-- TomRavenscroft - 2012-01-20

Summary Of ATLAS UK Work

This page summaries other ATLAS UK groups work in Higgs analysis, taken from web pages and also presentations made at the ATLAS UK meeting 2012.

Alphabetical List of Groups

University of Birmingham

Involved in search for low mass Higgs in H -> bb searches from either W or Z bosons.

They presented work at ATLAS UK 2012 in conjuntion with Liverpool on seaches for Higgs in VH channel with V being either vector boson. The analysis was done in the three major channels: WH -> l\nubb, ZH -> llbb and ZH -> \nu\nu.

They used the full 2011 data set. and identified major backgrounds in the data as: W/Z+jets, tops, QCD, diboson and high WH stats.

Selection of the ojects wa split into groups for different criteria. For single elctrons they had to have pT > 25(20)GeV for W(Z -> ll), |\eta| < 2.47, a strack isolation of < 0.1 and \DeltaR < 0.2. The impact parameter, d0 < 0.1mm.

For single muons, the pT, track isolation, \DeltaR and |\eta| < 2.47 was the same as for electrons but the impact parameters were z0 < 10mm and d0 <0.1(1)mm for W(Z -> ll).

There was no singnificat excess in any of the mentioned channels. The WH limits have not yet been completed but the yare expected to be comparable to the ZH limits, giving a combined VH (H -> bb) limit.

There is good MC data agreement and will publich an inclusive VH analysis contributing to the standard model Higgs combination. BirminghamATLAS

University of Edinburgh

Involved with search for the Higgs in WH (H -> bb) and H -> ZZ(*) -> 4l channels. Not much information on their website.

Heavily involved with working with UCL in a boosted Higgs analysis of WH and ZH presenting preliminary results at ATLAS UK 2012 meeting where they showed only the analysis for WH -> l\nubb. (ZH analyses are still being developed). Although they are working closely together, UCL and Edinburgh have independent analysis codes.

Working on a neural network approach in parallel to this an attempt to improve the sensitivity. Also planning a data-driven QCD. EdinburghATLAS

University of Lancaster

Working on Higgs decays to leptons is all it says about Higgs searches. They have done work on B-physics, looking for new particles decaying in to top quarks and also J/ \Psi decays to understand triggers. LancasterATLAS

University of Liverpool

Liverpool is involved with a number of Higgs analyses in a number of channels: H -> ZZ( * ) -> 4l, H -> ZZ( * ) -> 2l2b, ZH -> 2l2b and H -> \tau\tau.

As stated higher up, presented work alongside Birmingham on VH (H -> bb) decays. Liverpool also presented their work on H -> ZZ -> ll\nu\nu/llqq analysis.for a high mass Higgs candidate, allowing for the testing for many Higgs theories. Their search was done over the entire data set with backgrounds in Z/W+jets, Top, Diboson and QCD. They will publish a paper on the full 2011 analysis before extending the search up to a 600GeV candidate. Liverpool will continue theire H -> ZZ -> \nu\nubb channel and set limits on the non-standard model Higgs. LiverpoolATLAS

University of Manchester

Nothing indepth at all, but does state they are working on charged Higgs searches in top decays. Manchester ATLAS

University of Oxford

H -> WW and H -> \tau\tau searches as well as beyond the standard model Higgs searches. No extra information. OxfordATLAS

Queen Mary University of London (QMUL)

Studying Top quark production and mass as well as Higgs production in H -> WW channel. and any deviatoins from the standard model. QMUL_ATLAS

Rutherford Appleton Lab (RAL)

Involved with B-physics emphasising on triggering , W-physics on the W cross-section measurements, mass and decays. Higgs searches include ttH and H -> \gamma\gamma. RAL_ATLAS

Royal Holloway University of London

Areas of Higgs study include ttH -> \gamma\gamma and ttH -> WW. Investigting the physics of inclusive and exclusive SUSY signatures as well as looking for exotic phenomena (extra dimensions) RoyalHollowayATLAS

University of Sheffield

The Sheffield group have Higgs searches in a four lepton decay channel in association with the production of a pair of Z Bosons. There is also work on H -> \gamma\gamma process.

At ATLAS UK meeting there was work presented on the H -> ZZ -> 4l channel. They used 4.8 pb-1 of data in the analysis, but have a draft for a Conf. note for 4.8 fb-1. Currently the renormalisation of the ZZ relies on MC. SheffieldATLAS

University of Sussex

Looking for evidence of neutralino by looking for large missing energies as well as other leptonic supersymmetric partners SussexATLAS

University College London (UCL)

Searching for the Higgs but does not say in which channels on their website. They have a contribution to the trigger and the recording of events.

At the ATLAS UK meeting 2012, Edinburgh had a presentation on boosted Higgs analysis in conjuntion with UCL in WH and ZH. The Boosted Higgs analysis was well underway for Z -> bb at UCl with an expected constraint on WH/ZH systematics. UCL_ATLAS

Useful Links

Latest SM Higgs Results here

Seminar regarding latest results (Dec 2011) here

ATLAS UK 2012 Higgs presentations here