Supersymmetry tests at Fermilab: A proposal

Abstract

We compute the number of trilepton events to be expected at Fermilab as a result of the reaction P p -~f~;~, where x f is the lightest chargino and X: is the next-to-lightest neutralino. This signal is expected to have very little background and is the best prospect for supersymmetry detection at Fermilab if the gluino and squarks are beyond reach. We evaluate our expressions for all points in the allowed parameter space of two basic supergravity models: (i) the minimal SU(5) supergravity model including the severe constraints from proton decay and a not too young universe and (ii) a recently proposed no-scale flipped SU(5) supergravity model. We study the plausible experimental scenarios and conclude that a large portion of the parameter spaces of these models could be explored with 100 pb-' of integrated luminosity. In the minimal SU(5) supergravity model chargino masses as high as 100 GeV could be probed. In the no-scale flipped model it should be possible to probe some regions of parameter space with m + 5 175 GeV, therefore, possibly exceeding the reach of the CERN LEP I1 for chargino and Xineutralino (since m ,=m + ) masses. In both models such probes would indirectly explore gluinox,

Direct detection of dark matter in SU(5) × U(1) supergravity

“…The computations of B(b → sγ) in supergravity models in Ref. [11], in particular for no-scale SU(5) × U(1) supergravity, indicate that b → sγ is an important constraint only for µ > 0, and even in that case only for tan β > ∼ 4. Therefore, even assuming that the b → sγ constraints are rigorous, there should still be a large portion of the parameter space accessible to direct searches of dark matter.…”

“…At LEPII, chargino masses as high as 100 GeV should be readily detectable in all the scenarios which we have considered here [5,6], and yet, direct detection of the LSP with m χ 0 1 ≈ 1 2 m χ ± 1 < ∼ 50 GeV may take a while to occur. Indirect detection of dark matter via upwardly moving muon fluxes in neutrino telescopes may taken even longer to happen, as explicit calculations show in the models we considere here [12] and more generally in model-independent analyses [13].…”

“…The effect of several other direct and indirect experimental constraints have been discussed in Refs. [5,6]. These models have the features of universal soft-supersymmetry-breaking at the unification scale and radiative breaking of the electroweak symmetry, which is enforced by minimizing the one-loop effective potential.…”

Higgs boson decays into light gravitinos

“…[3] and [13], respectively. In particular the LEP1 constraint (3a) is very restrictive [3], if mχ0 1 < M Z . Further constraints on the relevant parameter space can be derived from the negative outcome of chargino searches.…”

“…Recently models with a very light gravitino G [1], m G ≤ 10 −3 eV, have attracted some attention [2,3,4]. This interest was originally triggered by the resurgence of models [5] where supersymmetry breaking is transmitted by gauge interactions to the "visible sector" containing the usual gauge, Higgs and matter superfields, although these models tend to predict m G ≥ 1 eV.…”