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Indra Kumar Banerjee

Publications and source records attributed to Indra Kumar Banerjee.

17 recordsLinked to original sources
arXiv2026

Enlightening dark moments of neutrino with superradiance

Neutrinos can acquire electromagnetic moments either within the Standard Model through higher order radiative corrections or within the domain of new physics. In this study we focus on probing these beyond the standard model neutrino moments through quenched superradiance of black holes where fermionic pairs can be produced from the superradiant bosonic cloud. We consider the production of dark photons from black hole superradiance and quenching occurs through the production of neutrino-antineutrino pairs from the dark photons. The efficiency of the pair production depends on the effective coupling between the dark photons and neutrinos, i.e., the dark electromagnetic moments. We also discuss bounds on primordial black hole abundance from neutrino background arising from this quenched superradiance mechanism.

hep-ph↗
arXiv2026

Primordial Black Holes from Slow Phase Transitions with Delayed Reheating: A Peak-Theory Approach

We study the possibility of significant PBH production from a slow first-order phase transition with delayed reheating. Since delayed reheating results in an early matter-dominated phase between percolation and reheating, we developed a peak-theoretic approach to PBH formation during this phase based on the non-Gaussian distribution of overdensity arising from the transition. To obtain the collapse probability, we performed large-scale Monte Carlo simulations and employed the hoop-conjecture criterion. We include tidal-torque terms to investigate the initial spin of the PBHs and find that the average spin parameter is $\mathcal{O}(10^{-3})$. Furthermore, we obtain an emergent overdensity threshold for collapse that depends on the phase transition properties and reheating efficiency. We find that the resulting PBH abundance is extremely sensitive to the reheating efficiency, with order-unity changes in efficiency leading to variations of many orders of magnitude in the collapse fraction. We identify regions of parameter space where the resulting PBHs can account for the entirety of the dark matter abundance. Finally, we also constrain the phase transition and reheating properties from current data on (non-)observations of PBHs.

hep-ph↗
arXiv2025

Radiative symmetry breaking in a gauged Zee-Babu model and its gravitational wave imprints

We construct a classically scale invariant version of the Zee-Babu model governed by an $U(1)_{B-L}$ gauge symmetry wherein three right handed neutrinos with identical gauge charges are present. A $\mathbb{Z}_2$ symmetry is additionally imposed such that the lightest right handed neutrino becomes a dark matter candidate. A spontaneous breakdown of the $U(1)_{B-L}$ gauge group is triggered radiatively through renormalisation group effects and the dimensionful parameters thus emerging are proportional to the corresponding breaking scale $v_{BL}$. We demonstrate in this study how the same $v_{BL}$ controls the dynamics of neutrino mass generation, lepton flavour violation and dark matter phenomenology. It is revealed that the scenario can simultaneously accommodate the observed neutrino masses and mixings, an appropriately low lepton flavour violation and the observed dark matter relic density for 10 TeV $\lesssim v_{BL} \lesssim$ 55 TeV. In addition, the very radiative nature of the set-up signals a strong first order phase transition in the presence of a non-zero temperature. Stochastic gravitational waves stemming from this phase transition are within the reach of detectors such as LISA and BBO. The scenario therefore emerges as a concrete platform to test classical scale invariance that is tied to neutrino masses and dark matter, through gravitational waves.

hep-ph↗
arXiv2025

Superradiant and dynamical spin-down of neutron stars with gravitational wave implications

Neutron stars such as pulsars and magnetars lose angular momentum primarily through electromagnetic dipole radiation, gravitational waves, $r$-mode oscillation, and also affected by fallback accretion processes. However, anomalous spin variations, particularly sudden enhanced spin-down rates, indicate additional spin-down mechanisms. We propose superradiant spin-down as a potential explanation for these events. By modelling the interplay between conventional and superradiant spin-down channels, we evaluate their impact on neutron star rotational evolution. We also discuss gravitational-wave emission produced by quadrupole deformation, $r$-mode oscillations, and axion-induced bosonic clouds around an isolated neutron star, highlighting their potential as distinct multimessenger probes in upcoming detectors.

astro-ph.HE↗
arXiv2025

Bounds on Exotic Couplings from a New $\nu$-Background

We propose a hitherto unexplored neutrino background emerging from the mechanism of quenched superradiance of rotating primordial black holes. The quenching of the phenomenon happens through fermionic production, in our case neutrino production, from the boson cloud formed due to superradiance. The couplings involved in these interactions are bounded from above through several studies. In this work we put lower bounds on such scalar and vector couplings.

