New limits on top squark NLSP from ATLAS 4.7 $fb^{-1}$ data

TL;DR

This paper sets new experimental limits on the mass of the top squark when it is the next-to-lightest supersymmetric particle, using ATLAS data, thereby constraining models of supersymmetry and baryogenesis.

Contribution

It provides updated mass limits on the top squark NLSP considering all decay modes, based on ATLAS 4.7 fb^{-1} data, refining previous constraints on supersymmetric models.

Findings

Lower limit on top squark mass is 240 GeV if $ ilde t_1 o c ilde au_1$ dominates.

Lower limit on top squark mass is 200 GeV if $ ilde t_1 o b W ilde au_1$ dominates.

Constraints on top squark NLSP induced baryogenesis are now more stringent.

Abstract

Using the ATLAS 4.7 $fb^{-1}$ data on new physics search in the jets + $\met$ channel, we obtain new limits on the lighter top squark ($\tilde t_1$) considering all its decay modes assuming that it is the next to lightest supersymmetric particle (NLSP). If the decay $\lstop$ $\ra c \lspone$ dominates and the production of dark matter relic density is due to NLSP - LSP co-annihilation then the lower limit on $\mlstop $ is 240 GeV. The limit changes to 200 GeV if the decay $\lstop$ $\ra b W \lspone$ dominates. Combining these results it follows that $\lstop $ NLSP induced baryogenesis is now constrained more tightly.