119181109
Generation of axionlike couplings via quantum corrections in a Lorentz-violating background
Light pseudoscalars, or axion like particles (ALPs), are much studied due to their potential relevance to the fields of particle physics, astrophysics and cosmology. The most relevant coupling of ALPs from the viewpoint of current experimental searches is to the photon: in this work, we study the generation of this coupling as an effect of quantum corrections, originated from an underlying Lorentz violating background. Most interestingly, we show that the interaction so generated turns out to be Lorentz invariant, thus mimicking the standard ALPs coupling to the photon that is considered in the experiments. This consideration implies that violations of spacetime symmetries, much studied as possible consequences of physics in very high energy scales, might infiltrate in other realms of physics in unsuspected ways. Additionally, we conjecture that a similar mechanism can also generate Lorentz invariant couplings involving scalar particles and photons, playing a possible role in the phenomenology of Higgs bosons.
2496873
Complete low-energy effective action in N=4 SYM: A Direct N=2 supergraph calculation
Using the covariant N=2 harmonic supergraph techniques we calculate the one-loop low-energy effective action of N=4 super-Yang–Mills theory in Coulomb branch with gauge group SU(2) spontaneously broken down to U(1). The full dependence of the low-energy effective action on both the hypermultiplet and gauge fields is determined. The direct quantum calculation confirms the correctness of the exact N=4 SYM low-energy effective action derived in hep-th/0111062 on the purely algebraic ground by invoking a hidden N=2 supersymmetry which completes the manifest N=2 one to N=4. Our results provide an exhaustive solution to the problem of finding out the exact completely N=4 supersymmetric low-energy effective action for the theory under consideration.
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.
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.
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.
14464191
Constraining New Physics from D0-anti-D0 mixing
I review constraints on possible New Physics interactions from D0-anti-D0 mixing measurements. I consider the most general low energy effective Hamiltonian and include leading order QCD running of effective operators. I discuss constraints from an extensive list of popular New Physics models, each of which could be discovered at the LHC, that can generate these operators. In most of the scenarios, strong constraints that surpass those from other search techniques could be placed on the allowed parameter space using the existent evidence for observation of D-meson mixing.
17373947
How to trap a non-standard penguin? Isospin symmetry violations in B-decays with enhanced chromomagnetic dipole operator
Abstract A recently proposed non-standard model solution to the problem of low semileptonic branching ratio B SL which suggests a large branching ratio for the decay b → sg is critically examined. It is shown that the effects of the enhanced chromomagnetic dipole operator might lead to significant violations of isospin symmetry in rate radiative decays of B -mesons.
118105588
Width difference in the D0-anti-D0 system
The motivation most often cited in searches for D0-anti-D0 mixing lies with the possibility of observing a signal from new physics which dominates that from the Standard Model. We discuss recent theoretical and experimental results in D0-anti-D0 mixing, including new experimental measurements from CLEO and FOCUS collaborations and their interpretations.
16727874
Spectator effects and lifetimes of heavy hadrons
We present a calculation of subleading 1/m{sub b} corrections to spectator effects in the ratios of beauty hadron lifetimes in heavy-quark expansion. We find that these effects are sizable and should be taken into account in systematic analyses of heavy hadron lifetimes. In particular, the inclusion of 1/m{sub b} corrections brings into agreement the theoretical predictions and experimental observations of the ratio of lifetimes of {lambda}{sub b} baryon and B{sub d} meson. We obtain {tau}(B{sub u})/{tau}(B{sub d})=1.06{+-}0.02, {tau}(B{sub s})/{tau}(B{sub d})=1.00{+-}0.01, {tau}({lambda}{sub b})/{tau}(B{sub d})=0.86{+-}0.05.
119379339
Neutrinos in a left-right model with a horizontal symmetry
We analyze the lepton sector of a left-right model based on the gauge group SU(2){sub L}xSU(2){sub R}xU(1), concentrating mainly on neutrino properties. Using the seesaw mechanism and a horizontal symmetry, we keep the right-handed symmetry breaking scale relatively low, while simultaneously satisfying phenomenological constraints on the light neutrino masses. We take the right-handed scale to be of order 10's of TeV and perform a full numerical analysis of the model's parameter space, subject to experimental constraints on neutrino masses and mixings. The numerical procedure yields results for the right-handed neutrino masses and mixings and the various CP-violating phases. We also discuss phenomenological applications of the model to neutrinoless double beta decay, lepton-flavor-violating decays (including decays such as {tau}{yields}3{mu}) and leptogenesis.