arXiv subjects

Basabendu Barman

Publications and source records attributed to Basabendu Barman.

At least 19 recordsLinked to original sources

arXiv2026

Status of light inflaton: from inflation to laboratory

We investigate the viability of the light inflaton scenario in light of the latest inflationary constraints from the Atacama Cosmology Telescope (ACT), together with bounds from collider and intensity-frontier experiments searching for a feebly coupled light scalar with a sub-GeV mass. Assuming a quartic inflaton potential, we identify the region of parameter space consistent with the ACT observations and derive constraints on the inflaton mass and inflaton-Higgs mixing using results from NA62, KOTO, BaBar, Belle, LHCb, MATHUSLA, FASER2, SHiP, and neutral meson oscillations. We also explore the prospects for dark matter production during reheating within this framework, while remaining consistent with the inflationary observables.

hep-ph↗

arXiv2026

Leptogenesis with sub-electroweak-scale reheating temperature

We study the generation of the baryon asymmetry of the Universe via leptogenesis during the post-inflationary reheating epoch, considering reheating temperatures below the temperature of sphaleron freeze-out. Within the framework of a monomial inflaton potential during reheating, we analyze three perturbative reheating scenarios in which the inflaton decays into (i) a pair of Standard Model (SM)-like bosons, (ii) a pair of SM-like fermions, or (iii) exclusively into a pair of heavy right-handed neutrinos, which eventually decays into the SM final states after briefly dominating the energy density of the Universe. For each case, we identify the regions of parameter space that successfully reproduce the observed baryon asymmetry consistently tracking the sphaleron interaction rate during reheating, while satisfying existing cosmological constraints. We also highlight the potential of future primordial gravitational wave observations to probe this class of scenarios.

hep-ph↗

arXiv2026

From WIMP to FIMP during reheating: collider vs non-collider probes for p-wave annihilation

By examining the transition from freeze-out to freeze-in dark matter (DM) production within the framework of perturbative reheating, where DM interacts with the visible sector through effective operators of dimension six, we have investigated how a broad range of new physics probes can reveal the nature of the pre-BBN Universe. Incorporating constraints from direct and indirect DM searches, invisible decay measurements, collider experiments, and gravitational wave observations, our analysis demonstrates that both current and forthcoming experimental sensitivities can serve as powerful tools for probing as well as constraining the post-inflationary era, together with new physics beyond the SM. Our analysis demonstrates that collider experiments at both the intensity and energy frontiers can impose strong bounds on derivative operators whose interactions are typically {\it p-wave suppressed}, and therefore only weakly constrained by astrophysical observations. In particular, these complementary searches can significantly restrict the allowed reheating temperature, DM mass and effective interaction scale required to reproduce the observed DM abundance for DM produced during the epoch of reheating.

hep-ph↗

arXiv2026

Imprints of Reheating Dynamics on Gravitational Waves from Phase Transitions

We investigate how perturbative reheating after inflation modifies the primordial gravitational wave (GW) spectrum generated by cosmological phase transitions. Within a specific inflationary setup, we show that the thermodynamic quantities that control the phase transition depend on the effective equation of state of the cosmological background, which is itself set by the form of the inflaton potential during reheating. Assuming reheating proceeds via perturbative dissipation of the inflaton condensate into boson or fermion pairs, we find that phase transitions taking place in this epoch generally produce GW signals that are systematically suppressed compared with the standard radiation-dominated scenario. We also identify characteristic spectral features that may arise in this case, which could serve as distinctive signatures of the modified expansion history during reheating.

