We investigate the LHC discovery potential of R-parity violating supersymmetric models with a right-handed selectron or smuon as the lightest supersymmetric particle (LSP). These LSPs arise naturally ...in R-parity violating minimal supergravity models. We classify the hadron collider signatures and perform for the first time within these models a detailed signal over background analysis. We develop an inclusive three-lepton search and give prospects for a discovery at a center-of-mass energy of 7 TeV as well as 14 TeV. There are extensive parameter regions which the LHC can already test with 7 TeV and an integrated luminosity of 1 inverse femtobarn. We also propose a method for the mass reconstruction of the supersymmetric particles within our models at 14 TeV.
We consider the embedding of the supersymmetric Standard Model with broken R-parity in the minimal supergravity (mSUGRA) model. We restrict ourselves to the case of broken lepton number, the B3 ...mSUGRA model. We first study in detail how the tree-level neutrino mass depends on the mSUGRA parameters. We find in particular a strong dependence on the trilinear supersymmetry breaking A-parameter, even in the vicinity of the mSUGRA SPS1a point. We then reinvestigate the bounds on the trilinear R-parity violating couplings at the unification scale from the low-energy neutrino masses including dominant one-loop contributions. These bounds were previously shown to be very strict, as low as O(10^{-6}) for SPS1a. We show that these bounds are significantly weakened when considering the full mSUGRA parameter space. In particular the ratio between the tree-level and 1-loop neutrino masses is reduced such that it may agree with the observed neutrino mass hierarchy. We discuss in detail how and in which parameter regions this effect arises.
Many extensions of the leptonic sector of the Minimal Supersymmetric Standard Model (MSSM) are known, most of them leading to observable flavor violating effects. It has been recently shown that the ...1-loop contributions to lepton flavor violating three-body decays \(l_i \to 3 l_j\) involving the \(Z^0\) boson may be dominant, that is, much more important than the usual photonic penguins. Other processes like \(\mu\)-\(e\) conversion in nuclei and flavor violating \(\tau\) decays into mesons are also enhanced by the same effect. This is for instance also the case in the MSSM with trilinear R-parity violation. The aim of this work is to derive new bounds on the relevant combinations of R-parity violating couplings and to compare them with previous results in the literature. For heavy supersymmetric spectra the limits are improved by several orders of magnitude. For completeness, also constraints coming from flavor violating \(Z^0\)-decays and tree-level decay channels \(l \to l_i l_j l_k\) are presented for a set of benchmark points.
We consider minimal supergravity (mSUGRA) models with an additional R-parity violating operator at the grand unification scale. This can change the supersymmetric spectrum leading on the one hand to ...a sneutrino, smuon or squark as the lightest supersymmetric particle (LSP). On the other hand, a wide parameter region is reopened, where the scalar tau is the LSP. It is vital to know the nature of the LSP, because supersymmetric particles normally cascade decay down to the LSP at collider experiments. We investigate in detail the conditions leading to non-neutralino LSP scenarios. We also present some typical LHC signatures.
We investigate, which lightest supersymmetric particles can be obtained via a non-vanishing lepton- or baryon-number violating operator at the grand unification scale within the R-parity violating ...minimal supergravity model. We employ the full one-loop renormalization group equations. We take into account restrictions from the anomalous magnetic moment of the muon and b -> s gamma, as well as collider constraints from LEP and the Tevatron. We also consider simple deformations of minimal supergravity models.
We investigate the discovery potential of the LHC experiments for R-parity violating supersymmetric models with a stau as the lightest supersymmetric particle (LSP) in the framework of minimal ...supergravity. We classify the final states according to their phenomenology for different R-parity violating decays of the LSP. We then develop event selection cuts for a specific benchmark scenario with promising signatures for the first beyond the Standard Model discoveries at the LHC. For the first time in this model, we perform a detailed signal over background analysis. We use fast detector simulations to estimate the discovery significance taking the most important Standard Model backgrounds into account. Assuming an integrated luminosity of 1 inverse femtobarn at a center-of-mass energy of 7 TeV, we perform scans in the parameter space around the benchmark scenario we consider. We then study the feasibility to estimate the mass of the stau-LSP. We briefly discuss difficulties, which arise in the identification of hadronic tau decays due to small tau momenta and large particle multiplicities in our scenarios.
Using the example of selected decays driven by R-parity-violating supersymmetric operators, we demonstrate how strong final-state interactions can be controlled quantitatively with high precision, ...thus allowing for a more accurate extraction of effective parameters from data. In our examples we focus on the lepton-flavor-violating decays tau --> mu pi+ pi-. In R-parity violation these can arise due to the product of two couplings. We find bounds that are an order of magnitude stronger than previous ones.
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