We report on our recent work on electroweak corrections to tt̄ production at hadron colliders. Specifically, we discuss the weak-interaction contributions to the top quark transverse momentum and tt̄ invariant mass distributions and an induced parity-violating top-spin asymmetry. PACS number(s): 12.15.Lk, 12.38.Bx, 13.88.+e, 14.65.Ha

We present a simple theory where baryon and lepton numbers are spontaneously broken at the supersymmetry scale. In this context R-parity must be spontaneously broken but the theory still contains a stable field which can play the role of the cold dark matter of the Universe. We discuss the spectrum of the theory, the properties of the dark matter candidate and the predictions for direct detecti...

We consider eeqq contact interactions as a possible origin of an excess of events above Standard Model predictions in e + p ! e + jet at high Q 2 observed by the H1 and ZEUS collaborations at HERA. The HERA data prefer chirality RL or LR contact terms and atomic physics parity violation measurements severely limit parity-odd contact terms. With equal left-right and right-left chirality interact...

We start with a brief presentation of the Standard Model and the weak neutral current, in view of a discussion of parity-violation in electron-hadron electroweak interactions. We then discuss some limitations of this model, motivating the consideration of larger frameworks such as grand-unification and supersymmetry. We also comment about the possible effects of additional light neutral gauge b...

In these Lectures we review the Minimal Supersymmetric Standard Model as well as some of its extensions that include R–Parity violation. The cases of spontaneous breaking of R–Parity as well as that of explicit violation through bilinear terms in the superpotential are studied in detail. The signals at LEP and the prospects for LHC are discussed. 1 Lectures given at the V Gleb Wataghin School, ...

The aim of the future linear colliders is to extend the sensitivity to new physics beyond the reach of the Lhc. Several models predict the existence of new vector resonances in the multi-TeV region. We review the existing limits on the masses of these new resonances from Lep/Slc and Tevatron data and from the atomic parity violation measurements, in some specific models. We study the potential ...

Strangeness content is one of the most important questions in hadron structure because it sheds light on the role of the quark-anti quark sea in the ground state properties. One important tool is elastic parity-violating electron-proton scattering, which has been used to probe the the charge and magnetization distributions of the strange quark within the nucleon. At the tree level, the parity-v...

We study an MSSM model with bilinear R-parity violation which is capable of explaining neutrino data while leading to testable predictions for ratios of LSP decay rates. Further, we estimate the precision with which such measurements could be carried out at the LHC.

We construct two SUSY SU (3) ⊗ SU (2) L ⊗ U (1) electroweak models with su-perweak R-parity violation. The scale of R-parity violation in one of the models is determined by the Majorana mass of neutrino and it is very small that leads to the existence of longlived (T ≥ O(10 −4)sec) lightest superparticle. If lightest superpar-ticle is righthanded charged slepton that can be realized within gaug...

We discuss lepton flavour violating signals at the LHC in the framework of supersymmetric theories. We consider R-parity conserving as well as R-parity violating scenarios. In the case of R-parity conservation we show that in decays of supersymmetric particles large regions in parameter exist where lepton flavour violating decay modes have large branching ratios despite the stringent constraint...