Squark and Gluino Production with Jets

Abstract

We present cross section predictions for squark and gluino production at the LHC, in association with up to two additional hard jets. These cross sections can be very large in comparison to the inclusive Born rates. Because hadron collider experiments utilize hard jets in the reconstruction of cascade decays or as a way to separate squark and gluino production, the understanding of these processes is crucial. We show to what degree hard jet radiation can be described by shower algorithms and point out how tuning these showers, for example to top quark pair production, could help reduce theoretical uncertainties for new physics searches at the LHC.

Figures (2)

• Figure 1: $p_{T,j}$ spectra for $t\bar{t},\tilde{g}\tilde{g}$ and $\tilde{u}_{{L}}\tilde{u}_{{L}}$ production in association with 1 and 2 hard jets. NLO K-factors nlo are applied to the Pythia results to avoid a normalization mismatch in the one-jet case. The mass spectrum is given by SPS1a, except for $\tilde{u}_{{L}}\tilde{u}_{{L}}$ where we reduced the gluino mass, as in Tab. \ref{['tab:njet']}. At high $p_T$ (of order the factorization scale and above), the matrix elements are, by definition, the most reliable while the parton showers can be seen to be associated with large uncertainties, whereas the opposite is the case at low $p_T$. The shaded region in the middle row is the theoretical uncertainty on the matrix element prediction. See text for details.
• Figure 2: The $\Delta R_{jj}$ distribution for $\tilde{g}\tilde{g} jj$ production as predicted by the hard matrix element and the parton showers.