arXiv subjects

Guglielmo Papiri

Publications and source records attributed to Guglielmo Papiri.

5 recordsLinked to original sources

arXiv2026

One Sum To Rule Them All: A Second Order Master Rate Sum Rule for Charm Decays

We show that within the Standard Model any system of hadronic weak charm decays related by $U$-spin satisfies the following rate sum rule: (sum of CF and DCS CKM-free rates) divided by (sum of SCS CKM-free rates) = 1, which holds up to second order in $U$-spin breaking. We test this sum rule against available data and find that it is well satisfied in all cases. For systems in which some decay rates have not yet been measured, we use this sum rule to predict the missing rates.

hep-ph↗

arXiv2026

Hydrogenated carbon structures as directional sub-GeV dark matter detectors

We propose hydrogenated carbon structures as targets with a remarkable sensitivity to dark matter-nucleon interactions, in the mass range between the 1 MeV and 100 MeV. The ejection of a proton following the interaction with a dark matter particle is a quasi-elastic process, with an extremely small energy threshold, and a clear experimental signature. The proposed detectors are simple, technologically ready, and inexpensive. Yet, they can be considerably more sensitive than current experiments. They also allow strong directionality, to be used towards efficient background rejection.

hep-ph↗

arXiv2026

$CP$ violation in neutral kaon mixing in $D^0\rightarrow K_SK_S$

We study CP violation induced by neutral kaon mixing in $a_{CP}(D^0 \rightarrow K_S K_S)$. We show that the contribution from neutral kaon mixing arises only in connection with second-order weak interactions in $D$ decays. We estimate this effect to be at the $10^{-6}$ level, and thus negligible compared to current experimental sensitivity and to the expected contribution from CP violation in the charm sector.

hep-ph↗

arXiv2025

CP violation in decays into states with neutral kaons

CP violation in the kaon system can manifest itself in decays to final states containing neutral kaons. The effect is governed by an efficiency function that reflects the specific experimental setup. We demonstrate that this efficiency function factorizes into two components: the kaon energy spectrum and a universal detector-dependent factor. We show that matter effects on kaon oscillations can have a significant effect on CP asymmetries. We provide estimates of the theoretical prediction for some such CP asymmetries for a Belle II-type experiment.

hep-ph↗

arXiv2024

A study of the relativistic corrections to polarized tritium $β$-decay

Forthcoming experiments like Project8 and Ptolemy aim at investigating with high precision the end-point of the tritium $β$-decay spectrum sensitive to the neutrino mass. In light of this, using the standard parametrization in terms of nuclear polar form factors, we analyze the complete relativistic expression for the spectrum of the $β$-electron emitted by a tritium nucleus. Given the small parameters in the problem, we systematically discuss the approximations that can be made, and present the first two corrections to the standard lowest order formula. We particularly discuss the case of an initially polarized target, and the consequences on the spectrum as a function of the neutrino mass. We show that, while it induces an angular anisotropy that can be measured by future experiments, such anisotropy cannot be used as an additional handle to constrain the neutrino mass.

hep-ph↗