The stransverse mass, M _{T2} , in special cases Article

First Online: 16 May 2011 Received: 07 April 2011 Accepted: 08 May 2011 DOI :
10.1007/JHEP05(2011)076

Cite this article as: Lester, C.G. J. High Energ. Phys. (2011) 2011: 76. doi:10.1007/JHEP05(2011)076 Abstract This document describes some special cases in which the stransverse mass, M _{T2} , may be calculated by non-iterative algorithms. The most notable special case is that in which the visible particles and the hypothesised invisible particles are massless — a situation relevant to its current usage in the Large Hadron Collider as a discovery variable, and a situation for which no analytic answer was previously known. We also derive an expression for M _{T2} in another set of new (though arguably less interesting) special cases in which the missing transverse momentum must point parallel or anti parallel to the visible momentum sum. In addition, we find new derivations for already known M _{T2} solutions in a manner that maintains manifest contralinear boost invariance throughout, providing new insights into old results. Along the way, we stumble across some unexpected results and make conjectures relating to geometric forms of M _{eff} and H _{T} and their relationship to M _{T2} .

Keywords Supersymmetry Phenomenology

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© SISSA, Trieste, Italy 2011

Authors and Affiliations 1. University of Cambridge, Department of Physics, Cavendish Laboratory Cambridge U.K.