We compute the supersymmetry (SUSY) effective Hamiltonian that describes the |ΔS|=1 semileptonic ... more We compute the supersymmetry (SUSY) effective Hamiltonian that describes the |ΔS|=1 semileptonic decays of tau leptons. We provide analytical expressions for supersymmetric contribution to τ→us¯ντ transition in mass insertion approximation. We show that SUSY contributions may enhance the CP asymmetry of τ→Kπντ decays by several orders of magnitude with respect to the standard model expectations. However, the resulting asymmetry is still well below the current experimental limits obtained by CLEO Collaborations. We emphasize that measuring CP rate asymmetry in this decay larger than 10-6 would be a clear evidence of physics beyond the supersymmetric extensions of the standard model.
We analyze the CP violation in the semileptonic |∆S| = 1 τ -decays in supersymmetric extensions o... more We analyze the CP violation in the semileptonic |∆S| = 1 τ -decays in supersymmetric extensions of the standard model (SM) with R parity violating term. We show that the CP asymmetry of τdecay is enhanced significantly and the current experimental limits obtained by CLEO collaborations can be easily accommodated. We argue that observing CP violation in semi leptonic τ -decay would be a clear evidence for R-parity violating SUSY extension of the SM
We analyze the CP violation in the semileptonic |DeltaS|=1 tau decays in supersymmetric extension... more We analyze the CP violation in the semileptonic |DeltaS|=1 tau decays in supersymmetric extensions of the standard model with R parity violating term. We show that the CP asymmetry of tau decay is enhanced significantly and the current experimental limits obtained by CLEO collaborations can be easily accommodated. We argue that observing CP violation in semileptonic tau decay would be a clear evidence for R parity violating supersymmetry extension of the standard model.
We analyze the CP violation in the semileptonic | \Delta S|=1 tau-decays in supersymmetric extens... more We analyze the CP violation in the semileptonic | \Delta S|=1 tau-decays in supersymmetric extensions of the standard model (SM) with R parity violating term. We show that the CP asymmetry of tau-decay is enhanced significantly and the current experimental limits obtained by CLEO collaborations can be easily accommodated. We argue that observing CP violation in semi leptonic tau-decay would be a clear evidence for R-parity violating SUSY extension of the SM.
A non-universal axigluon in generalized chiral color models leads to flavor changing neutral curr... more A non-universal axigluon in generalized chiral color models leads to flavor changing neutral currents (FCNCs) at tree level. We analyze phenomenologically the new contributions to $B_{q}$ (q=d, s) mixing and the related CP asymmetries (CPAs) that are generated by axigluon exchange. We find that although $\Delta m_{B_q}$ can give a strict constraint on the parameters of $b\to q$ transition, the precise measurement of $\sin2\beta_{J/\Psi K^0}$ can further exclude the parameter space of $b\to d$ transition. The axigluon-mediated effects can enhance the like-sign dimuon charge asymmetry ${\cal A}^{b}_{s\ell}$ by one order of magnitude larger than the standard model prediction. Accordingly, large CPA $\sin2\beta^{J/\Psi \phi}_s$ and CPA difference $\sin2\beta_{J\Psi K^0}-\sin2\beta_{\phi K^0}$ are achieved.
In this paper, we study the Cabibbo favored non-leptonic $D^0$ decays into $K^- \pi^+$ decays. Fi... more In this paper, we study the Cabibbo favored non-leptonic $D^0$ decays into $K^- \pi^+$ decays. First we show that, within the Standard Model, the corresponding CP asymmetry is strongly suppressed and out of the experimental range even taking into account the large strong phases coming from final state Interactions. We show also that although new physics models with extra sequential generation can enhance the CP asymmetry by few orders of magnitude however the resulting CP asymmetry is still far from experimental range. The most sensitive New Physics Models to this CP asymmetry comes from no-manifest Left-Right models where a CP asymmetry up to 10% can be reached and general two Higgs models extension of SM where a CP asymmetry of order $10^{-2}$ can be obtained without being in contradiction with the experimental constraints on these models.
We introduce a simple model of dynamical supersymmetry breaking. It is like a supersymmetric vers... more We introduce a simple model of dynamical supersymmetry breaking. It is like a supersymmetric version of a Nambu-Jona-Lasinio model with a spin one composite. The simplest version of the model as presented here has a single chiral superfield (multiplet) with a four-superfield interaction. The latter has the structure of the square of the superfield magnitude square. A vacuum condensate of the latter is illustrated to develop giving rise to supersymmetry breaking with a soft mass term for the superfield. We report also the effective theory picture with a real superfield composite, illustrating the matching effective potential analysis and the vacuum solution conditions for the components. The nature of its fermionic part as the Goldstone mode is presented.
In this paper we discuss Nambu-Jona-Lasinio model as a classical model for dynamical mass generat... more In this paper we discuss Nambu-Jona-Lasinio model as a classical model for dynamical mass generation and symmetry breaking. In addition we discuss the possible supersymmetric extensions of this model resulting from interaction terms with four chiral superfields that may be regarded as a supersymmetric generalization of the four-fermion interactions of the Nambu-Jona-Lasinio model. A four-superfield interaction terms can be constructed as either dimension 6 or dimension 5 operators. Through analyzing solutions to the gap equations, we discuss the dynamical generation of superfield Dirac mass, including a supersymmetry breaking part. A dynamical symmetry breaking generally goes along with the dynamical mass generation, for which a bi-superfield condensate is responsible.
