ATLAS physics studies

Higgs searches

We are working on the detection and measurement of the properties of light Higgs boson signals predicted in the context of various models. Past projects include the determination of the CP-parity of a Higgs particle using the ttH (H->γγ) channel, and the detection of an invisible Higgs produced in association with a pair of top quarks. Current projects have focused on the ttH (H->WW) signature. We are also involved in the ATLAS Statistics Committee which, among other things, provides guidance for the combination of various Higgs analyses, with the aim of maximizing an early Higgs discovery.

Supersymmetry searches

We are searching for supersymmetric signatures with special regard to dilepton final states.  We are developing data-driven methods to estimate the background from ttbar events, and also investigating use of multivariate methods to enhance the expected discovery significance.

Exotic searches

We are interested in looking for exotic phenomena; for example signs of extra dimensions, which could provide an explanation for the weakness of gravity. Current projects involve looking for a graviton in the 4 lepton channel (G->ZZ->4l).We also have an interest in using exotics' signatures as benchmarks for detector and trigger physics performance, with particular regard to high-pT electron/photon signatures.

QCD and statistics

A good understanding of parton densities is vital at a proton-proton collider like the LHC. We are developing alternative techniques for quantifying the effect of uncertainties in parton densities based on a Bayesian approach.

Top quark

Top quark physics is crucial for establishing Standard Model physics in the commissioning phase of ATLAS. Also, due to its large mass, the top quark will be sensitive to new physics involved in the electroweak symmetry breaking mechanism. Current projects involve measuring the top pair cross section using early data (~100 pb-1).