Search results for "Yukawa [coupling]"
showing 10 items of 110 documents
Magnetized discs and photon rings around Yukawa-like black holes
2021
We present stationary solutions of geometrically thick discs (or tori) endowed with a self-consistent toroidal magnetic field distribution surrounding a non-rotating black hole in an analytical, static, spherically-symmetric $f(R)$-gravity background. These $f(R)$-gravity models introduce a Yukawa-like modification to the Newtonian potential, encoded in a single parameter $\delta$ which controls the strength of the modified potential and whose specific values affect the disc configurations when compared to the general relativistic case. Our models span different magnetic field strengths, from purely hydrodynamical discs to highly magnetized tori. The characteristics of the solutions are ide…
Higgs production and decay in models of a warped extra dimension with a bulk Higgs
2014
Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS5 space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusion and the H → γγ decay rate and show that they are finite (at one-loop order) as a consequence of gauge invariance. The extended scalar sector comprising the Kaluza-Klein excitations of the Standard Model …
Adiabatic regularization with a Yukawa interaction
2017
We extend the adiabatic regularization method for an expanding universe to include the Yukawa interaction between quantized Dirac fermions and a homogeneous background scalar field. We give explicit expressions for the renormalized expectation values of the stress-energy tensor $\langle T_{\mu\nu} \rangle$ and the bilinear $\langle \bar\psi\psi\rangle$ in a spatially flat FLRW spacetime. These are basic ingredients in the semiclassical field equations of fermionic matter in curved spacetime interacting with a background scalar field. The ultraviolet subtracting terms of the adiabatic regularization can be naturally interpreted as coming from appropriate counterterms of the background fields…
Feynman diagrams as a weight system: four-loop test of a four-term relation
1996
At four loops there first occurs a test of the four-term relation derived by the second author in the course of investigating whether counterterms from subdivergence-free diagrams form a weight system. This test relates counterterms in a four-dimensional field theory with Yukawa and $\phi^4$ interactions, where no such relation was previously suspected. Using integration by parts, we reduce each counterterm to massless two-loop two-point integrals. The four-term relation is verified, with $ = 0 - 3\zeta_3 + 6\zeta_3 - 3\zeta_3 = 0$, demonstrating non-trivial cancellation of the trefoil knot and thus supporting the emerging connection between knots and counterterms, via transcendental number…
General parametrization of Majorana neutrino mass models
2020
We discuss a general formula which allows to automatically reproduce experimental data for Majorana neutrino mass models, while keeping the complete set of the remaining model parameters free for general scans, as necessary in order to provide reliable predictions for observables outside the neutrino sector. We provide a proof of this master parametrization and show how to apply it for several well-known neutrino mass models from the literature. We also discuss a list of special cases, in which the Yukawa couplings have to fulfill some particular additional conditions.
Lagrangians for Massive Dirac Chiral Superfields
2016
A variant for the superspin one-half massive superparticle in $ 4D $, $ \mathcal{N}=1 $, based on Dirac superfields, is offered. As opposed to the current known models that use spinor chiral superfields, the propagating fields of the supermultiplet are those of the lowest mass dimensions possible: scalar, Dirac and vector fields. Besides the supersymmetric chiral condition, the Dirac superfields are not further constrained, allowing a very straightforward implementation of the path-integral method. The corresponding superpropagators are presented. In addition, an interaction super Yukawa potential, formed by Dirac and scalar chiral superfields, is given in terms of their component fields. T…
Master Majorana neutrino mass parametrization
2019
After introducing a master formula for the Majorana neutrino mass matrix, we present a master parametrization for the Yukawa matrices automatically in agreement with neutrino oscillation data. This parametrization can be used for any model that induces Majorana neutrino masses. The application of the master parametrization is also illustrated in an example model, with special focus on its lepton flavor violating phenomenology.
Flavoured leptogenesis: A successful thermal leptogenesis withN1mass below 108GeV
2009
We prove that taking correctly into account the lepton flavour dependence of the CP asymmetries and washout processes, it is possible to obtain successful thermal leptogenesis from the decays of the second right-handed neutrino. The asymmetries in the muon and tau-flavour channels are then not erased by the inverse decays of the lightest right-handed neutrino, N1. In this way, we reopen the possibility of 'thermal leptogenesis' in models with a strong hierarchy in the right-handed Majorana masses that is typically the case in models with up-quark–neutrino Yukawa unification.
An A4 model for neutrinos
2010
Proceedings of PASCOS 2010, the 16th International Symposium on Particles, Strings and Cosmology. 19 - 23 July 2010. Valencia (Spain)
Theory of non-equilibrium critical phenomena in three-dimensional condensed systems of charged mobile nanoparticles.
2014
A study of 3d electrostatic self-assembly (SA) in systems of charged nanoparticles (NPs) is one of the most difficult theoretical problems. In particular, the limiting case of negligible or very low polar media (e.g. salt) concentration, where the long-range NP interactions cannot be reduced to commonly used effective short-range (Yukawa) potentials, remains unstudied. Moreover, the present study has demonstrated that unlike the Debye–Huckel theory, a complete screening of the charges in SA kinetics (dynamic SA) is not always possible. Generally speaking, one has to take into account implicitly how each NP interacts with all other NPs (the true long-range interactions). Traditional theoreti…