arXiv subjects

Ayan Chattaraj

Publications and source records attributed to Ayan Chattaraj.

4 recordsLinked to original sources

arXiv2026

Can Elastic Neutrino Scattering Account for the LZ230616 Event?

Recently, the LUX-ZEPLIN (LZ) Collaboration reported an isolated nuclear-recoil event at $248\pm 23_\mathrm{stat}\pm 23_\mathrm{syst}~\mathrm{keV_{nr}}$, in a region where the expected background is very small and conventional elastic dark matter (DM)-nucleus scattering cannot readily account for such a localized feature. We investigate whether LZ230616 could instead originate from coherent elastic neutrino-nucleus scattering (CE$\nu$NS). We consider neutrino-nucleus interactions within and beyond the Standard Model, together with exotic neutrino fluxes from DM annihilation ($\chi \chi \to \nu \bar{\nu}$) or decay ($\chi \to \nu \bar{\nu}$) into neutrino pairs and from primordial black hole (PBH) evaporation. We show that kinematic considerations, the accompanying low energy recoil spectrum, and existing constraints exclude a viable interpretation of LZ230616 in terms of elastic neutrino-nucleus scattering for all scenarios considered.

hep-ph↗

arXiv2026

Precision Tests of SM and new physics with the COHERENT Ge-mini and TEXONO data

A comprehensive numerical analysis of the latest germanium based CE$\nu$NS data from the COHERENT Ge-mini and TEXONO experiments has been conducted to test the Standard Model (SM) and search for new physics. By combining CE$\nu$NS and E$\nu$NS signals with a consistent treatment of detector effects and systematic uncertainties, we obtain a low energy determination of the weak mixing angle from COHERENT Ge-mini, in agreement with the SM prediction. We derive novel constraints on neutrino electromagnetic properties, including the magnetic moment, millicharge, charge radius, and anapole moment, with TEXONO providing particularly competitive bounds. Inclusion of E$\nu$NS, significantly improves the sensitivity to the neutrino millicharge by up to three orders of magnitude. We also investigated light scalar and vector mediators, finding striking complementarity between reactor and stopped pion sources across different mediator mass regimes. Finally, we put bounds on sterile neutral leptons production through transition dipole, scalar, and vector portals, probing masses from the sub MeV to tens of MeV scale. Our results demonstrate that current germanium based CE$\nu$NS experiments provide a powerful low energy laboratory for precision electroweak tests and complementary probes of a broad class of physics beyond the SM.

hep-ph↗

arXiv2025

Probing conventional and new physics at the ESS with coherent elastic neutrino-nucleus scattering

We explore the potential of the European Spallation Source (ESS) in probing physics within and beyond the Standard Model (SM), based on future measurements of coherent elastic neutrino-nucleus scattering (CE$ν$NS). We consider two SM physics cases, namely the weak mixing angle and the nuclear radius. Regarding physics beyond the SM, we focus on neutrino generalized interactions (NGIs) and on various aspects of sterile neutrino and sterile neutral lepton phenomenology. For this, we explore the violation of lepton unitarity, active-sterile oscillations as well as interesting upscattering channels such as the sterile dipole portal and the production of sterile neutral leptons via NGIs. The projected ESS sensitivities are estimated by performing a statistical analysis considering the various CE$ν$NS detectors and expected backgrounds. We find that the enhanced statistics achievable in view of the highly intense ESS neutrino beam, will offer a drastic improvement in the current constraints obtained from existing CE$ν$NS measurements. Finally, we discuss how the ESS has the potential to provide the leading CE$ν$NS-based constraints, complementing also further experimental probes and astrophysical observations.

hep-ph↗

arXiv2025

Probing Standard Model and Beyond with Reactor CE$ν$NS Data of CONUS+ experiment

We explore the potential of reactor antineutrino-induced Coherent Elastic Neutrino-Nucleus Scattering (CE$ν$NS) data from the CONUS+ experiment to investigate both the Standard Model (SM) and Beyond Standard Model (BSM) scenarios. Alongside CE$ν$NS, Elastic Neutrino-Electron Scattering (E$ν$ES) events are also included in our analysis, enabling more stringent constraints on new physics. Within the SM, we examine the weak mixing angle as a precision test of the electroweak sector. For BSM scenarios, we constrain the parameter space of light mediators arising from neutrino generalized interactions (NGI), while also setting limits on the electromagnetic properties of neutrinos, including their charge radius, millicharge, and magnetic moment.

hep-ph↗