Diffractive processes as a means to study new physics at the LHC

1. Diffractive processes as a means to study new physics at the LHC VAK, ADM, WJS and G.W., visit. profs: A.De Roeck, A.Kaidalov, M.Ryskin + 6 young int. scientists + FP-420 team membs Main aims: the theoretical motivations behind the recent proposals to add the Forward Proton taggers to the LHC experiments. the basic ingredients of Durham approach through the eyes of existing Tevatron and HERA diffractive data.  direct engagement with experimentalists in analysing and planning the forward measurements, in part., FP420 R&D. Theor. challenges :●need for the elaborated and well tested models for soft diffraction. ●unusually & uncomfortably large higher-order QCD eff. (e. g. Sud. and non-Sud. Logs… ). ● no suitable conventional analytic or MC results readily available (colour singl., Jz=0) .

2. Topics addressed so far • (25 published papers) • Higgs Huntingin the proton tagging mode.KKMRS- 00-06 • Various aspects of Diffractive Physics (soft & hard ) at the LHC.KKMR -00-01,05,06 • High intensity Gluon Factory at hadron colliders . KMR -00,01,02 • proton-proton luminometry at the LHC. KMOR-01 • photon-photon, photon - hadron physics at the LHC. KMR-02 • WBF mechanism of Higgs production with Rap. Gaps . DKMRO-02,KRSW-03 • Studies of the QCD & EW backgrounds to the H-> bb, WW signals. DKMOR-02, KRS-05, • CDKNPRST-05 • Central Exclusive Diffractive Production as a CP-parity analyser.KKMR-03, KMR-04. • ‘ Threshold Scan’ in the CEDP processes. KMR-02 • Exotics in the CEDP processes(‘invis’. Higgs, extra dim…)KMR-02, BKMR-04 • ‘ Standard candle’ processes at the Tevatron to test theor. predictionsKKMRS -01-05 • Tests of models fordiffraction at HERA. KKMR -01,03,06. • Diffraction of nuclei at high energiesKKMR-03 • FP taggingwould provide a unique additional tool to complement the conventionalstrategies at theLHCandILC.

3. The main advantages ofCED Higgs production • Prospects for high accuracy mass measurements • (irrespectively of the decay mode). • Quantum number filter/analyser. • ( 0++dominance ;C,P-even) • H ->bb opens up (Hbb- coupl.) • (gg)CED bb inLO ; NLO,NNLO, b- masseffects - controllable. • For some areas of the MSSM param. spaceCEDP may become adiscovery channel! • H→WW*/WW ()- an added value (Less challenging experimentally + small bgds.) • New run of the MSSM studies is underway (with G. Weiglein et al) • New leverage –proton momentum correlations (probes of QCD dynamics , CP- violation effects…) H  LHC : ‘after discovery stage’,Higgs ID…… How do we know what we’ve found? mass, spin, couplings to fermions and Gauge Bosons, invisible modes…  for all these purposes the CEDP will be particularly handy !

4. EXPERIMENTAL CHECKS OF DURHAM APPROACH • Up to now the diffractive production data are consistent with KKMRS results • Still more work to be done to constrain the uncertainties. • Very low rate of CED high-Et dijets, yield of Central Inelastic dijets. • ( CDF: Run I, Run II) data up to (Et)min>50 GeV. • ‘Factorization breaking’ between the effective diffractive structure functions measured at the Tevatron and HERA (CDF). • The ratio of high Et dijets in production with one and two rapidity gaps(CDF). • Preliminary CDF results on exclusive charmoniumCEDP. • Energy dependence of the Rap. Gap survival (D0, CDF) • CDP of γγ • Leading neutron spectra at HERA. BREAKING NEWS, CDF

5. S KMRS-05

6. Current projects and medium term (2006- 2008) plans • Comprehensive study of the radiative backgrounds to the H->bb CEDP, • application to the Higgs physics at PC@ILC. (KRS) • Leading neutron spectra at HERA as a way to gauge the absorptive effects • and enhanced Pomeron contributions (KMR) • Detailed investigation of the MSSM Higgs sector • in diffractive processes (S. Heinemeyer, M. Tasevsky, G. Weiglein + KRS) • Prospects to study the NMSSM Higgs in diffractive processes (A. De Roeck, • J. Gunion +KMR) • Study of the NLL- effects in the mass-suppressed Jz=0 gg/-> qq amplitudes (A. Shuvaev +KMRS +…)

7. 5 Higgsdiscovery in a Forward Proton mode PRELIMINARY Exclusion region S.Heinemeyer, V.A. Khoze, M. Ryskin, W.J.Stirling, M. Tesevsky and G. Weiglein in progress

8. Longer-term (2008-2010) plans. • VeryOptimistic scenario:FP-420 is approved, and Higgs is found at the LHC. • the meticulous work on improving the accuracy of calculations to match • the aimed for experimental precisions. • An interplay with a ILC. • + topics below. • FP420- unfriendly scenario: Higgs is found, but FP-420 is not approved or long delayed.  the application of the ‘event colour portrait’ technique (VAK&WJS et al.) to disentangle the Higgs signal from the QCD bgds. Using the developed calc. technique for the ILC physics: + topics below. • ‘Pessimistic’ scenario:ElementaryHiggs is not found and FP-420 is not approved. ●Comprehensive soft and semi-soft physics programs for TOTEM, CMS-TOTEM and ATLAS (possibly ALICE). Photon-induced interactions at the LHC. ●Top and stop studies revisited. ● Detailed (re) analysis of the Tevatron & HERA diffractive data for purely QCDpurposes. ● QCD studies at ILC.

9. First opportunity –autumn 2008(planned LHC shutdown)

10. FP420 is led by the UK. The physics case is led by Durham The New UK R&D Bid Close ties with Manchester and other UK FP 420’ ers. Successful annual IPPP-Manch. Forward wks (from 2001) Joint research and publications.