

Publications and source records attributed to Batool Imtiaz.

3 recordsLinked to original sources

arXiv2023

Testing the coupling of dark radiations in light of the Hubble tension

We are studying the effects of Self-Interacting dark radiation (SIdr) on the evolution of the universe. Our main focus is on the cosmic microwave background (CMB) and how SIdr could potentially help resolve the Hubble tension. We are looking into different scenarios by mixing SIdr with Free-Streaming dark radiation (FSdr) or not to determine whether SIdr can indeed contribute to solving the Hubble tension. We find that SIdr alone can increase the Hubble constant ($H_0$) to $70.1_{-1.6}^{+1.3}, \text{km/s/Mpc}$ with a value of $N_{\rm eff}=3.27_{-0.31}^{+0.23}$. However, including \lzy{FSdr} disfavors the existence of SIdr $\tilde N_{\rm si}\approx0.37$. Even though the Hubble constant is increased compared to the predicted value, it entails $N_{\rm eff}=3.52\pm0.25$. Finally, we implement the Fisher method for future experiments and a $7.64\sigma$ measurement of $\tilde N_{\rm si}$ will be obtained when combing data from Planck, AliCPT, and CMB-S4.

astro-ph.CO↗

arXiv2020

Updated constraints on superconducting cosmic strings from the astronomy of fast radio bursts

In this article we update constraints on superconducting cosmic strings (SCSs) in light of the recent observational developments of fast radio bursts (FRBs) astronomy. Assuming strings follow an exponential distribution characterized by current, we show that two parameters in our context, which are the characteristic tension ($G\mu$) and a parameter which describes the aforementioned exponential distribution ($I_c$), can be constrained by FRB experiments. Particularly, we investigate data sets from Parkes and ASKAP. We looked through a parameter space where $G\mu \sim [10^{-17}, 10^{-12}]$ and $I_c\sim [10^{-1}, 10^{2}]$ GeV, and found our results show that Parkes jointly with ASKAP can constrain the parameter space for SCSs.

astro-ph.HE↗

arXiv2018

Two-field cosmological phase transitions and gravitational waves in the singlet Majoron model

In the singlet Majoron model, we study cosmological phase transitions (PTs) and their resulting gravitational waves (GWs), in the two-field phase space, without freezing any of the field directions. We first calculate the effective potential, at one loop and at finite temperature, of the Standard Model Higgs doublet together with one extra Higgs singlet. We make use of the public available Python package CosmoTransitions to simulate the two-dimensional cosmological PTs and evaluate the gravitational waves generated by first-order PTs. With the full 2D simulation, we are able not only to confirm the PTs' properties previously discussed in the literature, but also we find new patterns, such as strong first-order PTs tunneling from a vacuum located on one axis to another vacuum located on the second axis. The two-field phase space analysis presents a richer panel of cosmological PT patterns compared to analysis with a single-field approximation. The PTGW amplitudes turn out to be out of the reach for the space-borne gravitational wave interferometers such as LISA, DECIGO, BBO, TAIJI and TianQin when constraints from colliders physics are taken into account.

hep-ph↗