Abstract
As experimental constraints on the parameter space of the MSSM and close variations thereof become stronger, the motivation to explore supersymmetric models that challenge some of the standard assumptions of the MSSM also become stronger. For example, models where the gauginos are Dirac instead of Majorana have recently received more attention. Beside allowing for a supersoft SUSY breaking mechanism where the gauginos only provide finite threshold corrections to scalar masses, the cross section for the production of a squark pairs is reduced. In addition, Dirac gauginos can be used to build models that possess a U(1)R symmetry. This symmetry can then be identified with a lepton number, leading to models that are quite different from conventional scenarios. The sneutrinos in these models can acquire a vev and give mass to the leptons and the down-type squark. The phenomenology is novel, combining signatures that are typical of R-parity violating scenarios with signatures arising from leptoquarks. Correspondingly the constraints from electroweak precision data are also different. In these models, one of the leptons mixes with gauginos and superpotential Yukawa couplings can contribute to EWPM at tree level. In addition, lepton universality is broken. In this paper we adapt the operators analysis of Han and Skiba [1] to include the relevant violation of lepton universality, and do a global fit of the model to electroweak precision data, including all relevant tree-level and loop-level effects. We obtain bounds on the vev of the sneutrino and on the superpotential couplings of the model.
Highlights
As experimental constraints on the parameter space of the MSSM and close variations thereof become stronger, the motivation to explore supersymmetric models that challenge some of the standard assumptions of the MSSM become stronger
That such couplings will lead to deviations to electroweak precision observables, and it is the goal of this paper to study more in depth the constraints that electroweak precision observables put on the model
We have studied the bounds that electroweak precision measurements put on a supersymmetric model where a lepton number is identified with a U(1)R symmetry and one of the sneutrino gets a vev and is responsible for giving masses to the downtype quarks and the leptons
Summary
We present a review of the model which was described in details in [18, 19]. The adjoint chiral superfields are added to give Dirac masses to gauginos These masses occur through a superpotential term of the form [5] (shown here for the winos): d2θ. Φ where τ a and λa are respectively the generators of the two and three dimensional representations of SU(2) As mentioned above, it is the sneutrino and not Rd which acquires a vev providing masses to down-type fermions in this model. The part of the superpotential responsible for the masses of the standard model particles will be of the form: W0 = yuQHuU c + ydQLaDc + yeb LaLbEbc + yec LaLcEcc + μHuRd. The subscript a on the lepton chiral superfield denotes the flavor of the sneutrino that acquires a vev. Due to the presence of the Bμ term, the sneutrino νawill acquire one
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