astro-ph.CO↗

arXiv2026

Baryon-dark matter coincidence in Randall-Sundrum Model

Within the framework of the extra-dimensional Randall-Sundrum set-up, we investigate the freeze-in production of Standard Model (SM) gauge-singlet scalar, fermionic, and massive vector dark matter (DM). Assuming that both the DM and SM fields reside on the IR brane and interact solely through the graviton and radion portal, we demonstrate that the Planck-observed DM relic abundance can be achieved across a wide range of reheating temperatures, all while naturally addressing the hierarchy problem, satisfying constraints from collider and early Universe cosmology. We further show that the same set-up can accommodate TeV-scale leptogenesis capable of generating the observed baryon asymmetry of the Universe. Interestingly, we find that current graviton searches at the Large Hadron Collider (LHC) already impose strong constraints on the reheating temperature in this scenario, providing a complementarity between cosmological and collider probes.

hep-ph↗

arXiv2025

Constraining Gravitational Dark Matter with LHAASO and Fermi-LAT

We use diffuse Galactic high energy gamma ray data from LHAASO and Fermi-LAT to constrain gravitationally produced decaying dark matter (DM). Focusing on four benchmark candidates: a dark photon, a heavy right-handed neutrino (RHN), a pseudo-Nambu-Goldstone boson (pNGB), and a non-minimally coupled scalar we derive bounds on the DM mass and its couplings to the visible sector. For dark photons, RHNs, and pNGBs, the combined data constrain the relevant interaction strength to $\lesssim\mathcal{O}(10^{-30})$ for DM masses $\gtrsim\mathcal{O}$(TeV), while the non-minimally coupled scalar is limited to $\lesssim\mathcal{O}(10^{-10})$. Moreover, photon-dark photon oscillations yield strong constraints for massive dark photon beyond 10 GeV, closing a region of parameter space previously left unconstrained.

hep-ph↗

arXiv2025

New constraints on $Z^\prime$ from captured dark matter annihilation in astrophysical objects

Considering dark matter capture in astrophysical objects such as neutron stars and brown dwarfs, followed by their annihilation into two neutrino and four neutrino final states, we derive new constraints on the mass and coupling of a novel abelian gauge boson $Z^\prime$ arising from an anomaly-free $U(1)$ extension of the Standard Model. We further confront these astrophysical limits with complementary bounds from the Planck-observed relic abundance via the freeze-in mechanism, big bang nucleosynthesis (BBN), gravitational wave signatures from cosmic strings, and searches at energy and intensity frontier experiments.

hep-ph↗

arXiv2025

Indirect dark matter searches with neutrino telescopes via energetic cosmic showers

We explore the possibility that the high energy neutrino flux observed by terrestrial telescopes originates from dark matter (DM) annihilation. Specifically, we study a minimal, UV-complete $U(1)$ extension of the Standard Model with a Dirac DM candidate, whose annihilation into neutrinos proceeds exclusively through a $Z^\prime$ boson. By computing the annihilation cross section and comparing with the observed flux, we derive bounds on the model parameters. Additional constraints are obtained within the freeze-in framework, where the observed relic abundance is reproduced, leading to the strongest bounds. Considering cosmic string vibrations as a source of gravitational waves, we further constrain the vacuum expectation value of the $U(1)$ breaking. All results are contrasted with perturbativity limits and existing constraints from low- and high-energy experiments.

hep-ph↗

arXiv2025

Implications of DESI for Dark Matter & Cosmic Birefringence

We explore an interacting dark matter (DM)-dark energy (DE) framework that naturally yields an effective dynamical DE equation of state crossing the phantom barrier at early times, as indicated by recent DESI data, while also accounting for the observed isotropic rotation of the cosmic microwave background (CMB) linear polarization. Within this unified framework, we also explain the DM relic abundance without introducing additional fields or couplings. Depending on the DE potential, we identify two viable scenarios: a superheavy freeze-in DM requiring a high reheating temperature, or a strongly interacting dark sector with a GeV-TeV scale thermal DM candidate.