hep-ph↗
arXiv2025

Neutrino Decoherence via Modified Dispersion

We study in detail the effect of quantum decoherence in neutrino oscillations. We adopt a phenomenological approach that allows us to parametrize the energy dependence of the decoherence effects resulting from the modification of the neutrino dispersion relation. Using the open quantum system framework we derive decoherence parameters, which are usually connected to quantum gravitational effects. Furthermore, we study the sensitivity of decoherence on high-energy astrophysical neutrinos among all possible initial source compositions. We find that variation in the flux composition at neutrino telescopes can be a good probe to test such effects. Additionally, we show that a simple extension with heavy sterile neutrino decoherence produces verifiable signatures.

hep-ph↗
arXiv2025

Primordial Black Holes and Gravitational Waves in Extensions of the Standard Model

We investigate the phenomenology of a Standard Model extension incorporating an inert scalar doublet and a gauged $U(1)_{B-L}$ symmetry. Our analysis reveals regions of the parameter space that support strong first-order phase transitions, including cases featuring two successive transitions. Each transition can generate a stochastic gravitational wave background within the sensitivity reach of upcoming experiments. Remarkably, the high-scale transition may also produce primordial black holes with appreciable abundance.

hep-ph↗
arXiv2024

Primordial Black Holes (as Dark Matter) from the Supercooled Phase Transitions with Radiative Symmetry Breaking

We study in detail the production of primordial black holes (PBHs), as well as their mass and initial spin, due to the phase transitions corresponding to radiative symmetry breaking (RSB) and featuring a large supercooling. The latter property allows us to use a model-independent approach. In this context, we demonstrate that the decay rate of the false vacuum grows exponentially with time to a high degree of accuracy, justifying a time dependence commonly assumed in the literature. Our study provides ready-to-use results for determining the abundance, mass and initial spin of PBHs generated in a generic RSB model with large supercooling. We find that PBHs are generically produced in a broad region of the model-independent parameter space. As an application, we identify the subregion that may explain recently reported microlensing anomalies. Additionally, we show that a simple Standard-Model extension, with right-handed neutrinos and gauged $B-L$ featuring RSB, may explain an anomaly of this sort in a region of its parameter space.

hep-ph↗
arXiv2024

Spin of Primordial Black Holes from Broad Power Spectrum: Radiation Dominated Universe

We perform a study to obtain the initial spin or the nondimensional Kerr parameter $a_{*}$ of primordial black holes (PBHs) created during the radiation dominated phase of the universe from not only nearly monochromatic but also broad curvature power spectra. Motivated by inflation and first-order phase transitions, we consider a power law shape for the curvature perturbation. Although we can naturally neglect the contribution from the length scales smaller than the scale of interest, that from the larger scales may potentially be significant for a broad power spectrum, for which the spin is sensitive to the width of the power spectrum. So, we introduce a width parameter $r_{k}$, the ratio of the largest scale to the length of interest. We find that the root mean square of $a_{*}$ is largest for PBHs created from locally nearly scale invariant curvature power spectra with $r_{k} \sim 3.5$. The upper limit is $\sim 1\times 10^{-4}$ for $M=10^{17}-10^{23}$ g, $\sim 1.7\times 10^{-4}$ for $M=1-100 M_{\odot}$ and $\sim 2.5\times 10^{-3}$ even for an incredibly large mass of $M=10^{50}$ g.

gr-qc↗
arXiv2024

Multi-messenger Astronomy with Quenched Superradiance

We propose a novel method to study the ultra-light bosons, where compact rotating objects undergo the phenomenon of quenched superradiance to create gravitational waves and neutrino flux signals. The neutrino flux results from appropriate coupling between the ultra-light bosons and the neutrinos. We consider a heavy sterile neutrino generation from ultralight scalar, which later results in active neutrino flux through neutrino oscillations, whereas we consider active neutrino generation directly from the vector bosons. We study the intertwining of gravitational waves and neutrino flux signals produced from a single source and elaborate if and when the signals can be detected in existing and upcoming experiments in a direct manner.

hep-ph↗
arXiv2024

Primordial Black Holes and Gravitational Waves in the $U(1)_{B-L}$ Extended Inert Doublet Model: A First-Order Phase Transition Perspective

