Prospects for standard SUSY searches at the LHC

The Large Hadron Collider with its ATLAS and CMS detectors will soon provide us with data to explore a new energy scale. Although already the very first data may contain surprises the first concluding results for the search for new physics are expected with the full 2009 data, where the LHC is expected to operate at √ s = 14 TeV. This article summarises the recent prospects for Supersymmetry (SUSY) with this data for the CMS and ATLAS experiments. In the majority of cases an integrated luminosity of 1fb−1 is assumed. Supersymmetry is one of the most favoured candidates for new physics. In this article we concentrate on the “standard” assumptions for SUSY, i.e. we assume that the R-parity quantum number is conserved. If this assumption is true, new SUSY particles would be produced in pairs and each decays into states which include the lightest SUSY particle (LSP). Other SUSY models (“non-standard”) are discussed elsewhere in these proceedings [1]. The LSP is only weakly interacting due to cosmological arguments and leads to the most characteristic feature of these SUSY events, missing transverse momentum. A general search strategy for standard SUSY signatures would be the selection of events with large missing transverse energy and reconstructed particles with large transverse momentum. At the LHC these objects are predominantly jets since the coupling strength of the strong force would cause an abundance of squarks and gluinos if these particles are not too heavy. Squarks or gluinos will cascade decay to jets, some number of leptons or photons depending on the SUSY parameters and missing transverse momentum caused by the LSPs. The searches for generic SUSY signatures with R-parity conservation are performed by searching for more events than expected in a countable number of different channels. These channels explore a large variety of possible signals, e.g. ATLAS studied various different jet (2,3,4) and lepton (0,1,2,3) multiplicities, channels with taus and photons [2]. CMS studied channels with jets and 0,1,2 leptons, 3 leptons, Z, top, photons or a Higgs boson[3]. The main challenge in these searches is to reliably control the Standard Model background expectations for our new experiments. In the following we assume mostly the 5-parameter mSUGRA as a “general” model for R-parity conserving SUSY. Both ATLAS and CMS have defined a set of benchmark points. We will show in the following examples for CMS point LM1 and for ATLAS point SU3. CMS point LM1 (m0 = 60 GeV, m1/2 = 250 GeV, tanβ = 10, A0 = 0 GeV, μ = +) has a cross section at 14 TeV of 55 pb and squark (gluino) masses of around 560 (610) GeV. ATLAS point SU3 (m0 = 100 GeV, m1/2 = 300 GeV, tanβ = 6, A0 = −300 GeV, μ = +) has a cross section at 14 TeV of 28 pb and squark (gluino) masses of around 630 (720) GeV. We will first present a ’discovery strategy’ based on inclusive searches for signals with missing transverse momentum and finally show examples of measurements of observables sensitive to model parameters.