hep-ph↗

arXiv2025

Light PIDM in Warped Extra Dimensions

Traditional Planckian Interacting Dark Matter (PIDM), which interacts exclusively through gravity, typically requires heavy DM candidates (with mass $10^3-10^{15}$ GeV) and very high reheating temperature ($T_{\rm rh}\gtrsim 10^{15}$ GeV). In this article, we explore a novel realization of PIDM in warped five-dimensions, consisting of an "Ultra Violet"$-$"Dark"$-$"Infra Red" (UV-DB-IR) brane setup, where the DM can be a Dark brane composite light state with mass 1 MeV $-$ 1 TeV. The DM sector is assumed to interact solely via gravity in five-dimensions. After orbifolding and performing a Kaluza-Klein (KK) decomposition, the DM is assumed to be localized onto the DB, which is positioned in the extra-dimension such that the DM interacts with both the massless graviton and its massive KK excitations, with suppressed couplings to remain consistent with the ethos of the PIDM framework. The light (heavy) Standard Model matter is assumed to be localized near UV (IR) branes for the geometric Froggatt-Nielsen mechanism, while their KK modes are localized close to the IR brane. We show that this construction allows for a viable and efficient freeze-in production mechanism for light composite PIDM, consistent with TeV-scale reheating temperature.

hep-ph↗

arXiv2025

Freeze-in production of scalaron dark matter in $f(R)$ gravity

We demonstrate that the scalaron, a scalar degree of freedom, emerging from the $f(R)$ theory of gravity, can account for the observed dark matter (DM) abundance if its mass is around the MeV scale, to ensure its cosmological stability. Focusing on two well-known $f(R)$ gravity models, we systematically show that if scalaron production proceeds via the freeze-in mechanism, the right relic abundance is satisfied over a very narrow window of reheating temperature $10^{14}\lesssim T_{\rm rh}\lesssim 10^{16}$ GeV. We delineate the viable parameter space of the $f(R)$ models consistent with the observed DM abundance, and highlight relevant experimental constraints from searches targeting DM decay signatures.

hep-ph↗

arXiv2025

What KM3-230213A events may tell us about the neutrino mass and dark matter

Within the framework of general $U(1)$ scenario, we demonstrate that the ultra high energy neutrinos recently detected by KM3NeT could originate from a decaying right handed neutrino dark matter (DM), with a mass of 440 PeV. Considering DM production via freeze-in, we delineate the parameter space that satisfies the observed relic abundance and also lies within the reach of multiple gravitational wave detectors. Our study provides a testable new physics scenario, enabled by multi-messenger astronomy.

hep-ph↗

arXiv2025

Two or three things particle physicists (mis)understand about (pre)heating

The transition from the end of inflation to a hot, thermal Universe, commonly referred to as (re)heating, is a critical yet often misunderstood phase in early Universe cosmology. This short review aims to provide a comprehensive, conceptually clear, and accessible introduction to the physics of (re)heating, tailored to the particle physics community. We critically examine the standard Boltzmann approach, emphasizing its limitations in capturing the intrinsically non-perturbative and non-linear dynamics that dominate the early stages of energy transfer. These include explosive particle production, inflaton fragmentation, turbulence, and thermalization; phenomena often overlooked in perturbative treatments. We survey a wide range of theoretical tools, from Boltzmann equations to lattice simulations, clarifying when each is applicable and highlighting scenarios where analytic control is still feasible. Special attention is given to model-dependent features such as (pre)heating, the role of fermions, gravitational couplings, and the impact of multifield dynamics. We also discuss exceptional cases, including Starobinsky-like models and instant (pre)heating, where (re)heating proceeds through analytically tractable channels without requiring full non-linear simulations. Ultimately, this review serves both as a practical guide and a cautionary tale, advocating for a more nuanced and physically accurate understanding of this pivotal epoch within the particle physics community.

hep-ph↗

arXiv2025

Hunting for heavy $Z^\prime$ with IceCube neutrinos and gravitational waves

In the minimal gauged B-L extension of the Standard Model, we demonstrate that PeV-scale dark matter (DM) and the baryon asymmetry of the Universe (BAU) can be simultaneously explained through the three right-handed neutrinos (RHNs) present in the theory. The DM candidate undergoes decay into light neutrinos, providing an explanation for the observed IceCube events, while the other two RHNs generate the BAU via leptogenesis. The breaking of gauge symmetry gives rise to detectable gravitational waves (GWs) from decaying cosmic strings (CS), making this framework testable at several future GW detectors-despite being beyond the reach of conventional collider experiments due to the extremely weak coupling. The symmetry-breaking scale establishes a connection between particle masses, couplings, and the GW spectrum, offering a unified and predictive scenario.

