Diffractive Higgs production Kaidalov,Khoze,Martin,Ryskin,Stirling Introduction SM Higgs pp  p + H + p Calculation of bb bar background 0 + and 0 - Higgs diffractive production SUSY Higgs diffractive production standard candles: excl.  jj prod. XVIIth Rencontre de Blois, May 2005 Alan Martin (IPPP,Durham)

pp  p + H + p 1

Double-diff ve exclusive Higgs production at the LHC The price for rapidity gaps ? 

no emission when  ~ 1/k t ) > (d ~ 1/Q t ) i.e. only emission with k t > Q t

calculated using detailed 2-channel eikonal global analysis of soft pp data S 2 = at LHC S 2 = 0.05 at Tevatron M H =120GeV Lonnblad Monte Carlo S 2 = S 2 = 0.040

Background to pp  p + (H  bb) + p signal LO (=0 if m b =0, forward protons) gg  gg mimics gg  bb (P(g/b)=1%) after polar angle cut 0.2 |J z |=2 admixture (non-forward protons) 0.25 m b 2 /E T 2 contribution 0.2 HO (gg) col.sing  bb+ng Still suppressed for soft emissions. Hard emissions if g not seen: extra gluon along beam M miss > M bb  0 extra g from initial g along b or b bar 0.2 Pom-Pom inel. prod. B/S<0.5(  M bb /M PP ) 2 <0.004 B/S Total B/S~1 assuming  M miss ~3 GeV DKMOR

First level trigger ? Two E T >50 GeV jets + collinearity + “gapiness” ?

higgs pp  p 1 + higgs + p 2

rescatt. corr. omitted S 2 =1

p 1T,p 2T correlations reflect spin-parity of central system: can distinguish 0 - from 0 + pp  p 1 + H + p 2 more peripheral

decoupling regime: m A ~ m H large h = SM intense coup: m h ~ m A ~ m H ,WW.. coup. suppressed

e.g. m A = 130 GeV, tan  = 50 (difficult for conventional detection, but exclusive diffractive favourable) S B m h = GeV events m H = GeV m A = 130 GeV 1 5 SM: pp  p + (H  bb) + p S/B~10/10~1 with  M = 3 GeV, at LHC with 30 fb -1 enhancement

30 fb fb -1 5  signal at LHC

Br.  in (fb) for H 1, H 2, H 3 production at the LHC S/B~M -5 cuts: (a) MeV, (c) 45<  (b)<135 0 fb

Allow p’s to dissociate Larger signal---but no  QCD (bb) suppression, so use H 1    (…) E iT >7 GeV 1 + a sin 2  b cos 2  if CP cons. then a=0, |b|=1  p 1T p 2T fb

“standard candles” Possible checks of exclusive rates at the Tevatron

ExHuME Monte Carlo - direct implementation of KMR J. Monk and A. Pilkington, hep-ph/ Plot from B.Cox and A. Pilkington, to be published exclusive ExHuME POMWIG CDF data

(KMRS ~ 1pb) M.Gallinaro (hep-ph/ ) Limits on exclusive (CDF) dijet production

Diffractive  production KMR+Stirling only order-of-magnitude estimates possible for  production

pp  p +  + p KMR+Stirling

Conclusions Proton tagging is a valuable weapon in LHC Higgs physics pp  p + (H  bb) + p: S/B~1 if  M miss ~3 GeV, M miss = M bb especially for the important M H < 130 GeV region SUSY Higgs: unique signals in certain domains of MSSM tan  large (i) m h ~m H ~m A (  enhanced), (ii) m A large Azimuthal correlations are valuable spin-parity analyzer Distinguish 0 -- from 0 + Higgs “standard candles” at Tevatron to test excl. prod. mechanism pp  p +  + p high rate, but only an ord.-of-mag.estimate pp  p + jj + p rate OK, but excl. evts have to be separated pp  p +  + p low rate, but cleaner signal Exclusive double diff. prod. strongly favours 0 + Possibility of detecting CP-violating Higgs

H1 MRW CDF dijet data rapidity gap survival prob. **