相关论文: R Parity in Standard--like Superstring Models

Holomorphy of the superpotential promotes any continuous symmetry group G to a complexified symmetry group G_C of the superpotential. For U(1) symmetry this means that the superpotential is not only invariant under U(1) phase rotation but…

Unified models incorporating the right handed neutrino in a symmetric way generically possess parity symmetry. If this is broken spontaneously it results in the formation of domain walls in the early Universe, whose persistence is unwanted.…

We construct basis-independent expressions that measure the magnitude of $R$-parity breaking due to possible superpotential terms in the Minimal Supersymmetric extension of the Standard Model, in the absence of soft supersymmetry-breaking…

We perform a systematic study of the Standard Model embedding in a D-brane configuration of type I string theory at the TeV scale. We end up with an attractive model and we study several phenomenological questions, such as gauge coupling…

We investigate the presence of discrete gauge symmetries in Grand Unification models based in $SO(10)$ and $E_6$. These models include {\it flipped} and {\it unflipped} $SU(5)$, $SU(4)\!\times\! SU(2)_L\!\times\! SU(2)_R$,…

A search for pair-produced scalar fermions under the assumption that R-parity is not conserved has been performed using data collected with the OPAL detector at LEP. The data samples analysed correspond to an integrated luminosity of about…

We analyze the one loop corrections to leptonic W and Z decays in an R-parity violating extension to the Minimal Supersymmetric Standard Model (MSSM). We find that lepton universality violation in the Z line-shape variables alone would…

An extended Hubbard model with phonons is considered on a D-dimensional lattice. The symmetries of the model are studied in various cases. It is shown that for a certain choice of the parameters a superconducting SU_q(2) holds as a true…

We determine the number and distribution of the fermion states in the standard model based on the possible fermion representations of the gauge bosons. By extracting the even parity scalars from the fermion states we suggest the existence…

Generic D-brane string models of particle physics predict the existence of extra U(1) gauge symmetries beyond hypercharge. These symmetries are not of the E_6 class but rather include the gauging of Baryon and Lepton numbers as well as…

I investigate the phenomenology of supersymmetric models with extra vector-like supermultiplets that couple to the Standard Model gauge fields and transform as the fundamental representation of a new confining non-Abelian gauge interaction.…

Current experimental constraints on a large parameter space in supersymmetric models rely on the large missing energy signature. This is usually provided by the lightest neutralino which stability is ensured by the R-parity. However, if the…

A natural origin for the mu and B parameters of weak scale supersymmetric theories is proposed, applicable to any supersymmetry breaking messenger scale between the weak and Planck scales. Although quite general, it requires supersymmetric…

We compute supersymmetric contributions to pion leptonic (\pi_{l2}) decays in the Minimal Supersymmetric Standard Model (MSSM). When R-parity is conserved, the largest contributions to the ratio R_{e/\mu} = \Gamma[ \pi^+ \to e^+…

A generic feature of string-derived models is the appearance of an anomalous Abelian U(1)_A symmetry which, among other properties, constrains the Yukawa couplings and distinguishes the three families from each other. In this paper, we…

We consider the Minimal Supergravity Model with universality of scalar and gaugino masses plus an extra bilinear term in the superpotential which breaks R-Parity and lepton number. We explicitly check the consistency of this model with the…

We study the pattern of gluino cascade decays in a class of supersymmetric models where R-parity is spontaneously broken. The multi-lepton and same-sign dilepton rates in these models are compared with those of the Minimal Supersymmetric…

In the standard model the proton is protected from decay naturally by gauge symmetries, whereas in the ordinary minimal supersymmetric standard model an ad hoc discrete symmetry is imposed for the proton stability. We present a new…

We present a supersymmetric standard model with three gauged Abelian symmetries, of a type commonly found in superstrings. One is anomalous, the other two are $E_6$ family symmetries. It has a vacuum in which only these symmetries are…

We consider electroweak symmetry breaking in supersymmetric models with an extra non-anomalous U(1)' gauge symmetry and an extra standard-model singlet scalar S. For appropriate charges the U(1)' forbids an elementary mu term, but an…