Scattering of Heavy Stable Exotic Hadrons

The observation of exotic stable massive particles (SMPs) with electric, magnetic or colour charge (or combinations thereof) would be of fundamental significance. Searches are therefore routinely made for SMPs bound in matter, and for SMPs at cosmic ray and collider experiments [1, 2, 3, 4]. Furthermore, SMPs with masses at the TeV scale are anticipated in a number of beyond-the-Standard-Model scenarios, such as supersymmetry and universal extra dimensions [4]. SMP searches are thus a key component of the early data exploitation program of the LHC experiments [5]. To facilitate such searches, models are needed of the interactions of SMP as they pass through matter, since such interactions can give rise to a range of different event topologies [4]. Although robust phenomenological approaches are available to predict the scattering of electromagnetically charged SMPs, it is not clear how the interactions of hadronic SMPs (hereafter termed R-hadrons) should be treated owing to uncertainties associated with the strong scattering processes and the hadronic mass hierarchy. This paper describes an implementation within Geant-4 [6] and extension of a Regge-based model [7] for hadronic scattering. The paper is a summary of work contained in Ref. [8]. To aid the development of search strategies, it is important that experiments have access to Monte Carlo models which span as fully as possible the range of conceivable signatures which could be associated with R-hadron production. At present, one model is available within Geant-4 [9]. This model, hereafter termed the generic model, is based on a black disk approximation [10] and employs pragmatic assumptions regarding possible scattering processes and stable R-hadron species. This work concerns an approach, hereafter termed the Regge model, which uses triple regge formalism to predict the scattering of R-hadrons formed from exotic colour triplet squarks (stop-like (t̃) and sbottom-like (b̃)) and electrically neutral gluino-like (g̃) colour octet particles. Furthermore, the model uses a different set of well motivated assumptions regarding R-hadron mass hierarchies than those employed in the generic model.