We show that the scalar leptoquark Yukawa couplings generate a significant lepton flavour violati... more We show that the scalar leptoquark Yukawa couplings generate a significant lepton flavour violation. We compute the light scalar leptoquark contributions to the branching ratios (Br) of the lepton flavour violating (LFV) decays $\ell \to \ell_i \ell_j \bar{\ell}_j$ and $\ell \rightarrow \ell^{\prime} \gamma$ with (i,j = e,$\mu$). We discuss the role of the relevant input parameters to these decay rates
We study the theoretical features in relation to dynamical mass generation and symmetry breaking ... more We study the theoretical features in relation to dynamical mass generation and symmetry breaking for the recently proposed holomorphic supersymmetric Nambu-Jona-Lasinio model. The basic model has two different chiral superfields with a strongly coupled dimension five four-superfield interaction. In addition to the possibility of generation of Dirac mass between the pair established earlier, we show here the new option of generation of Majorana masses for each chiral superfield.
We study some implications of the presence of two inert scalar doublets which are charged under a... more We study some implications of the presence of two inert scalar doublets which are charged under a dark Abelian gauge symmetry. Specically, we investigate the eects of the new scalars on oblique electroweak parameters and on the interactions of the 125 GeV Higgs boson, especially its decay modes h → γγ, γZ and trilinear coupling, all of which will be probed with improved precision in future Higgs measurements. Moreover, we explore how the inert scalars may give rise to strongly rst-order electroweak phase transition and also show its correlation with sizable modications to the Higgs trilinear coupling.
We consider some implications of X-ray lines from certain astronomical objects as potential effec... more We consider some implications of X-ray lines from certain astronomical objects as potential effects of dark matter decay in the context of the scotogenic model, where neutrinos acquire mass radiatively via one-loop interactions with dark matter. As an example, we focus on the 3.5 keV line recently detected in the X-ray spectra of galaxy clusters, assuming that it stands future scrutiny. We explore the scenario in which the line originates from the slow decay of fermionic dark matter in the model. After obtaining a number of benchmark points representing the parameter space consistent with the new data and various other constraints, we make predictions on several observables in leptonic processes. They include the effective Majorana mass in neutrinoless double-beta decay, the sum of neutrino masses, and the rate of flavor-changing decay µ → eγ, as well as the cross sections of e + e − collisions into final states containing nonstandard particles in the model. These are testable in ongoing or future experiments and thus offer means to probe the scotogenic scenario studied.
In this paper, we study the Cabibbo favored non-leptonic D 0 decays into K − π + decays. First we... more In this paper, we study the Cabibbo favored non-leptonic D 0 decays into K − π + decays. First we show that, within the Standard Model, the corresponding CP asymmetry is strongly suppressed and out of the experimental range even taking into account the large strong phases coming from final state Interactions. We show also that although new physics models with extra sequential generation can enhance the CP asymmetry by few orders of magnitude however the resulting CP asymmetry is still far from experimental range. The most sensitive New Physics Models to this CP asymmetry comes from no-manifest Left-Right models where a CP asymmetry up to 10% can be reached and general two Higgs models extension of SM where a CP asymmetry of order 10 −2 can be obtained without being in contradiction with the experimental constraints on these models.
We consider nonstandard interactions of neutrinos with electrons arising from a new light spin-1 ... more We consider nonstandard interactions of neutrinos with electrons arising from a new light spin-1 particle with mass of tens of GeV or lower and couplings to the neutrinos and electron. This boson is not necessarily a gauge boson and is assumed to have no mixing with standard-model gauge bosons. Adopting a modelindependent approach, we study constraints on the flavor-conserving and -violating couplings of the boson with the leptons from a number of experimental data. Specifically, we take into account the (anti)neutrinoelectron scattering and e + e − → ννγ measurements and keep explicitly the dependence on the new particle mass in all calculations. We find that one of the two sets of data can provide the stronger constraints, depending on the mass and width of the boson.
We investigate the dynamical mass generation resulted from interaction terms with four chiral sup... more We investigate the dynamical mass generation resulted from interaction terms with four chiral superfields. The kind of interactions maybe considered a supersymmetric generalization of the four-fermion interactions of the classic Nambu-Jona-Lasinio model. A four-superfield interaction that contains a four-fermion interaction as one of its component terms has been the standard supersymmetrization of the NJL model for decades. Recently, we introduced a holomorphic variant with a dimension five interaction term instead. The latter is a main target of the present analysis. With the introduction of a new perspective on the superfield gap equation, we derive it for each one of the four-superfield interactions, using the supergraph technique. Through analyzing solutions to the gap equations, we illustrate the dynamical generation of superfield Dirac mass, including a supersymmetry breaking part.
A non-universal axigluon in generalized chiral color models leads to flavor changing neutral curr... more A non-universal axigluon in generalized chiral color models leads to flavor changing neutral currents (FCNCs) at tree level. We analyze phenomenologically the new contributions to B q (q=d, s) mixing and the related CP asymmetries (CPAs) that are generated by axigluon exchange. We find that although ∆m Bq can give a strict constraint on the parameters of b → q transition, the precise measurement of sin 2β J/ΨK 0 can further exclude the parameter space of b → d transition.
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Papers by Gaber Faisel