119202862
Note on the Gauss-Bonnet braneworld scenario
In this work we deal with the presence of braneworld solutions in a ve-dimensional space-time with a single extra spatial dimension of innite extent. The braneworld scenario is built under the presence of a single real scalar eld, and we modify the gravity sector to include generic function of the Gauss-Bonnet term. We study several specic models, and we construct exact braneworld solutions, in particular for including the Gauss-Bonnet term at rst and second order power. As an interesting result, we show that the brane tends to split for a specic modication in the gravity sector, in the presence of non constant Gauss-Bonnet term.
118435943
Equivalence between supersymmetric self-dual and Maxwell–Chern–Simons models coupled to a matter spinor superfield
Abstract We study the duality of the supersymmetric self-dual and Maxwell–Chern–Simons theories coupled to a fermionic matter superfield, using a master action. This approach evades the difficulties inherent to the quartic couplings that appear when matter is represented by a scalar superfield. The price is that the spinorial matter superfield represents a unusual supersymmetric multiplet, whose main physical properties we also discuss.
118455730
Effective potential for a SUSY Lee–Wick model: The Wess–Zumino case
Using a superfield generalization of the tadpole method, we study the one-loop effective potential for a Wess–Zumino model modified by a higher derivative term, inspired by the Lee–Wick model. The one-loop Kahlerian potential is also obtained by other methods and compared with the effective potential.
118533824
Free energy of Lorentz-violating QED at high temperature
In this paper we study the one- and two-loop contribution to the free energy in QED with Lorentz symmetry breaking introduced via constant CPT-even Lorentz-breaking parameters at the high temperature limit. We find the impact of the Lorentz-violating term for the free energy and carry out a numerical estimation for the Lorentz-breaking parameter.
119211852
Lorentz violation and the proper-time method
Abstract In this Letter, we apply the proper-time method to generate the Lorentz-violating Chern–Simons terms in the four-dimensional Yang–Mills and non-linearized gravity theories. It is shown that the coefficient of the induced Chern–Simons term is finite but regularization dependent.
96444982
Horava-Lifshitz-like extensions of supersymmetric theories
Within the superfield approach, we formulate two different extensions of the Wess-Zumino model and super-QED with Horava-Lifshitz-like additive terms, discuss their quantum properties and calculate lower contributions to the effective action. In the case of the gauge theory, the one-loop effective potential turns out to be gauge independent.
119248767
The flavor puzzle in multi-Higgs models
We reconsider the flavor problem in the models with two Higgs doublets. By studying two generation toy models, we look for flavor basis independent constraints on Yukawa couplings that will give us the mass hierarchy while keeping all Yukawa couplings of the same order. We then generalize our findings to the full three generation Standard Model. We find that we need two constraints on the Yukawa couplings to generate the observed mass hierarchy, and a slight tuning of Yukawa couplings of order 10%, much less than the Standard Model. We briefly study how these constraints can be realized, and show how flavor changing currents are under control for $ K - \bar{K} $ mixing in the neardecoupling limit.
118893294
CP-VIOLATION AND MIXING IN CHARMED MESONS
The Standard Model contribution to D0 D 0 mixing is dominated by the contributions of light s and d quarks. Neglecting the tiny effects due to b quark, both mass and lifetime differences vanish in the limit of SU(3)F symmetry. Thus, the main challenge in the Standard Model calculation of the mass and width difference in the D0 D 0 system is to estimate the size of SU(3) breaking effects. We prove that D meson mixing occurs in the Standard Model only at second order in SU(3) violation. We consider the possibility that phase space effects may be the dominant source of SU(3) breaking. We find that y = (�) /(2) of the order of one percent is natural in the Standard Model, potentially reducing the sensitivity to new physics of measurements of D meson mixing. We also discuss the possibility of observing lifetime differences and CP violation in charmed mesons both at the currently operating and proposed facilities.
118410106
Lifetime difference in Bs mixing: Standard Model and beyond
Abstract We present a calculation of 1 / m b 2 corrections to the lifetime differences of B s mesons Δ Γ B s in the heavy-quark expansion. We find that they are small to significantly affect Δ Γ B s and present the result for lifetime difference including non-perturbative 1 / m b and 1 / m b 2 corrections. We also analyze the generic Δ B = 1 New Physics contributions to Δ Γ B s and provide several examples.
118688648
Lepton flavor-violating transitions in effective field theory and gluonic operators
Lepton flavor-violating processes offer interesting possibilities to probe new physics at multi-TeV scale. We discuss those in the framework of effective field theory, emphasizing the role of gluonic operators. Those operators are obtained by integrating out heavy quarks that are kinematically inaccessible at the scale where low-energy experiments take place and make those experiments sensitive to the couplings of lepton flavor-changing neutral currents to heavy quarks. We discuss constraints on the Wilson coefficients of those operators from the muon conversion ${\ensuremath{\mu}}^{\ensuremath{-}}+(A,Z)\ensuremath{\rightarrow}{e}^{\ensuremath{-}}+(A,Z)$ and from lepton flavor-violating tau decays with one or two hadrons in the final state, e.g., $\ensuremath{\tau}\ensuremath{\rightarrow}\ensuremath{\ell}{\ensuremath{\eta}}^{(\ensuremath{'})}$ and $\ensuremath{\tau}\ensuremath{\rightarrow}\ensuremath{\ell}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ with $\ensuremath{\ell}=\ensuremath{\mu},e$. To illustrate the results we discuss explicit examples of constraining parameters of leptoquark models.
119111543
Searching for light dark matter in heavy meson decays
Beauty and charm e + e ― factories running at resonance thresholds have unique capabilities for studies of the production of light dark matter particles in the decays of B q (D) meson pairs. We provide a comprehensive study of light dark matter production in heavy meson decays with missing energy E in the final state, such as B q (D 0 ) → E and B q (D 0 ) → γE. We argue that such transitions can be studied at the current flavor factories (and future superflavor factories) by tagging the missing-energy decays with B(D 0 ) decays "on the other side.".