Related papers: $\mu\to e \gamma$ Decay in an MSSM Extension
Fermion mass matrices generally rotate in generation space under scale changes, which can lead to fermions of different generations transmuting into one another. The effect is examined in detail and its cross-section calculated for $\gamma…
We present a limit on the branching fraction for the decay $B^0 \to \gamma \gamma$ using data collected at the $\Upsilon(4S)$ resonance with the BABAR detector at the PEP-II asymmetric--energy $e^+e^-$ collider. Based on the observation of…
We discuss the fine-tuning issue within the MSSM framework. Following the idea that the fine-tuning can measure effects of some missing mechanism, we impose non-universal gaugino masses at the GUT scalem and explore the low scale…
Two decay channels $h\rightarrow \gamma \gamma, Z\gamma$ of the Standard Model-like Higgs in a left-right symmetry model are investigated under recent experimental data. We will show there exist one-loop contributions that affect the…
The combined CMS and ATLAS analysis of \(h \to Z\gamma\) reveals a \(2\sigma\) excess over the Standard Model (SM) prediction, hinting at potential new physics. In contrast, the observed agreement of \(\mu_{\gamma\gamma}\) with the SM…
The decay of $B^*_{s,d} \to \mu^+ \mu^-$~ and its impact on $B_{s,d} \to \mu^+ \mu^-$ is studied here. The $ \mu^+ \mu^-$ decay widths of vector mesons $B^*_{s,d}$ are about a factor of 700 larger than the corresponding scalar mesons…
In this work the following lepton flavor violating $\tau$ and $\mu$ decays are studied: $\tau^- \to \mu^- \mu^- \mu^+$, $\tau^- \to e^- e^- e^+$, $\mu^- \to e^- e^- e^+$, $\tau^- \to \mu^- \gamma$, $\tau^- \to e^- \gamma$ and $\mu^- \to e^-…
The radiative decay of the next-to-lightest neutralino into a lightest neutralino and a photon is analyzed in the MSSM. We find that significant regions of the supersymmetric parameter space with large radiative BR's (up to about 100%) do…
The minimal supersymmetric standard model (MSSM) with universal soft breaking terms has a negligible effect on the rare $c\to u\gamma$ decay rate. We therefore study a general model with non-universal soft breaking terms constrained by…
In the absence of any additional assumption it is natural to conjecture that sizeable flavour-mixing mass entries, $\Delta m^2$, may appear in the mass matrices of the scalars of the MSSM, i.e. $\Delta m^2\sim O(m^2)$. This flavour…
The MEG Experiment searches for a lepton flavour violating decay, $\mu^+\to\mathrm{e}^+\gamma $, with a branching-ratio sensitivity of $10^{-13}$ in order to explore the parameter region predicted by many theoretical models beyond the…
We present a complete analysis of the one loop electroweak corrections to $e^-e^+\to\gamma\gamma, ~Z\gamma, ~ZZ$ in the Standard (SM) and the Minimal Supersymmetric Standard Model (MSSM). Analytic expressions are written for the…
Recent analyses have shown that a sequential fourth generation can be consistent with precision electroweak data. We consider the possibility that the new generation could be a mirror generation with $V+A$ rather than $V-A$ interactions.…
We study both the branching ratio for $b \to s \gamma$ decay and the muon anomalous magnetic moment, $a_{\mu} \equiv (g-2)_{\mu} /2$, in the minimal supersymmetric standard model with gauge-mediated supersymmetry breaking. Combining new…
We present the results of a complete analysis of the one loop electroweak corrections to $e^-e^+\to\gamma\gamma, ~Z\gamma, ~ZZ$ in the Standard (SM) and the Minimal Supersymmetric Standard Model (MSSM). A special emphasis is put on the high…
We present the results of the complete one-loop computation of the $B^0_{d,s}\to l^+l^-$ decay rate in the MSSM. Both sources of the FCNC, the CKM matrix and off-diagonal entries of the sfermion mass matrices are considered. Strong…
Extending the Higgs sector of the MSSM by the addition of a gauge singlet scalar field can remedy the mu problem. We explore the implications of extended models for both the spectrum of the neutralinos and the cascade decays of the…
The effect of loops involving charginos with up-type squarks, and gluinos with down-type squarks, on the inclusive decay mode $b\rightarrow s\gamma$ is studied in the context of minimal $N=1$ Supergravity models with a radiatively broken…
The latest measurement of the K_S to gamma gamma branching ratio clearly shows an enhancement over the current theoretical prediction. As in other K and B meson decays, this invites to consider the possibility of the contribution of new…
Lepton flavor violating decays $\ell_{\alpha} \to \ell_{\beta} \gamma$, being forbidden in the Standard Model framework, provide a sensitive probe for new physics. We study these processes in a seesaw variant in which small neutrino masses…