hep-ph↗

arXiv2024

Asymmetries from a charged memory-burdened PBH

We explore a purely gravitational origin of observed baryon asymmetry and dark matter (DM) abundance from asymmetric Hawking radiation of light primordial black holes (PBH) in presence of a non-zero chemical potential, originating from the space-time curvature. Considering the PBHs are described by a Reissner-Nordstr\"{o}m metric, and are produced in a radiation dominated Universe, we show, it is possible to simultaneously explain the matter-antimatter asymmetry along with right DM abundance satisfying bounds from big bang nucleosynthesis, cosmic microwave background and gravitational wave energy density due to PBH density fluctuation. We also obtain the parameter space beyond the semiclassical approximation, taking into account the quantum effects on charged PBH dynamics due to memory burden.

hep-ph↗

arXiv2024

Testing leptogenesis and dark matter production during reheating with primordial gravitational waves

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 reheating, we consider different monomial potential of the inflaton field during reheating era. The inflaton condensate reheats the Universe by decaying into the Standard Model (SM) bath either via fermionic or bosonic decay modes. Assuming the leptogenesis route to baryogenesis in a canonical seesaw framework, we consider both the radiation bath and perturbative inflaton decay to produce such RHNs during the period of reheating when the maximum temperature of the SM bath is well above the reheating temperature. The DM, assumed to be a SM gauge singlet field, also gets produced from the bath during the reheating period via UV freeze-in. In addition to obtaining different parameter space for such non-thermal leptogenesis and DM for both bosonic and fermionic reheating modes and the type of monomial potential, we discuss the possibility of probing such scenarios via spectral shape of primordial gravitational waves.

hep-ph↗

arXiv2024

Lepton collider as a window to reheating via freezing in dark matter detection. Part II

Dark matter (DM) genesis via Ultraviolet (UV) freeze-in embeds the seed of reheating temperature and dynamics in its relic density. Thus, discovery of such a DM candidate can possibly open the window for post-inflationary dynamics. However, there are several challenges in this exercise, as freezing-in DM possesses feeble interaction with the visible sector and therefore very low production cross-section at the collider. We show that mono-photon (and dilepton) signal at the ILC, arising from DM effective operators connected to the SM field strength tensors, can still warrant a signal discovery. We study both the scalar and fermionic DM production during reheating via UV freeze-in, when the inflaton oscillates at the bottom of a general monomial potential. Interestingly, we see, right DM abundance can be achieved only in the case of bosonic reheating scenario, satisfying bounds from big bang nucleosynthesis (BBN). This provides a unique correlation between collider signal and the post-inflationary dynamics of the Universe within single-field inflationary models.

hep-ph↗

arXiv2024

Is leptogenesis during gravitational reheating flavourful?

We examine the impact of charged lepton Yukawa equilibration on leptogenesis during gravitational reheating. During the post-inflationary era, the inflaton field is assumed to oscillate around the minimum of a monomial potential, leading to the gravitational production of Standard Model (SM) particles, constituting the radiation bath. The heavy right-handed neutrinos (RHN), responsible for generating baryon asymmetry via leptogenesis, are also produced through graviton-mediated scattering of the homogeneous inflaton field and thermal bath, as well as from the the inverse decay of the bath particles. By considering both minimal and non-minimal gravitational contributions to SM, we demonstrate that flavour effects can be safely neglected in the minimal reheating scenario. However, with large non-minimal coupling, these effects may become important, depending on the choice of the RHN mass. We identify the corresponding viable parameter space that satisfies the observed baryon asymmetry in each case.

hep-ph↗