Inclusive Search for Supersymmetry Using Razor Variables in $pp$ Collisions at $\sqrt{s}\mathbf{=}7\mathrm{TeV}$

An inclusive search is presented for new heavy particle pairs produced in $\sqrt{s}=7\mathrm{TeV}$ proton-proton collisions at the LHC using $4.7\pm 0.1{\mathrm{fb}}^{-1}$ of integrated luminosity. The selected events are analyzed in the 2D razor space of $M_R$, an event-by-event indicator of the heavy particle mass scale, and $R$, a dimensionless variable related to the missing transverse energy. The third-generation sector is probed using the event heavy-flavor content. The search is sensitive to generic supersymmetry models with minimal assumptions about the superpartner decay chains. No excess is observed in the number of events beyond that predicted by the standard model. Exclusion limits are derived in the CMSSM framework as well as for simplified models. Within the CMSSM parameter space considered, gluino masses up to 800 GeV and squark masses up to 1.35 TeV are excluded at 95% confidence level depending on the model parameters. The direct production of pairs of top or bottom squarks is excluded for masses as high as 400 GeV.

Figure 1

Projection of the 2D fit result on $M_R$ (left) and $R^2$ (right) for the HAD box. The blue histogram is the total standard model prediction. The red and green histograms represent a steep-slope component denoted as $V+\mathrm{\text{jets}}$ first component, and a component that encapsulates both the steep-slope first component in $t\overline{t}+\mathrm{\text{jets}}$ and the effective second component, which is indistinguishable for the different SM background processes. The fit is performed in the $R^2\mathrm{\text{−}}{M}_R$ fit region (FR as shown in Fig. 2) and projected into the full analysis region. The full error on the total background prediction is drawn in these projections, including the one due to variation of the nuisance parameters.

Figure 2

The $p$ values corresponding to the observed number of events in the HAD box signal regions ($\mathrm{SR}i$). The green region indicates the fit region in the HAD box. Similar results are obtained for the other boxes.

Figure 3

Observed (solid blue curve) and median-expected (dashed curve, shown with its $\pm 1$ standard deviation uncertainty band) 95% C.L. limits in the ($m_0$, $m_{1/2}$) CMSSM plane (drawn according to [61]) with $\tan \beta =10$, $A_0=0\mathrm{GeV}$, and $\mathrm{sgn}(\mu )=+1$. Shown separately are the observed HAD-only (solid crimson) and leptonic-only (solid green) 95% C.L. limits.

Figure 4

Summary of the 95% CL excluded largest parent mass as a function of the LSP mass in each of the simplified models studied. Results from the inclusive razor analysis (upper bars) and the $b$-jet razor analysis (lower bars) are shown.