Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · 2610.01808

Probing the neutrino mass through semileptonic decays

Claire Chevallier
View original source ↗Read source document ↗Export metadata ↓

Abstract

We argue that a detailed analysis of semileptonic decays can test the possibility of a massive neutrino. The key observable, related to the forward-backward asymmetry, is exactly zero for a massless neutrino but becomes non-zero if the neutral lepton is heavy and interacts with Standard Model fields via left-handed operators. For right-handed interactions, this quantity differs significantly from zero even for a massless right-handed neutrino. We demonstrate this explicitly using the example of a pseudoscalar meson decaying into another pseudoscalar meson.

Explore related subjects

hep-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Claire Chevallier. 2026-10-01. Probing the neutrino mass through semileptonic decays. https://arxiv.org/abs/2610.01808

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Factorization in deep inelastic scattering at Björken limit: Reduction to (1+1)D integrable models

We study the small-$x$ behavior of the proton structure function $F_2(x,Q^2)$ using the combined HERA inclusive deep-inelastic-scattering data and compare it with exact structure functions obtained in integrable quantum field theories. The data are described by a local power law, $F_2(x,Q^2)=A(Q^2)x^{-γ(Q^2)}$, where the exponent $γ(Q^2)$ increases smoothly with the hard scale. We show that this running exponent is well described by a simple renormalization-group crossover form and approaches the limiting value $C=γ(\infty)\simeq0.431$. This value selects the sine-Gordon power-law universality class among the exactly solvable possibilities and corresponds to the coupling $β^2/π=16/(3-C)\simeq6.23$. The sine-Gordon-constrained fit gives a quantitatively accurate description of the HERA $F_2$ surface, with reduced $χ^2$ close to unity, and is independently supported by the final HERA reduced-cross-section data. These results indicate that the small-$x$ growth observed in deep inelastic scattering is naturally organized by a sine-Gordon-type universality class, while the finite-$Q^2$ dependence is controlled by a smooth crossover toward the corresponding asymptotic exponent.

hep-ph↗
arXiv2026

U-spin symmetry energy and hyperon puzzle in $Λ$-admixed neutron stars

By combining the ($u$,$d$) I-spin doublets or ($d$,$s$) U-spin doublets, the SU(3) flavor symmetry of light quarks can be decomposed into SU(2)$_I\times$U(1)$_Y$ or SU(2)$_U\times$U(1)$_Q$ subgroups, which have been widely adopted to categorize hadrons and their decay properties. The standard I-spin counterpart for the interactions among nucleons, namely the nuclear symmetry energy $E_\mathrm{sym}(n_\mathrm{b})$, characterizes the variation of binding energy as the neutron to proton ratio in a nuclear system. We propose the U-spin symmetry energy $E_\mathrm{U}(n_\mathrm{b})$ for hyperonic matter to characterize the variation of binding energy with the inclusion of hyperons. In particular, we include $Λ$ hyperons in dense matter and neglect contributions from other hyperons, then constrain $E_\mathrm{U}(n_\mathrm{b})$ using nuclear physics and astrophysical observations through a Bayesian inference approach. Our results show that $E_\mathrm{U}(n_\mathrm{b})$ is much smaller than 9$E_\mathrm{sym}(n_\mathrm{b})$, indicating a substantially weaker dependence of the adopted binding energy functional on the U-spin asymmetry than on the corresponding I-spin asymmetry. Consequently, the $Λ$ hyperon potential increases significantly with density and becomes repulsive at higher densities, leading to more than 50\% probability for the emergence of $Λ$ hyperons in the posterior, which are likely to vanish again at densities $n_\mathrm{b} \gtrsim 5\,n_0$. In scenarios where $Λ$ hyperons do emerge, the onset density $n_{\mathrm{b}}^Λ$ typically falls in the range $2\,n_0$--$5\,n_0$, corresponding to central densities of neutron stars more massive than $1.0\,\rm{M_\odot}$.

hep-ph↗
arXiv2026

Momentum-projected hadron entanglement from lattice-QCD replica correlators

We define a finite-volume lattice-QCD observable for the vacuum-subtracted spatial Rényi response of a source--sink-prepared, momentum-projected hadron. At fixed regulator, integer replica index $n>1$, spatial region and gauge-theory cut prescription, double-sided state projection expresses this response as a ratio of replicated and ordinary hadron correlators. The first numerical target is the $n=2$ ratio; its proposed $L^{-3}$ scaling at fixed physical region is to be tested with matched volumes. We implement the measurement in quenched SU(3) for a charged pseudoscalar meson with heavy degenerate Wilson valence quarks, $am_{\rm eff}\simeq2.07$, on two $16^3\times32$ sheets with a central-plaquette cut. Five finite balls and empty/full controls are measured at nine source/sink placements. Their finite-ball means increase with radius at every placement. At the reference placement the three largest responses are 1.6--2.5 times an ideal single-quasiparticle occupancy reference. A full-covariance fit $Δ_{\rm cp}=κ_{\rm occ}S_2^{\rm occ}$ gives $κ_{\rm occ}=1.68\pm0.12$; radius-window and full-control comparisons give values spanning $1.49$--$1.73$. An exact pure-state quark--antiquark pair model interpolates, in the dilute limit, between the unit-occupancy reference ($κ_{\rm occ}=1$) for an unresolved meson and the double-occupancy reference ($κ_{\rm occ}=2$) for a separately resolved quark and antiquark, and yields a boundary-area correction governed by their separation.

hep-ph↗