We conduct an analysis of a $U(1)_{B-L}$ extended inert doublet model and obtained the parameter space allowing strong first order phase transitions. We show that a large part of the parameter space can cause double first-order phase transitions. Whereas both of these phase transitions can generate a detectable stochastic gravitational wave background, one of them can create primordial black holes with appreciable abundance. The primordial black holes generated at the high scale transition can account for the dark matter maintaining the correct relic abundance. We also show specific benchmark cases and their consequences from the aspect of primordial black holes and gravitational waves.

hep-ph↗
arXiv2024

Gravitational Wave Probe of Primordial Black Hole Origin via Superradiance

In this article we have used stochastic gravitational wave background as a unique probe to gain insight regarding the creation mechanism of primordial black holes. We have considered the cumulative gravitational wave background which consists of the primary part coming from the creation mechanism of the primordial black holes and the secondary part coming from the different mechanisms the primordial black holes go through. We have shown that in the presence of light or ultra light scalar bosons, superradiant instability generates the secondary part of the gravitational wave background which is the most detectable. In order to show the unique features of the cumulative background, we have considered the delayed vacuum decay during a first order phase transition as the origin of primordial black holes. We have shown the dependence of the features of the cumulative background, such as the mass of the relevant light scalars, peak frequencies, etc. on the transition parameters. We have also generated the cumulative background for a few benchmark cases to further illustrate our claim.

gr-qc↗
arXiv2024

PTOLEMY's test of generalized neutrino interactions: unveiling challenges and constraints

Unanswered questions surrounding neutrinos have motivated investigations into physics beyond the standard model (SM) of particle physics. In particular, generalized neutrino interactions (GNI) provide a broader framework for studying these effects compared to the commonly studied non-standard neutrino interactions. These interactions are described by higher dimensional operators while maintaining the gauge symmetries of the SM. Furthermore, the cosmic neutrino background, a predicted component of the SM and standard cosmology, has yet to be directly detected. To shed light on this elusive phenomenon, we conduct a comprehensive analysis of the relevant GNI, specifically focusing on their implications for the proposed cosmic neutrino detector PTOLEMY. We make an attempt to see the capabilities and the limitations of PTOLEMY in sensing GNI while remaining optimistic regarding PTOLEMY's experimental resolution. These interactions play a significant role in modifying the electron spectrum resulting from the capture of cosmic neutrinos on radioactive tritium. This work also explores how the presence of these interactions influences the differential electron spectrum, taking into account factors such as finite experimental resolution, the mass of the lightest neutrino eigenstate, the strength of the interactions, and the ordering of neutrino mass.

hep-ph↗
arXiv2023

Spinning Primordial Black Holes from First Order Phase Transition

We conduct a novel study to obtain the initial spin of the primordial black holes created during a first-order phase transition due to delayed false vacuum decay. Remaining within the parameter space consistent with observational bounds, we express the abundance and the initial spin of the primordial black holes as functions of the phase transition parameters. The abundance of the primordial black holes is extremely sensitive to the phase transition parameters. We also find that the initial spin weakly depends on all parameters except the transition temperature.

gr-qc↗
arXiv2023

Probing the Origin of Primordial Black Holes through Novel Gravitational Wave Spectrum

In this article we investigate the cumulative stochastic gravitational wave spectra as a tool to gain insight on the creation mechanism of primordial black holes. We consider gravitational waves from the production mechanism of primordial black holes and from the gravitational interactions of those primordial black holes among themselves and other astrophysical black holes. We specifically focus on asynchronous bubble nucleation during a first order phase transition as the creation mechanism. We have used two benchmark phase transitions through which the primordial black holes and the primary gravitational wave spectra have been generated. We have considered binary systems and close hyperbolic interactions of primordial black holes with other primordial and astrophysical black holes as the source of the secondary part of the spectra. We have shown that this unique cumulative spectra have features which directly and indirectly depend on the specifics of the production mechanism.

gr-qc↗
arXiv2023

Neutrino Decoherence from Generalised Uncertainty

Quantum gravity models predict a minimal measurable length which gives rise to a modification in the uncertainty principle. One of the simplest manifestations of these generalised uncertainty principles is the linear quadratic generalised uncertainty principle which leads to a modified Heisenberg algebra. This can alter the usual von-Neumann evolution of density matrix to a Lindblad-type equation. We show how this can give rise to a decoherence in neutrino propagation in vacuum. The decoherence effects due to the linear quadratic generalised uncertainty principle are extremely minimal and is unlikely to be detectable in the existing or upcoming experimental facilities for any of the natural sources of neutrinos. We also show that, in principle, there can be other variants of generalised uncertainty principle which predicts verifiable decoherence effects for the cosmic neutrino background.

hep-ph↗