Electric dipole moment constraints on CP-violating heavy-quark Yukawas at next-to-leading order

Electric dipole moments are sensitive probes of new phases in the Higgs Yukawa couplings. We calculate the complete two-loop QCD anomalous dimension matrix for the mixing of CP-odd scalar and tensor operators and apply our results for a phenomenological study of CP violation in the bottom and charm Yukawa couplings. We find large shifts of the induced Wilson coefficients at next-to-leading-logarithmic order. Using the experimental bound on the electric dipole moments of the neutron and mercury, we update the constraints on CP-violating phases in the bottom and charm quark Yukawas.

The CKM phase and $$ \overline{\theta} $$ in Nelson-Barr models

We analyze the Nelson-Barr approach to the Strong CP Problem. We derive the necessary conditions in order to simultaneously reproduce the CKM phase and the quark masses. Then we quantify the irreducible contributions to the QCD topological angle, namely the corrections arising from loops of the colored fermion mediators that characterize these models. Corrections analytic in the couplings first arise at 3-loop order and are safely below current bounds; non-analytic effects are 2-loop order and decouple as the mediators exceed a few TeV. We discuss collider, electroweak, and flavor bounds and argue that most of the parameter space above the TeV scale is still allowed in models with down-type mediators, whereas other scenarios are more severely constrained. With two or more families of mediators the dominant experimental bound is due to the neutron electric dipole moment.

Searching for GeV-scale Majorana Dark Matter: inter spem et metum

We suggest a minimal model for GeV-scale Majorana Dark Matter (DM) coupled to the standard model lepton sector via a charged scalar singlet. We show that there is an anti-correlation between the spin-independent DM-Nucleus scattering cross section (σSI) and the DM relic density for parameters values allowed by various theoretical and experimental constraints. Moreover, we find that even when DM couplings are of order unity, σSI is below the current experimental bound but above the neutrino floor. Furthermore, we show that the considered model can be probed at high energy lepton colliders using e.g. the mono-Higgs production and same-sign charged Higgs pair production.

Boosting GWs in supersolid inflation

Inflation driven by a generic self-gravitating medium is an interesting alternative to study the impact of spontaneous spacetime symmetry breaking during a quasi de-Sitter phase, in particular the 4-dimensional diffeomorphism invariance of GR is spontaneously broken down to I SO(3). The effective description is based on four scalar fields that describe the excitations of a supersolid. There are two phonon-like propagating scalar degrees of freedom that mix non-trivially both at early and late times and, after exiting the horizon, give rise to non-trivial correlations among the different scalar power spectra. The non-linear structure of the theory allows a secondary gravitational waves production during inflation, efficient enough to saturate the present experimental bound and with a blue-tilted spectral index.

Renormalizable SO(10) GUT with Suppressed Dimension-5 Proton Decays

We study a renormalizable SUSY SO(10) GUT model where the Yukawa couplings of single 10, single $${\bf \overline{126}}$$ and single 120 fields, Y10, Y126, Y120, account for the quark and lepton Yukawa couplings and the neutrino mass. We pursue the possibility that Y10, Y126, Y120 reproduce the correct quark and lepton masses, CKM and PMNS matrices and neutrino mass differences, and at the same time suppress dimension-5 proton decays (proton decays via colored Higgsino exchange) through their texture, so that the soft SUSY breaking scale can be reduced as much as possible without conflicting the current experimental bound on proton decays. We perform a numerical search for such a texture, and investigate implications of that texture on unknown neutrino parameters, the Dirac CP phase of PMNS matrix, the lightest neutrino mass and the (1, 1)-component of the neutrino mass matrix in the charged lepton basis. Here we concentrate on the case when the active neutrino mass is generated mostly by the Type-2 seesaw mechanism, in which case we can obtain predictions for the neutrino parameters from the condition that dimension-5 proton decays be suppressed as much as possible.

Quantum-corrected thermodynamics and P–V criticality of self-gravitating Skyrmion black holes

We study the quantum-corrected thermodynamics of a class of black holes generated by self-gravitating Skyrmion models. One such black hole solution is the Einstein–Skrymion black hole. We first compute the Arnowitt–Deser–Misner mass of an Einstein–Skyrmion black hole using an on-shell Hamiltonian formalism already present in the literature. We then consider nonextended phase space thermodynamics and derive expressions for various thermodynamic quantities like the Hawking temperature, entropy, pressure, Gibbs free energy, and heat capacity. Next, we study the effect of quantum corrections on the thermodynamics of the Einstein–Skyrmion black hole. We observe that apart from leading to stability, the quantum correction induces an anti-de Sitter to de Sitter phase transition in the Einstein–Skrymion black hole. Treating the cosmological constant as the pressure, we determine the $P$–$V$ criticality of the Einstein–Skrymion black hole and observe that it depends on the model parameters $\lambda$ and $K$. This study of the $P$–$V$ criticality could help to estimate the experimental bound on the values of $\lambda$ and $K$.

Neutrino–antineutrino mass splitting in the Standard Model: Neutrino oscillation and baryogenesis

By adding a neutrino mass term to the Standard Model, which is Lorentz and [Formula: see text] invariant but nonlocal to evade CPT theorem, it is shown that nonlocality within a distance scale of the Planck length, that may not be fatal to unitarity in generic effective theory, can generate the neutrino–antineutrino mass splitting of the order of observed neutrino mass differences, which is tested in oscillation experiments, and non-negligible baryon asymmetry depending on the estimate of sphaleron dynamics. The one-loop order induced electron–positron mass splitting in the Standard Model is shown to be finite and estimated at [Formula: see text], well below the experimental bound [Formula: see text]. The induced CPT violation in the K-meson in the Standard Model is expected to be even smaller and well below the experimental bound [Formula: see text].

Study ofχc01P→J/ψγandχb0(1P)→Υ1SγDecays via QCD Sum Rules

We present the calculation of the form factor of theχc01P→J/ψγandχb0(1P)→Υ1Sγ decays in the frame work of QCD sum rules. We also find branching ratioBrχc01P→J/ψγ=1.36-0.6+0.9×10-2which is in agreement with the experimental data. Furthermore, we estimate theΓtot(χb0(1P))=4.2-2.21+3.18 MeV, where experimental bound for full width ofχb0is Γtot(χb0(1P))<6 MeV.