\mu\rightarrow e\gamma decay in the left-right supersymmetric model

We calculate the dipole amplitude for the decay and related processes in the left-right supersymmetric model when parity breaking occurs at a considerably large scale. The low-energy flavor violation in the model originates either from the nonvanishing remnants of the left-right symmetry in the slepton mass matrix or from the direct flavor changing lepton-slepton-neutralino interaction. The result is found to be large and already accessible with current experimental accuracy for supersymmetric masses not far above the electroweak scale. It also provides nontrivial constraints on the lepton mixing in the model. Received: 8 June 1998 / Published online: 15 October 1998     

Chargino-neutralino production inp\bar p-collisions for the left-right supersymmetric model

An extension of the Supersymmetric Standard Model to the supersymmetricSU(2) _L×SU(2) _R×U(1) _B–L model is considered. The gauge group contains a bidoublet and triplet Higgs field. We investigate the possibility of detecting chargino and neutralino production in -collisions atCDF, namely . A numerical analysis is performed for , tan 1 and a lower bound on the lightest supersymmetric particle (LSP) mass, GeV. Using conservative assumptions ofM _WR300 GeV andgg _Lg _R, we find the cross sections are: , and pb, and thus _L 24 _L at TeV. Cross sections are also given for larger values of the center of mass energy up to those available at the SSC. The results are compared with the prompt-lepton background of theW _{L, R} ^– decays from . Both decays for bosons show Jacobian peaks for (p _T150 GeV forM _WR) at =90°. Furthermore the chargino signature unlike the promptlepton background is symmetric under the Jacobian peak. We also exhibit the dependence of the angular distribution of the chargino on the c.m. angle forp _T40 GeV, 150 GeV at TeV.     

Leptonic dipole moments in the left-right supersymmetric model

The observation of neutrino oscillations imposes a pattern of mixing in both the sneutrino and charged slepton sectors. On the other hand, the apparent 2.6 deviation of the anomalous magnetic moment of the muon from the standard model value favors a scenario beyond the standard model. We show that, in a supersymmetric model with left-right symmetry, which provides an explanation for both phenomena, the relationship between flavor conserving dipole moments, such as the magnetic and the electric dipole moments, and flavor violating dipole moments, such as and , is quite different from that in the MSSM. From general analytic considerations, we derive bounds on the fractional sneutrino mass splittings , and the fractional charged slepton splittings . For , the mixing is allowed to be maximal. We also comment on the magnitudes and correlations between CP-violating angles coming from electric dipole moments. We supplement the analytical considerations by detailed numerical calculations. Received: 6 September 2001 / Revised version: 30 October 2001 / Published online: 7 December 2001     

A supersymmetric left-right confining model of the weak interactions

We extend the supersymmetric, confining theory of weak interactions to a left-right symmetric model. This model is based on the gauge group SU(M)_SC×SU(2)_R×SU(2)_L×SU(3)_c×U(1) and is more natural as far as supersymmetry breaking is concerned. Supersymmetry protects chiral symmetries from spontaneous breakdown and allows a solution to the strong CP problem. This model can accommodate at most three generations of quarks and leptons.     

Masses of charginos and neutralinos in a left-right supersymmetric model

We consider chargino and neutralino masses in an extension of the supersymmetric standard model to the supersymmetricSU(2) _L ×SU(2) _R ×U(1) _B-L model. After mixing of gauginos with higgsinos in addition to four charginos there are three neutralinos generated from the first symmetry breaking, and four neutralinos generated from the second symmetry breaking. In the minimal supersymmetry and left-right supersymmetry models, these mixings can be parameterized in terms of a few parameters. We find analytical expressions and numerical solutions for the mass eigenstates with some restrictions on theL-R parameters.     

Implications of $B \to \rho \gamma$ measurements in the standard model and supersymmetric theories

We study the implications of the recently improved upper limits on the branching ratios for the decays , expressed as . We work out the constraints that the current bound on implies on the parameters of the quark mixing matrix in the standard model (SM). Using the present profile of the unitarity triangle, we predict this ratio to lie in the range (at 95% C.L.), with the central value . We also work out the correlations involving , the isospin-violating ratio , and the direct CP-violating asymmetry in decays in the SM, in the minimal supersymmetric extension of the SM (MSSM), and in an extension of the MSSM involving an additional flavor-changing structure in transitions. Received: 19 August 2002 / Published online: 18 October 2002 RID="a" ID="a" e-mail: ali@mail.desy.de RID="b" ID="b" e-mail: lunghi@mail.desy.de     

The b \to X_s \gamma rate and Higgs boson limits in the constrained minimal supersymmetric model

New NLO calculations have become available using resummed radiative corrections. Using these calculations we perform a global fit of the supergravity inspired constrained minimal supersymmetric model. We find that the resummed calculations show similar constraints as the LO calculations, namely that only with a relatively heavy supersymmetric mass spectrum of (1 TeV) the b– Yukawa unification and the rate can coexist in the large scenario. The resummed calculations are found to reduce the renormalization scale uncertainty considerably. The low scenario is excluded by the present Higgs limits from LEP II. The constraint from the Higgs limit in the plane is severe, if the trilinear coupling at the GUT scale is fixed to zero, but is considerably reduced for . The relatively heavy SUSY spectrum required by corresponds to a Higgs mass of GeV in the CMSSM. Received: 14 February 2001 / Revised version: 22 March 2001 / Published online: 29 June 2001     

B^0 - \bar B^0 mixing in a supersymmetric model without at-quark

A model based on a low energySU(3)_c×SU(2)₁×SU(2)₂×U(1) _H gauge group is considered. Theb-quark couples mainly to thec-quark via a new heavyW-boson and thet-quark is omitted altogether. The model is shown to be compatible with low energy charged current data. \(B_d^0 - \bar B_d^0 \) mixing occurs through the exchange of the heavyW-boson and through gluino exchange in the supersymmetric version of the model. The calculated mixing is much smaller in both cases than the observed effect and the model is, therefore, ruled out.     

On the supersymmetric sine-Gordon model

The basic model in a new trend in supersymmetry and soliton theory is presented. Exact soliton-like solutions of the supercovariant coupled equations of motion are obtained. From this a bag model is constructed.Talk given at the ldSymposium on Mathematical Methods in the Theory of Elementary Particles, Liblice castle, Czechoslovakia, June 18–23, 1978.     

\bar v_e e^ - -Annihilation and supersymmetric particles

In the framework of a minimal supersymmetric (s) extension of the standard Glashow-Weinberg-Salam theory, creation of s-partners of known leptons and gauge bosons in the -annihilation is studied. The angle distributions and total cross sections of s-particle creation are investigated in detail. The comparison with similar processes with the participation of known particles is performed. The possibility of an experimental identification of s-particles in the -annihilation is analyzed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 68–74, October, 1989.The authors thank I. M. Zheleznykh for useful discussions.     

Aq-deformed left-right symmetric model

A newq-deformed Left-Right Symmetric model is constructed and the various mass relations and mixing angles are derived. It is shown that the model allows for parity violation, and predicts a new Z’ gauge boson.