Search for Top Squarks at Tevatron Inspired by Dark Matter and Electroweak Baryogenesis

Abstract

The search for the top squark (${\tilde{t}}_1$) within the kinematic reach of Tevatron Run II is of great contemporary interest. Such a ${\tilde{t}}_1$ can explain the baryon asymmetry of the universe provided $120GeV/c^2\le m_{{\tilde{t}}_1}\le m_t$. Moreover if $\Delta m\equiv m_{{\tilde{t}}_1}$ - $m_{{\tilde{\chi }}_1^0}$ is small, where ${\tilde{\chi }}_1^0$ is the LSP, the dark matter relic density as obtained from the WMAP data may be explained via ${\tilde{t}}_1$- LSP coannihilation. In this scenario the decay ${\tilde{t}}_1\to c{\tilde{\chi }}_1^0$ is likely to occur with 100 % branching ratio but for small $\Delta m$ the conventional di-jet + $/E_T$ signal becomes unobservable. We propose a new search strategy based on the $2j+/E_T$ signature accompanied by an isolated cluster of energy which arises from a decaying heavy particle with characteristic decay length. Our preliminary simulations with PYTHIA indicate that for $100GeV/c^2\le m_{{\tilde{t}}_1}\le 130GeV/c^2$ this signal may be observable while somewhat lager $m_{{\tilde{t}}_1}$ may still provide hints of new physics.

14 pages, 6 figures

References in corpus (1)

• Search for scalar top quarks in the acoplanar charm jets and missing transverse energy final state in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV