arXiv subjects

R. Barbieri

Publications and source records attributed to R. Barbieri.

21 records · Page 2Linked to original sources

arXiv1994

Strings versus supersymmetric GUTs: can they be reconciled?

We describe a class of supersymmetric unified models with the following properties: i) the full breaking of the gauge group is achieved by Higgs fields in the fundamental representation; ii) the correct unification of the strong and electroweak coupling constants is obtained without the need of any intermediate scale; iii) the problems of the doublet-triplet splitting and of the proton decay at dimension-5 level may receive a natural solution. The models, other than being interesting unified field theories per se, may constitute examples of string-derivable GUTs.

hep-ph↗

arXiv1993

Phenomenological Implications of Supersymmetry Breaking by the Dilaton

We investigate the low energy properties of string vacua with spontaneously broken $N=1$ supersymmetry by a dilaton $F$-term. As a consequence of the universal couplings of the dilaton, the supersymmetric mass spectrum is determined in terms of only three independent parameters and more constrained than in the minimal supersymmetric Standard Model. For a $μ$-term induced by the \K\ potential the parameter space becomes two-dimensional; in the allowed regions of this parameter space we find that most supersymmetric particles are determined solely by the gluino mass. The Higgs is rather light and the top-quark mass always lower than 180 GeV.

hep-ph↗

arXiv1993

$b \to s γ$ Decay and Supersymmetry

The inclusive radiative $B$-decay is a sensitive probe of new physics, especially if related to the virtual exchange of a charged Higgs boson. Supersymmetric models provide a particularly interesting example. In the limit of exact supersymmetry, BR($b \to sγ$)~=~0, due to the vanishing of any magnetic-moment transition operator. We illustrate the impact of this constraint for realistic values of the supersymmetry-breaking parameters.

hep-ph↗