Superparticle Signatures: from PAMELA to the LHC

Abstract

Signatures of soft supersymmetry breaking at the CERN LHC and in dark matter experiments are discussed with focus drawn to light superparticles, and in particular light gauginos and their discovery prospects. Connected to the above is the recent PAMELA positron anomaly and its implications for signatures of SUSY in early runs at the Large Hadron Collider. Other new possibilities for physics beyond the Standard Model are also briefly discussed. Dual Probes of SUSYWe review here testable predictions of high scale models with universal and non universal soft [supersymmetry] 1 breaking within the framework of applied supergravity (SUGRA) and effective models of string theories with D-branes supporting chiral gauge theories (for recent related reviews see [2,3]). Common to all these models are the ingredients needed for working in the predictive SUGRA framework, namely: (a) an effective Kähler metric which generally depends on moduli, (b) a gauge kinetic function also dependent on such scalars, and (c) a superpotential comprised of visible and hidden sector fields and a bilinear term for the Higgses.An important set of predictions of the models discussed here is that they can offer the possibility of a relatively light gluino and electroweak gauginos with dark matter which is naturally Majorana. Thus the confluence of LHC signatures and signatures of dark matter play a central role in understanding the predictions of the above models. This connection is illuminated through knowledge of the possible sparticle mass hierarchies that can arise [4]. These mass hierarchies include the possibility of light scalars. However, naturalness/radiative electroweak symmetry breaking (REWSB) tend to point us to light gauginos and heavy squarks which generally occur on the upper Hyperbolic Branch (HB) of REWSB [6] often re-1 For recent clear reviews see [1] ferred to as the focus point (FP) region. This region naturally arises in the minimal supergravity framework [7] and its extensions which are typically perturbations around universality.Towards the end of this overview we will further discuss the connection between dark matter and the LHC, but more specifically in terms of the link between the WMAP data and the recent PAMELA positron excess [8]. Should the PAMELA anomaly be attributed to SUSY dark matter, the eigen-composition of the LSP plays a very relevant role. In addition, the composition of the LSP has important implications for collider signatures, and thus a direct bearing on the discovery prospects of SUSY at LHC, as well as the very nature of how dark matter was produced in the early universe. Resolving the Sparticle LandscapeWe begin with the Sparticle Landscape [4]. Of the 32 massive particles predicted in the MSSM, the number of ways in which the sparticle masses can stack up in their mass hierarchy is a priori undetermined unless an underlying framework is specified. Thus, if the 32 masses are treated as essentially all independent, then aside from sum rules on the Higgs, sfermions, and gaugino masses, and without im...

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R-parity conservation via the Stueckelberg mechanism: LHC and Dark Matter Signals

“…A further generalization to multiple U(1)s reads 8) with N V Abelian vectors and N S axions, where B µ = V µ1 and the other vector fields correspond to either hidden or visible gauge symmetries. Recent works with multiple additional U(1)s have indeed been discussed recently [32,45,[48][49][50][51][52]68]. Our analysis is restricted to non-anomalous extension of the Standard Model (for the anomalous case see e.g.…”

“…Specifically, the class of models that we study here allows for two component (Majorana and Dirac) dark matter [45]. Such models with dark forces have received considerable attention in the context of the recent cosmic anomalies [45][46][47][48][49][50][51]; for recent additional works on dark sectors see e.g. [52][53][54][55][56][57][58][59].…”