Search for squarks and gluinos using final states with jets and missing transverse momentum with the ATLAS detector in sqrt(s) = 7 TeV proton-proton collisions

Abstract

A search for squarks and gluinos in final states containing jets, missing transverse momentum and no electrons or muons is presented. The data were recorded by the ATLAS experiment in sqrt(s) = 7 TeV proton-proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in 35 inverse picobarns of analysed data. Gluino masses below 500 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino. The exclusion increases to 870 GeV for equal mass squarks and gluinos. In MSUGRA/CMSSM models with tan(beta)= 3, A_0=0 and mu>0, squarks and gluinos of equal mass are excluded below 775 GeV. These are the most stringent limits to date.

Figures (3)

• Figure 1: The distributions of $m_{\mathrm{eff}}$ (separately for the $\ge 2$ and $\ge 3$ jet regions) and $m_\mathrm{T2}$ are shown for data and for the expected SM contributions after application of all selection criteria -- cuts on the variables themselves are indicated by the red arrows. Also shown is the $E_{\mathrm{T}}^{\mathrm{miss}}$ distribution after the $\ge$2 jet preselection cuts only. For comparison, each plot includes a curve showing the expectation for an MSUGRA/CMSSM reference point with $m_0=200$Ge V, $m_{1/2}=190$Ge V, $A_0=0$, $\tan\beta=3$ and $\mu> 0$. This reference point is also indicated by the star on Figure \ref{['fig:sugraExclusion']}. Below each plot may be seen the ratio of the data to the SM expectation. Black vertical bars show the statistical uncertainty from the data, while the yellow band shows the size of the Standard Model MC uncertainty.
• Figure 2: 95% C.L. exclusion limits in the ($m_{\tilde{g}}$, $m_{\tilde{q}}$) plane together with existing limits Abachi:1995ngAffolder:2001tcAaltonen:2008rv:2007wwAbazov:2009zi. Comparison with existing limits is illustrative only as some are derived in the context of MSUGRA/CMSSM or may not assume $m_{\hbox{$\tilde{\chi}^0_1$}}=0$.
• Figure 3: 95% C.L. exclusion limits in the $\tan\beta=3$, $A_0=0$ and $\mu>0$ slice of MSUGRA/CMSSM, together with existing limits Aaltonen:2008rv:2007wwAbazov:2009ziKhachatryan:2011tk with the different model assumptions given in the legend.