Search

We study the mass bounds of the WR gauge boson in generic left-right symmetric models. Assuming that the gauge bosons couple universally to quarks and leptons, we allow different gauge couplings gR≠gL and mass mixing VLCKM≠VRCKM in the left and right sectors. Imposing constraints from collider experiments and K0, Bd, Bs physics, we investigate scenarios where WR is lighter or heavier than the right-handed neutrino νR. In these scenarios, WR mass bounds can be considerably relaxed, while ZR mass bounds are much more stringent. In the case where MWR≤MνR, the experimental constraints come from the WR→tb and WR→jj channels, while if MWR≥MνR, the dominant constraints come from WR→ℓℓjj. The observed (expected) limits in the two-dimensional (MWR, MνR) mass plane excluded at the 95% confidence level extend to approximately MWR=3.1 (3.3) TeV in the ee channel and 3.3 (3.4) TeV in the (μμ) channel, for a large range of right-handed neutrino masses up to MνR=2.1(2.1) TeV in the ee channel and 2.6 (2.5) TeV in the (μμ) channel, representing a significant relaxation of the mass bounds. [ABSTRACT FROM AUTHOR]

A study of the top quark flavor changing neutral current (FCNC) through Z-boson has been performed in the proposed future e-p collider for the energy, Ee(p)=60(7000)GeV. We considered an effective theory where the anomalous FCNC couplings are of vector and tensor nature. The effect of these couplings is probed in the single top production along with the scattered electron. The polar angle θ of the electrons coming out of the primary vertex in association with the top quark polarization asymmetries constructed from the angular distribution of the secondary lepton arising from the top decay, allow to distinguish the Lorentz structure of the coupling. From a multiparameter analysis, we obtain a reach of O(10-2) in the case of Ztu and Ztc couplings at an integrated luminosity of 2ab-1 at 95% C.L. [ABSTRACT FROM AUTHOR]

In the next-to-minimal supersymmetric standard model (NMSSM), it is possible to have strong mass degeneracies between the new singletlike scalar and the heavy doubletlike scalar, as well as between the singletlike and doubletlike pseudoscalar Higgs states. When the difference in the masses of such states is comparable with the sum of their widths, the quantum mechanical interference between their propagators can become significant. We study these effects by taking into account the full Higgs boson propagator matrix in the calculation of the production process of τ+τ- pairs in gluon fusion at the Large Hadron Collider (LHC). We find that, while these interference effects are sizeable, they are not resolvable in terms of the distributions of differential cross sections, owing to the poor detector resolution of the τ+τ- invariant mass. They are, however, identifiable via the inclusive cross sections, which are subject to significant variations with respect to the standard approaches, wherein the propagating Higgs bosons are treated independently from one another. We quantify these effects for several representative benchmark points, extracted from a large set of points, obtained by numerical scanning of the NMSSM parameter space, that satisfy the most important experimental constraints currently available. [ABSTRACT FROM AUTHOR]