A search for R-parity violating Supersymmetric top decays at CMS with \(\sqrt{s} = 8\) TeV

Abstract

A search for a supersymmetric top decay assuming a 100% branching ratio of \(\widetilde{t}\widetilde{t}^* \rightarrow \mu^+ \mu ^- b \overline{b}\) is presented using a minimally supersymmetric model at an integrated luminosity of \(19.5\ \mathrm{fb}^{-1}\). The datasets were recorded with the CMS detector at the LHC. Using Baysian marginalization, an upper limit on the cross section of this process is computed and a cut off point is calculated below which the data does not support the presence of the target decay. This cut off point was calculated to be around 780 GeV.

Introduction

\label{sect:introduction}

With the discovery of the Higgs, the Standard Model seems to offer a complete tally of the fundamental particles with which all of the matter around us is made.(Aad 2012) However, with this answer comes more questions as phenomena such as the origin of dark matter and the seemingly unnatural Higgs mass remain unanswered, and cause theorists to look for physics beyond the Standard Model.

Supersymmetry is one such theory and proposes an extension to space-time which allows for a symmetry relating the two groups of fundamental particles: fermions and bosons, where each of the particles from one group have a corresponding supersymmetric partner differing by half-integer spin. These supersymmetric partners provide opposite quantum corrections to the mass of the Higss and thus yield a natural explanation for the Higss mass. Associated with this extension is a quantum number \(R\), defined as

\[R = (-1)^{(3B + L + 2S)}\]

where S, B, and L, are the spin, baryon, and lepton quantum numbers of the particle.(Huh 2009)

It is important to note that due to the definition of this qu