1 / 17

Higgs associated production at L H C :

Higgs associated production at L H C :. The. case. Olivier Ravat , Morgan Lethuillier IPN Lyon. Les Houches 2003 : Physics at TeV Colliders. Production at L H C. Small NLO Corrections: According to V2HV (M.Spira) a K factor of 1.3 can be applied. σ (pb). NLO LO. MH.

zeph-ruiz
Télécharger la présentation

Higgs associated production at L H C :

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Higgs associated production at LHC : The case Olivier Ravat, Morgan Lethuillier IPN Lyon Les Houches 2003 : Physics at TeV Colliders Les Houches/June 3rd 2003

  2. Production at LHC Small NLO Corrections: According to V2HV (M.Spira) a K factor of 1.3 can be applied. σ (pb) NLO LO MH Les Houches/June 3rd 2003

  3. The pp lνγγchannel Signature :2 hard photonsreconstructing to the Higgs mass 1 charged leptonandmissing PT Processes with such a final state : Signal Les Houches/June 3rd 2003

  4. Motivations • This channel is far cleaner than the usual H γγ. Less dependant on calorimeter resolution. • Vertex reconstruction is easy, thanks to the charged lepton better measurement of MH • Increases the coverage of MSSM(MA,tgβ) parameter space (D.Denegri, R.Kinnunen CMS-NOTE 96-091); interesting for the 2HDM(I). • History : A study has been performed in 1997 at the generator level (M.Dubinin et Al. CMS NOTE 1997/101) and we would like to update the study with a detector simulation. Les Houches/June 3rd 2003

  5. Generation of the physics events • MH = 120 GeV • Structure function: CTEQ 5L • Signal generatedwithPythia 6.2andCompHEP 41.10in order to perform some cross-checks, • Backgrounds generated with CompHEP 41.10 Les Houches/June 3rd 2003

  6. Cross-sections of signal and irreducible background Total NLO cross-section for WH production : 2 pb In order to assure an efficient production we imposed some generator level cuts : Les Houches/June 3rd 2003

  7. Kinematics for the signal, Pythia and CompHEP Pythia CompHEP Pythia CompHEP Pythia CompHEP Pythia CompHEP Les Houches/June 3rd 2003

  8. Kinematics for the signal, Pythia and CompHEP Pythia CompHEP Pythia CompHEP Les Houches/June 3rd 2003

  9. From CompHEP 4-vectors to a simulated final state • Using cpyth_for_CMSIM (A. Sherstnev) : hadronization and fragmentation with Pythia. • Output : HEPEVT ntuple compatible with CMSJET and CMSIM. • Pythia tuned to fit the underlying event and the minimum bias using the CDF data, then extrapolation to LHC energies. Les Houches/June 3rd 2003

  10. Tuning Pythia parameters (Rick Field settings) Les Houches/June 3rd 2003

  11. CMSJET parameters 30 MeV Noise in the ECAL barrel : Noise in the ECAL endcaps: 0.5% of dead cells. 150 MeV 0.5% pT cut for photons : 20 GeV pT cut for electron : 20 GeV pT cut for muon : 10 GeV Les Houches/June 3rd 2003

  12. CMSJET parameters No charged particle with in a cone ΔR =0.3 around leptons and photons. No cluster with more than in the calorimeters around leptons and photons. Number of selected eventsfor 1 year at HL: pT>2 GeV ΔR =0.3 5 GeV Signal : 14 Background : 214 Les Houches/June 3rd 2003

  13. Results with ~17.3 events/bunch crossing CMS : 100 fb-1 CMS : 100 fb-1 Les Houches/June 3rd 2003

  14. Results with ~17.3 events/bunch crossing CMS : 100 fb-1 CMS : 100 fb-1 Cut Cut Les Houches/June 3rd 2003

  15. Results with ~17.3 events/bunch crossing After one year at high luminosity, cuts of 55 GeV on the hard photon and 30 GeV on the soft one : CMS : 100 fb-1 In a mass window of 118.6<Mγγ<121.4 we get Nice, but does not yet include reducible background… Les Houches/June 3rd 2003

  16. Conclusions and perspectives The WHlνγγ channel can hardly be considered as a discovery channel but it’s very clean (almost free from background!) It also allows a more precise measurement of MH : the charged lepton kills the pointing contribution on ΔMH; It would be a “rescue channel” in case of maximal stop mixing. Les Houches/June 3rd 2003

  17. What’s next? The processing of 4-vectors with CMSIM is on its way in view of full simulation and reconstruction with ORCA. The generation of the ZH and ttH cases is performed both for signal and background (analysis still to be done). Reducible backgrounds are being produced Les Houches/June 3rd 2003

More Related