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Federica Pompa

Publications and source records attributed to Federica Pompa.

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Invisible decay of solar neutrinos at dark matter experiments

The combination of the long baseline and characteristic energies of solar neutrinos offers an ideal framework to probe invisible neutrino decay. In this work we present the first constraint on invisible solar-neutrino decay using coherent elastic neutrino-nucleus scattering, recently observed in dark matter direct detection experiments. Through a combined analysis of nuclear-recoil data from XENONnT, PandaX-4T, and LUX-ZEPLIN, we constrain the lifetime of the neutrino mass state $\nu_{2}$, obtaining a bound already comparable in strength to that from the Sudbury Neutrino Observatory. We further evaluate the sensitivity that could be reached by a future xenon-based dark matter detector. For this projection, we extend the analysis to electronic-recoil data, estimating the impact of detecting lower-energy solar neutrinos from the $pp$-chain via elastic scattering off electrons. This channel would allow us to place strong constraints on the lifetimes of both the $\nu_{1}$ and $\nu_{2}$ mass eigenstates. Our results show that, with nominal future exposures, nuclear-recoil data would improve the current bound by about one order of magnitude, while electronic-recoil data would open a new detection channel for low-energy solar neutrinos, surpassing existing dedicated solar-neutrino bounds by 1 to 2 orders of magnitude.

hep-ph

Testing light and heavy vector mediators with solar CE$\nu$NS measurements

The recent observation of coherent elastic neutrino-nucleus scattering from solar $^8$B neutrinos in dark matter direct detection experiments has inaugurated the \emph{neutrino fog} era, highlighting the extended potential of these experiments as precision neutrino observatories. Recent measurements by the XENONnT, PandaX-4T, and LUX-ZEPLIN experiments provide new opportunities to test Standard Model predictions and to probe physics beyond it, in complementarity with dedicated neutrino facilities. We perform a combined analysis of nuclear recoil data from these three facilities to extract information on the solar $^8$B neutrino flux normalization and on the weak mixing angle at low-momentum transfer. We further investigate the impact of new vector interactions on the solar neutrino event rate, deriving constraints on nonstandard neutrino interactions and on scenarios with light vector mediators. Our results demonstrate that dark matter detectors are rapidly becoming complementary to terrestrial neutrino experiments in probing neutrino interactions, and already set competitive bounds on both light and heavy vector mediators.

hep-ph

Shedding light on dark matter spikes through refractive neutrino masses

The origin of neutrino mass remains an open question in particle physics. One intriguing possibility is that neutrinos are massless in vacuum but acquire an effective refractive mass through interactions with ultralight dark matter during propagation. We investigate the capability of the upcoming Deep Underground Neutrino Experiment (DUNE) to probe such refractive masses using the time-of-flight delays of neutrinos from a galactic core-collapse supernova. Our analysis shows that DUNE can set competitive bounds on the refractive neutrino mass, with sensitivity significantly enhanced if neutrinos traverse a dark matter density spike near the Galactic Center. In particular, we quantify how the presence of a spike modifies the projected limits, demonstrating that supernova neutrino observations at DUNE provide a powerful and novel avenue to test both the nature of neutrino masses and the distribution of dark matter in the innermost regions of the Milky Way.

hep-ph

Neutrino Theory in the Precision Era

This document summarises discussions on future directions in theoretical neutrino physics, which are the outcome of a neutrino theory workshop held at CERN in February 2025. The starting point is the realisation that neutrino physics offers unique opportunities to address some of the most fundamental questions in physics. This motivates a vigorous experimental programme which the theory community fully supports. \textbf{A strong effort in theoretical neutrino physics is paramount to optimally take advantage of upcoming neutrino experiments and to explore the synergies with other areas of particle, astroparticle, and nuclear physics, as well as cosmology.} Progress on the theory side has the potential to significantly boost the physics reach of experiments, as well as go well beyond their original scope. Strong collaboration between theory and experiment is essential in the precision era. To foster such collaboration, \textbf{we propose to establish a CERN Neutrino Physics Centre.} Taking inspiration from the highly successful LHC Physics Center at Fermilab, the CERN Neutrino Physics Centre would be the European hub of the neutrino community, covering experimental and theoretical activities.

hep-ph

How much do neutrinos live and weigh?

The next-generation water Cherenkov Hyper-Kamiokande detector will be able to detect thousands of neutrino events from a galactic Supernova explosion via Inverse Beta Decay processes followed by neutron capture on Gadolinium. This superb statistics provides a unique window to set bounds on neutrino properties, as its mass and lifetime. We shall explore the capabilities of such a future detector, constraining the former two properties via the time delay and the flux suppression induced in the Supernovae neutrino time and energy spectra. Special attention will be devoted to the statistically sub-dominant elastic scattering induced events, normally neglected, which can substantially improve the neutrino mass bound via time delays. When allowing for a invisible decaying scenario, the $95\%~$C.L. lower bound on $τ/m$ is almost one order of magnitude better than the one found with SN1987A neutrino events. Simultaneous limits can be set on both $m_ν$ and $τ_ν$, combining the neutrino flux suppression with the time-delay signature: the best constrained lifetime is that of $ν_1$, which has the richest electronic component. We find $τ_{ν_1}\gtrsim 4\times 10^5~$s at $95\%~$C.L. The tightest $95\%~$C.L. bound on the neutrino mass we find is $0.34~$eV, which is not only competitive with the tightest neutrino mass limits nowadays, but also comparable to future laboratory direct mass searches. Both mass and lifetime limits are independent on the mass ordering, which makes our results very robust and relevant.

hep-ph

Impact of nuclear matrix element calculations for current and future neutrinoless double beta decay searches

Nuclear matrix elements (NME) are a crucial input for the interpretation of neutrinoless double beta decay data. We consider a representative set of recent NME calculations from different methods and investigate the impact on the present bound on the effective Majorana mass $m_{ββ}$ by performing a combined analysis of the available data as well as on the sensitivity reach of future projects. A crucial role is played by the recently discovered short-range contribution to the NME, induced by light Majorana neutrino masses. Depending on the NME model and the relative sign of the long- and short-range contributions, the current $3σ$ bound can change between $m_{ββ} < 40$ meV and 600 meV. The sign-uncertainty may either boost the sensitivity of next-generation experiments beyond the region for $m_{ββ}$ predicted for inverted mass ordering or prevent even advanced setups to reach this region. Furthermore, we study the possibility to distinguish between different NME calculations by assuming a positive signal and by combining measurements from different isotopes. Such a discrimination will be impossible if the relative sign of the long- and short-range contribution remains unknown, but can become feasible if $m_{ββ} \gtrsim 40$ meV and if the relative sign is known to be positive. Sensitivities will be dominated by the advanced $^{76}$Ge and $^{136}$Xe setups assumed here, but NME model-discrimination improves if data from a third isotope is added, e.g., from $^{130}$Te or $^{100}$Mo.

hep-ph

An absolute $ν$ mass measurement with the DUNE experiment

Time of flight delay in the supernova neutrino signal offers a unique tool to set model-independent constraints on the absolute neutrino mass. The presence of a sharp time structure during a first emission phase, the so-called neutronization burst in the electron neutrino flavor time distribution, makes this channel a very powerful one. Large liquid argon underground detectors will provide precision measurements of the time dependence of the electron neutrino fluxes. We derive here a new $ν$ mass sensitivity attainable at the future DUNE far detector from a future supernova collapse in our galactic neighborhood, finding a sub-eV reach under favorable scenarios. These values are competitive with those expected for laboratory direct neutrino mass searches.

hep-ph