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MHV Rules, Supersymmetry, and 'Diffractive Higgs' at the LHC

This study focuses on applying MHV rules and supersymmetry in the forward proton mode to study 'diffractive Higgs' production at the LHC and understand major QCD backgrounds. It aims to determine the Higgs mass, study the Higgs sector, and explore non-pile-up backgrounds for Higgs production.

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MHV Rules, Supersymmetry, and 'Diffractive Higgs' at the LHC

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  1. MHV rule, supersymmetry and ‘Diffractive Higgs’ V.A. Khoze (IPPP, Durham) Main aims•MHV rules and SUSY at the service of ‘diffractive Higgs’ •major QCD backgrounds to Hbb production at the LHC in the forward proton mode (based on works with M.G. Ryskin, A.D. Martin and W.J. Stirling) (J.Forshaw, M.Tasevsky, A.De Roeck) Higgs sector study- one of the central targets of FP420 physics menu

  2. For theoretical audience For experimental audience MHV rules, Super (symmetry) and ‘Diffractive Higgs’ at the LHC Non- Pile-Up Backgrounds to Diffractive Higgs Production at the LHC • Forward Proton Mode- Main Advantages: • •Measurement of the Higgs mass via the missing mass technique (irrespectively of the decay channel) • •Direct H bb mode opens up (Hbb Yukawa coupling); • unique signature for the MSSM Higgs sector. • •Quantum number/CPfilter/analyzer • •Cleanness of the events in the central detectors. (J. Forshaw, M. Tasevsky, A. De Roeck)

  3. without ‘clever hardware’: for H(SM)bb at 60fb-1 only a handful of events due to severe exp. cuts and low efficiencies, though S/B~1 but H->WWmode at M>135 GeV MSSM situation in the MSSM is very different from the SM > Conventionally due to overwhelming QCD backgrounds, the direct measurement of Hbb is hopeless The backgrounds to the diffractive H bb mode are manageable but should be studied very thoroughly !

  4. (J. Forshaw) new CDF result (between Scylla and Charybdis)

  5. (K. Goulianos) d

  6. for Higgs searches in the forward proton modeQCDbackgrounds are suppressed by Jz=0 selection rule and by colour, spin and mass resolution (M/M) –factors. There must be a god

  7. certain regions of the MSSM parameter space are especiallyproton tagging friendly (at large tan  and M , S/B ) KKMR-04,HKRSTW-07 Myths For the channelbgds are well known and incorporated in the MCs: Exclusive LO - production (mass-suppressed) + gg misident+ soft & hard PP collisions. Reality The complete background calculations are still in progress (uncomfortably & unusuallylarge high-order QCD and b-quark mass effects). About a dozen various sources (studied by Durham group)  admixture of |Jz|=2 production.  NLO radiative contributions (hard blob and screened gluons)  NLLO one-loop box diagram (mass- unsuppressed, cut-non-reconstructible)  b-quark mass effects in dijet events – still incomplete potentially, the largest source of uncertainties!

  8. (S .Parke, T.Taylor (1986))

  9. (CFCA)

  10. (+ n soft gluons)

  11. mb=0

  12. beam direction case if a gluon jet is to go unobserved outside the CD or FD ( ) • violation of the equality : (limited bythe ) contribution is smaller than the admixture of Jz=2. KRS-06 b-direction case (HCA) 0.2 ( R/0.5)² (R –separation cone size) Note :  soft radiation factorizes strongly suppressed is not a problem,  NLLO bgd numerically small  radiation from the screening gluon with pt~Qt: KMR-02 HC (Jz=2) LO ampt. ~ numerically very small  hard radiation - power suppressed MHV results for gg(Jz=0)ng amplitudes (dijet calibration, b-mistag)

  13. Approximate formula for the background main uncertn. at low masses M- mass window over which we collect the signal b-jet angular cut : ( ) bothSand Bshould be multiplied by the overall ‘efficiency’ factor (combined effects of triggers, acceptances, exp. cuts, tagging efficienc., ….),  ~4.2 % (120 GeV)  g/b- misident. prob.P(g/b)=1.3% (ATLAS) Four major bgd sources ~(1/4 +1/4 + (1.3)²/4 + 1/2 ) at M≈120 GeV, M= 4GeV

  14. Conclusion Strongly suppressed and controllable QCD backgrounds in the forward proton mode provide a potential for direct determination of the Hbb Yukawa coupling and for probing Higgs CP properties. Invarious MSSMscenariospp p +(Hbb)+pmay become a discovery channelat the LHC. Further bgd reduction may be achieved by experimental improvements, better accounting for the kinematical constraints, correlations….. The complete background calculation is still in progress (unusually & uncomfortably large high-order QCD effects, Pile-Up at high lumi) (M.Tasevsky) Further theoretical & MC and experimental studies are needed

  15. (M. Tasevsky & HKRSW )

  16. BACKUP

  17. PRELIMINARY (M. Tasevsky & HKRSW )

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