299 citations · 868 across the 43 of their papers we have counts for
46 papers
Leptogenesis with a GeV-Scale Quasi-Dirac Neutrino
Stephen F. King, Soumen Kumar Manna, Rishav Roshan +1
We discuss leptogenesis in a model with a GeV-scale quasi-Dirac neutral lepton, comprising mainly sterile states, which is accessible to future experiments. In particular, we show…
Cosmological Consequences of a Highly Decoupled Right-handed Neutrino
Stephen F. King, Rishav Roshan, Sudipta Show
In the minimal type-I seesaw, one right-handed neutrino (RHN) can decouple from neutrino mass generation. Such a state is usually neglected, yet its feeble couplings make it long-l…
Minimal Scale-Invariant Dark Matter
Alexander Belyaev, Roman Pasechnik, Rishav Roshan +1
We study the minimal classically scale-invariant extension of the Standard Model, containing a single -stabilised real scalar singlet whose mass is not an independent…
Particle and Gravitational Wave Probes of Minimal Seesaw Neutrinos
Sanjoy Mandal, Rishav Roshan, Jose W. F. Valle
Observable gravitational waves (GWs) from first-order phase transitions (FOPTs) can coexist with distinct particle physics signatures. These include same-sign dilepton plus four~je…
Imprint of domain wall annihilation on induced gravitational waves
Rishav Roshan
Domain wall annihilation can leave a distinctive imprint on the induced gravitational wave spectrum. During annihilation, most of the domain wall energy transforms into the scalar…
Reheating Effects on Charged Lepton Yukawa Equilibration and Leptogenesis
Rishav Roshan
We show that accounting for a non-instantaneous reheating phase after inflation can significantly modify the charged lepton Yukawa equilibration temperature in the early Universe.…
Twin-peaked gravitational wave signals from a phase transition
Rishav Roshan, Indrajit Saha
We compute the gravitational wave spectrum from a phase transition associated with the spontaneous breaking of a symmetry. If the transition is second-orde…
Delayed Charged Lepton Yukawa Equilibration in Minimal Seesaw
Rishav Roshan, Sudipta Show
While most studies of the \textit{minimal type-I seesaw} neglect the heaviest decoupled right-handed neutrino, assuming negligible contributions to neutrino masses and leptogenesis…
Boomerang mechanism explaining the excess radio background
Bhupal Dev, Pasquale Di Bari, Ivan Martinez-Soler +1
We propose a boomerang mechanism for the explanation of the excess radio background detected by ARCADE 2. In an early stage of the Universe, at a temperature in the range $\sim…
Freeze-In Dark Matter and Leptogenesis: a SM route
Adeela Afzal, Rishav Roshan
We investigate the possibility of \emph{freeze-in} dark matter production and baryogenesis via leptogenesis in a SM model, which is an extension of the Standard Model, fe…
The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
Eleonora Di Valentino, Jackson Levi Said, Adam Riess +533
The standard model of cosmology has provided a good phenomenological description of a wide range of observations both at astrophysical and cosmological scales for several decades.…
Cosmological Consequences of Domain Walls Biased by Quantum Gravity
Yann Gouttenoire, Stephen F. King, Rishav Roshan +3
One of the simplest standard model extensions leading to a domain wall network is a real scalar with a symmetry spontaneously broken during universe evolution. Motivated…
Leptogenesis with Majoron Dark Matter
Stephen F. King, Soumen Kumar Manna, Rishav Roshan +1
We discuss a model of neutrino mass based on the type I seesaw mechanism embedded in a spontaneously broken global lepton number framework with a symmetry. We show that the r…
Gravitational Wave Production During Reheating: From the Inflaton to Primordial Black Holes
Mathieu Gross, Essodjolo Kpatcha, Yann Mambrini +2
We calculate the gravitational waves (GWs) produced by primordial black holes (PBHs) in the presence of the inflaton condensate in the early Universe. Combining the GW production f…
Testing leptogenesis and dark matter production during reheating with primordial gravitational waves
Basabendu Barman, Arindam Basu, Debasish Borah +2
We study the generation of baryon asymmetry as well as dark matter (DM) in an extended reheating period after the end of slow-roll inflation. Within the regime of perturbative rehe…
Relic neutrino decay: a solution to the excess radio background
Rishav Roshan
The detection of excess radio background detected by ARCADE 2 suggests the presence of new physics as there exists no clear astrophysical solution. We find that the radiative decay…
Observable gravitational waves and with global lepton number symmetry and dark matter
Debasish Borah, Nayan Das, Rishav Roshan
We study the possibility of testing a dark matter (DM) scenario embedded in a global lepton number symmetry via gravitational waves (GW) and cosmic microwave background (C…
Using gravitational waves to see the first second of the Universe
Rishav Roshan, Graham White
Gravitational waves are a unique probe of the early Universe, as the Universe is transparent to gravitational radiation right back to the end of inflation. In this article, we summ…
Leptogenesis, Dark Matter and Gravitational Waves from Discrete Symmetry Breaking
Subhaditya Bhattacharya, Niloy Mondal, Rishav Roshan +1
We analyse a model that connects the neutrino sector and the dark sector of the universe via a mediator , stabilised by a discrete symmetry that breaks to a remnant …
Relic neutrino decay solution to the excess radio background
P. S. Bhupal Dev, Pasquale Di Bari, Ivan Martínez-Soler +1
The excess radio background detected by ARCADE 2 represents a puzzle within the standard cosmological model. There is no clear viable astrophysical solution, and therefore, it migh…
Quantum Gravity Effects on Fermionic Dark Matter and Gravitational Waves
Stephen F. King, Rishav Roshan, Xin Wang +2
We explore the phenomenological consequences of breaking discrete global symmetries in quantum gravity (QG). We extend a previous scenario where discrete global symmetries are resp…
Quantum Gravity Effects on Dark Matter and Gravitational Waves
Stephen F. King, Rishav Roshan, Xin Wang +2
We explore how quantum gravity effects, manifested through the breaking of discrete symmetry responsible for both Dark Matter and Domain Walls, can have observational effects throu…
Baryon asymmetry from dark matter decay
Debasish Borah, Suruj Jyoti Das, Rishav Roshan
We propose a novel framework where baryon asymmetry can arise due to forbidden decay of dark matter (DM) enabled by finite temperature effects in the early universe. In order to im…
Imprint of PBH domination on gravitational waves generated by cosmic strings
Debasish Borah, Suruj Jyoti Das, Rishav Roshan +1
We study the effect of an ultra-light primordial black hole (PBH) dominated phase on the gravitational wave (GW) spectrum generated by a cosmic string (CS) network formed as a resu…