arXiv subjects

Joao Paulo Pinheiro

Publications and source records attributed to Joao Paulo Pinheiro.

5 recordsLinked to original sources

arXiv2026

Lessons from the first JUNO results

First results from the JUNO reactor neutrino experiment already determine with world-leading precision the small neutrino squared-mass splitting $Δm^2_{21}$ and the mixing angle $θ_{12}$. In this article we perform an exploratory study beyond these, taking advantage of the first JUNO data release to discuss its sensitivity to the large squared-mass splitting, $Δm^2_{3\ell}$. When combined with constraints from global oscillation data, this may already contain some information on the neutrino mass ordering. Indeed, we find that the combination of the complementary $Δm^2_{3\ell}$-determinations gives a slight preference for Normal Ordering, with a p-value for Inverted Ordering of 2%-2.6% ($2.2σ$-$2.3σ$). We study the robustness of this result with respect to potential systematic uncertainties and statistical fluctuations. Taken at face value, a full global analysis of oscillation data including the publicly available JUNO information and data leads to a preference for Normal Ordering with $Δχ^2 = 4.6$ and 9.4 without and with Super-K and IceCube-24 atmospheric neutrino data, respectively.

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arXiv2025

Exploring solutions to the muon g-2 anomaly in a 3-3-1 model under flavor constraints

The magnetic moment of the muon can receive significant two-loop contributions from a light pseudoscalar. Notably, the spectrum of scalars of 3-3-1 models include one pseudoscalar. However this scalar spectrum inevitably gives rise to flavor-changing neutral current (FCNC) processes. In this study, we examine, within the 3-3-1 model with right-handed neutrinos, whether such spectrum of scalars can account for the anomalous magnetic moment of the muon, considering the constraints imposed by $B$-meson decays, meson mixing, and invisible Higgs decays. Our principal finding reveals that a pseudoscalar with mass around 66 GeV and $\tan β=58$ can account for the $g-2$ anomaly without conflicting with flavor physics.

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arXiv2024

Solar neutrinos and leptonic spin forces

We quantify the effects of light spin-zero particles with pseudoscalar couplings to leptons and scalar couplings to nucleons on the evolution of solar neutrinos. In this scenario the matter potential sourced by the nucleons in the Sun's matter gives rise to spin precession of the relativistic neutrino ensemble. As such the effects in the solar observables are different if neutrinos are Dirac or Majorana particles. For Dirac neutrinos the spin-flavour precession results into left-handed neutrino to right-handed neutrino (i.e., active-sterile) oscillations, while for Majorana neutrinos it results into left-handed neutrino to right-handed antineutrino (i.e., active-active) oscillations. In both cases this leads to distortions in the solar neutrino spectrum which we use to derive constraints on the allowed values of the mediator mass and couplings via a global analysis of the solar neutrino data. In addition for Majorana neutrinos spin-flavour precession results into a potentially observable flux of solar electron antineutrinos at the Earth which we quantify and constrain with the existing bounds from Borexino and KamLAND.

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arXiv2022

On the Higgs spectra of the 3-3-1 model with the sextet of scalars engendering the type II seesaw mechanism

In the 3-3-1 model with right-handed neutrinos, three triplets of scalars engender the correct sequence of symmetry breaking, $SU(3)_C \times SU(3)_L \times U(1)_X \rightarrow SU(3)_C \times SU(2)_L \times U(1)_Y \rightarrow SU(3)_C \times U(1)_{EM}$, generating mass for all fermions, except neutrinos. Tiny neutrino masses may be achieved by adding one sextet of scalars to the original scalar content. As consequence, it emerges a very complex scalar sector, involving terms that violate lepton number explicitly, too. The main obstacle to the development of the phenomenology of such scenario is the knowledge of its spectrum of scalars since, now, there are 15 massive scalar particles on it. The proposal of this work is to do an exhaustive analysis of such scalar sector with lepton number being explicitly violated at low, electroweak and high energy scales by means of trilinear terms in the potential. The first case can be addressed analytically and, as a nice result, we have observed that the scalar content of such case is split into two categories: One belonging to the 331 energy scale and the other belonging to the EWSB energy scale, with the last recovering the well known THDM+triplet. For the other cases, the scalar sector can be addressed only numerically. Hence, we proposed a very general approach for the numerical study of the potential, avoiding simplifications that can make us reach conclusions without foundation. We show that, in the case of lepton number being explicitly violated at electroweak scale, it is possible to recover the same physics of the THDM+triplet, as the previous case. Among all the possibilities, we call the attention to one special case which generates the 3HDM+triplet scenario. For the last case, when lepton number is violated at high energy scale, the sextet become very massive and decouples from the original scalar content of the 3-3-1 model.

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arXiv2022

On the Higgs spectra of the 3-3-1 model

The minimal scalar sector of the 3-3-1 model is composed by the SU(3)$_L$ triplet scalars $η$, $ρ$, $χ$ and its potential allows the trilinear term $\frac{f}{\sqrt{2}}χηρ$. Since $f$ is an energy scale associated to the explicit violation of Peccei-Quinn global symmetry, it is natural to consider in what energy scale such symmetry is broken and its consequences in the spectrum of scalars of the model. here, We show that $f$ determines the spectrum of scalars of the model. Hence, we develop the scalar sector considering $f$ belonging to four energy regimes, namely $f \ll \langle η\rangle_0$, $\langle ρ\rangle_0$; $f= \langle η\rangle_0$, $\langle ρ\rangle_0$; $f=\langle χ\rangle_0$ and $f \gg \langle χ\rangle_0$ and obtain the spectrum of scalars for each case. In the first and second cases the spectrum of scalars presents a set of new scalars belonging to the electroweak scale, while in the third case all new scalars belong to the 3-3-1 scale and the fourth case all the new scalars have masses lying at $f$ scale. All cases have a neutral CP-even scalar mimicking the standard Higgs.

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