Inclusive search for supersymmetry using the razor variables in pp collisions at sqrt(s) = 7 TeV

TL;DR

An inclusive search is presented for new heavy particle pairs produced in √s=7 TeV proton-proton collisions at the LHC using 4.7±0.1 fb(-1) of integrated luminosity using generic supersymmetry models with minimal assumptions about the superpartner decay chains.

Abstract

An inclusive search is presented for new heavy particle pairs produced in sqrt(s) = 7 TeV proton-proton collisions at the LHC using 4.7 +/- 0.1 inverse femtobarns of integrated luminosity. The selected events are analyzed in the 2D razor space of MR, 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 stop or sbottom quarks is excluded for masses as high as 400 GeV.

Figures (4)

• Figure 1: Projection of the 2D fit result on $M_\mathrm{R}$ (top) and $R^2$ (bottom) for the HAD box. The blue histogram is the total standard model prediction as obtained from a single pseudo-experiment based on the 2D fit. The red and green histograms represent a steep-slope component denoted as $V+\text{jets}$ first component, and a component that encapsulates the steep-slope first component in ${t}\overline{{t}}\xspace + \text{jets}$ and the effective second component, which is indistinguishable for the different SM background processes. The fit is performed in the $R^2$-$M_\mathrm{R}$ fit region (FR as shown in Fig. \ref{['fig:blue-plot']}) and projected into the full analysis region. Only the statistical uncertainty band on the background predictions is drawn in these projections.
• Figure 2: The p-values corresponding to the observed number of events in the HAD box signal regions (SR$i$). The green region indicates the fit region (FR) 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$1 standard deviation uncertainty band) 95% CL limits in the ($m_{0}$, $m_{1/2}$) CMSSM plane (drawn according to Rony) with $\tan\beta=10$, $A_{0} = 0$$\,\text{Ge\spaceV}$, and $\mathop{\mathrm{sgn}}\nolimits(\mu) = +1$. Shown separately are the observed HAD-only (solid crimson) and leptonic-only (solid green) 95% CL 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.