arXiv subjects

L. P. S. Leal

Publications and source records attributed to L. P. S. Leal.

4 recordsLinked to original sources

arXiv2026

Neutrinoless Double-Beta Decays from Operator Mixing

We perform a complete one-loop Renormalization Group (RG) analysis of neutrinoless double-beta decays within the Standard Model Effective Field Theory (SMEFT). Although several effective operators do not contribute to these processes at tree level, we show that they can generate sizable contributions through operator mixing. By accounting for the full one-loop RG evolution within the SMEFT, we find that the resulting constraints provide the most stringent bounds on numerous dimension-seven operators, improving upon limits derived from meson decays. We also highlight the importance of contributions beyond the first leading logarithm, which can provide the leading effects for specific operators and flavor combinations.

hep-ph↗

arXiv2025

Flavor constraints from $pp\to Vh$ and $pp\to VW$ at the LHC

We investigate the potential of associated Higgs $pp\to Vh$ and diboson production $pp\to VW$ channels at the LHC (with $V=W,Z$) to constrain flavor-physics operators. Within a general Effective Field Theory (EFT) framework, we derive the helicity amplitudes for these processes at high energies and identify the leading contributions from dimension-six operators involving different quark flavors. Using available LHC data, we show that these processes are sensitive to non-trivial flavor structures and provide complementary constraints to those from low-energy observables. We illustrate this synergy through an explicit comparison between our LHC bounds with electroweak precision data, and with flavor limits derived from charged-current pion and kaon decays. In particular, we show that our HL-LHC projections can probe viable EFT scenarios proposed to accommodate the discrepancies in the extraction of the Cabibbo angle.

hep-ph↗

arXiv2024

Correlating $0νββ$ decays and flavor observables in leptoquark models

In this paper, we investigate minimal scalar leptoquark models that dynamically generate neutrino Majorana masses at the one-loop level and examine their implications for low-energy processes. We show that these models can produce viable neutrino masses, consistent with neutrino oscillation and cosmological data. By using leptoquark couplings fixed by neutrino data, we predict additional contributions to neutrinoless double-beta decays ($0νββ$), which are chirality enhanced and compete with the standard contributions from the Majorana masses. Our analysis demonstrates that these effects are sizable for leptoquark masses as large as $\mathcal{O}(300~\mathrm{TeV})$, potentially increasing or decreasing the $0νββ$ half-life, and creating an ambiguity between the normal and inverted mass ordering scenarios. Furthermore, we explore the correlation between $0νββ$ and flavor observables, such as kaon decays and $μ\to e$ conversion in nuclei, emphasizing that the latter is complementary to $0νββ$ decays.

hep-ph↗

arXiv2024

Disentangling left and right-handed neutrino effects in $B\rightarrow K^{(*)}νν$

The first observation of $\mathcal{B}\left(B^+\rightarrow K^+νν\right)$ by the Belle II experiment lies almost $3σ$ away from the Standard Model expectation. In this letter we study this result in the SMEFT, extended by a light right-handed neutrino. We explore the correlations between the measured decay rate and other observables, such as $\mathcal{B}\left(B\rightarrow K^*νν\right)$ and $F_L\left(B\rightarrow K^*νν\right)$, showing that they could disentangle among scenarios involving left-handed neutrinos and those with the right-handed ones. Furthermore, we find that the high-$p_T$ tails of Drell-Yan processes studied at LHC provide important constraints that help us exclude some of the scenarios consistent with the Belle II result.

hep-ph↗