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Stefano Moretti (Southampton & RAL)

Uppsala, 16 September 2006. Summary of conclusions: phenomenology and MC generators. Stefano Moretti (Southampton & RAL). A charged Higgs signal (unlike a neutral one) is always a signal of (whatever) BSM physics !. For example in the MSSM, once a Cinderella now:.

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Stefano Moretti (Southampton & RAL)

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  1. Uppsala, 16 September 2006 Summary of conclusions: phenomenology and MC generators Stefano Moretti (Southampton & RAL)

  2. A charged Higgs signal (unlike a neutral one) is always a signal of (whatever) BSM physics ! For example in the MSSM, once a Cinderella now:

  3. MC@NLO for pp->tH(->tau-nu) ? Analyses use NLOfullyinclusive K-factors Main background fromttexists in MC@NLO, we are very close to it for the signal !

  4. SUSY virtual effects In Yukawa vertex – they are detectable ! (Also, survive in decoupled SUSY.)

  5. One-loop diagrams in Higgs-W associated production: They can significantly increase the cross section (light sparticles)

  6. And WH channel may well be feasible ! Note: no SUSY enhancement exploited here !

  7. SUSY & Higgs interplay If SUSY kinematically accessible, then real production of sparticles: • Higgses can decay directly to or come from decays of SUSY particles • Associated production modes: eg, squark-squark-Higgs • SUSY particles suppress or enhance loop induced production or decays Higgs into sparticle decay modes can compete with SM modes Further source of Higges from cascade decays of heavy SUSY particles, in fact Squarks & Gluinos can give many more Higgses than direct production ! “little cascade from neutralinos/charginos” “big cascade from neutralinos/charginos”

  8. Useful for filling MSSM decoupling region: eg, SUSY  Higgs. M_2=175 GeV, M_2=350 GeV, mu=150 GeV, M_{slep}=175 GeV, M_{sq, gluino}= 800 GeV

  9. Useful for filling MSSM decoupling region: eg, Higgs  SUSY. M(2)=180 GeV, mu=-500 GeV, m(all sleptons)=250 GeV, M(squark,gluino)=1 TeV * Philosophy so far: scan parameter space to optimise leptonic signals (easiest) * Discovery areas for different channels correspond to different SUSY configurations * Problem: discovery plots cannot be superimposed(what’s true LHC potential ?) * Alternatively: adopt SUSY Higgs benchmark points (a la SPS, LHC points, etc.)

  10. SUSY benchmark points in mA tan  plane 4 8 7 h,A,H,H h,A,H h,H 1a h (SM -like) H,H h,H h,H h,H,H h,A,H,H • Require dedicated study to give suitable set of benchmark points Snowmass points and slopes: SPS hep-ph/0202233 Chosen with SUSY space rather than Higgs space in mind. 9 points: 5+1 mSugra, 2 GSMB, 1 AMSB Only 4 points feature in usual Higgs plane. 1a, 4 (mSUGRA) 7,8 GMSB. Benchmarks from Carena et al. Eur. Phys. J. C 26 601 (2003) not designed to take light SUSY particle effects into account, except in stop loops (gluo-phobic Higgs scenario)

  11. Tools (other than std MCs: PYTHIA, HERWIG, ISAJET)

  12. SMadGraph/SMadEvent includes charged Higgs in THDMs,MSSM • Battleground • general-purpose: user can pick & mix plus all irr. bkgd implemented but slow/inefficient esp.in PS opt.n • dedicated: fast/efficient but list of processes fixed (authors priorities may not comply with users’ needs) • By experience (LEP2, largely Tevatron too) dedicated ones win favour of the exp. Collaborations, • one (very personal) question: is it possible to automatise `Forest & Groves’ (minimal G.I. structures) and drop useless bits of codes ? Issue:

  13. Most include PS matching (ad hoc or via LH accord) • Important: • To understand whether differences are genuine – stem from physics differencesin matching procedures or are bugs ? • 2) Validate against data: not only jet kinematics but also hadronic distributions inside jets (treatment of subleading colour structure in matching for high multeplicities)

  14. Tasks from this workshop General consensus emerged on the importance of a full MC@NLO analysis of bg->tH(->tau-nu) & (dominant) tt background: Tilman to consider MC@NLO implementation of signal with Johan^2’s help SM was volunteered by Tord to setup `task force’ to generate Uppsala Points to study SUSY effects in charged Higgs searches atTevatron/LHC Johan and Stefan agreed to implant PS & Hadr.n onto their WH(->tau- nu) analysis, ATLAS & CMS very attentive and interested to run a fast detector simulation if full MC analysis points to feasibility – it will be probably a complementary handle for accessing covered MSSM regions Yann volunteered to look at bg  tW and see whether there is any potential at Tevatron (may need lumi well in excess of current fb) in testing bg->tH (very large tan(beta) only) and/or ME/PS matching

  15. Outlook • Tord: there are enough tasks already assigned here to run cHarged 2007 to check that the homework has been done ! • Besides, Uppsala is pretty, people are welcoming, loved the ethanol stuff last night … • … and you are quite a character (must say) ! • In fact, thanks to all the organisers for a very enjoyable workshop !

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