Supersymmetry and the LHC inverse problem

Abstract

Given experimental evidence at the LHC for physics beyond the standard model, how can we determine the nature of the underlying theory? We initiate an approach to studying the "inverse map" from the space of LHC signatures to the parameter space of theoretical models within the context of low-energy supersymmetry, using 1808 LHC observables including essentially all those suggested in the literature and a 15 dimensional parametrization of the supersymmetric standard model. We show that the inverse map of a point in signature space consists of a number of isolated islands in parameter space, indicating the existence of "degeneracies"-qualitatively different models with the same LHC signatures. The degeneracies have simple physical characterizations, largely reflecting discrete ambiguities in electroweak-ino spectrum, accompanied by small adjustments for the remaining soft parameters. The number of degeneracies falls in the range 1 < d < 100, depending on whether or not sleptons are copiously produced in cascade decays. This number is large enough to represent a clear challenge but small enough to encourage looking for new observables that can further break the degeneracies and determine at the LHC most of the SUSY physics we care about. Degeneracies occur because signatures are not independent, and our approach allows testing of any new signature for its independence. Our methods can also be applied to any other theory of physics beyond the standard model, allowing one to study how model footprints differ in signature space and to test ways of distinguishing qualitatively different possibilities for new physics at the LHC.

Discovery and measurement of sleptons, binos, and winos with aZ′

“…However, we expect a dramatic decrease in such degeneracies compared to the general MSSM. This agrees with the observation made in [5] in the case of on-shell sleptons. Therefore, since a B − xL Z ′ generically gives us a new source of on-shell sleptons, we will be better able to untangle the electroweak-ino sector.…”

Where the sidewalk ends: jets and missing energy search strategies for the 7 TeV LHC

“…While still model-dependent, simplified models help reduce model dependence that often plague top-down parameterizations of new physics. Simplified models have been used in the context of solving the "LHC Inverse Problem" [40] and also in characterizing experimental anomalies [36]. Other approaches in reducing model dependence of searches have been to more fully explore the 19 parameter "phenomenological MSSM" [41,42].…”

Search for Higgs bosons of the universal extra dimensions at the large Hadron collider

“…Conservation of KK-parity is very central to the phenomenology of MUED and is similar in its ramifications to R-parity of SUSY scenarios. Vigorous efforts are on [8,11,14,41,42,43,44,45,47,46,48,49,50,51,52,53,54,55,56,57] in chalking out strategies and their respective efficiencies to distinguish between these two contending scenarios under different situations. These efforts broadly exploits two salient differences between the two scenarios.…”