Higgs production with forward protons Pomwig v2.0 Manchester, Dec. 2003

1. Pomwig New extensions Towards a physics case for DPE Future additions Higgs production with forward protonsPomwig v2.0Manchester, Dec. 2003 M.Boonekamp, T.Kucs M.Boonekamp - Manchester, Dec.2003

2. Process studied since beginning of 90’s : many groups, many models (some of them complementary, e.g. incexc), large variety of predictions Meanwhile : much experimental interest, since it was realized (Albrow, Rostovtsev) that Missing Mass measurements would provide extraordinary mass resolution at the Tevatron. LHC study performed since then (Finland group): Forward proton detector setup : complicated interplay 3-4 more years before LHC start-up Physics case still to be made : Given (Tevatron data){ if (Exc IsLargeEnough) return 0; else if (Inc IsLargeEnough) return 0; else return 1; } Very few Monte-Carlo programs : Pomwig ( Herwig), SCI ( Pythia) Situation x1 Triggerable sM x1 = M2/(x2s) x2 M.Boonekamp - Manchester, Dec.2003

3. Models QCD, Exclusive QCD, Inclusive, Non Factorized p p B) A) X X p p QED, Exclusive QCD, Inclusive, Factorized p p,A C) D) X X p p,A M.Boonekamp - Manchester, Dec.2003

4. Models A X • Topology • 2 outgoing protons + hard central system ; large rapidity gaps ; QCD mediated • A few hints on phenomenology • Process is hypothetical but a potential jackpot; wide range of predictions • Model A-1 : Bialas-Landshoff (Regge-inspired, non-perturbative) : sH~ 100 fb (disf.) • Model A-2 : Khoze, Martin, Ryskin (Entirely perturbative) : sH~ 3 fb • Experimental remarks (relevant for LHC) • H mass range bounded by xminxmins • Mass resolution down to 1% (  Helsinki best case) • s/b : H  bb / bb continuum O(1), thanks to several suppression mechanisms (central system has Jz=0, is color singlet) M.Boonekamp - Manchester, Dec.2003

5. Models B&C X X • Topology • 2 outgoing protons + hard central system + Pomeron remnants • Small, very forward (undetectable, if mX large) rapidity gaps • A few hints on phenomenology • Process exists (  is being measured) and is fairly large ; sH ~ 100-300 fb • Model B : Boonekamp-Peschanski-Royon, extension of the original (exclusive) Bialas-Landshoff model. • Model C : Cox-Forshaw; factorization assumes Hera fluxes (Pomwig) • Experimental remarks (relevant for LHC) • Can go below xminxmins : window to low Higgs masses at LHC? • Any improved mass reconstruction relies on Pomeron remnants detection • s/b : H  bb / bb continuum O(10-3-10-4) H  tt / tt continuum O(10-1-1) M.Boonekamp - Manchester, Dec.2003

6. Models D X • Topology • 2 outgoing protons + a hard central system ; QED mediated • Summary on phenomenology • Process exists, is small in pp (sH ~ 0.3 fb) large in e.g. Ca-Ca(sH ~ 10 pb), Pb-Pb(sH ~ 100 pb) • Model D-1 : pp; usual proton EM form factor; b-space (Papageorgiu, Cahn-Jackson) • Model D-2 : AA, Gaussian form factor (Cahn-Jackson, Dress-Ellis-Zeppenfeld) • Remarks • H mass range bounded by xminxmins in pp • No proton tagging in heavy-ion collisions • D-1 : long term spin-parity determination? • D-2 : Luminosity too small for Lead-Lead, possible try in Ca-Ca mode • s/b as in A), O(1) M.Boonekamp - Manchester, Dec.2003

7. Pomwig • Very few models have a Monte-Carlo incarnation (only the Factorized Inclusive, and Soft Color Interaction models as far as I know) • Pomwig v.1 : extension to Herwig, by Cox & Forshaw (model B). Uses : by a proper reweighting of the photon flux, and an adapted choice of the structure functions • Single & Double Diffraction e+ to simulate e- M.Boonekamp - Manchester, Dec.2003

8. Pomwig v2.0 • It turns out that the factorized e+e-  e+e- hadrons machinery of Herwig can be used to parametrize a lot of models, including the non-factorizable ones • We generalized the approach to our model (model B) • Other additions: • Exclusive DPE à la Bialas-Landshoff (model A) • QED diffraction as well (proton-proton and heavy-ion mode; models D) • Profits from the many hard subprocesses available via Herwig • New processes : gg  H ; Jz=0 gg  qq, gg  gg, gg  qq • Will appear soon on hep-ph (note/manual) and pomwig.com (source code) M.Boonekamp - Manchester, Dec.2003

9. Pomwig v.2 p-induced P (R) flux p-induced g flux Ca-induced g flux • Regge parameters (P/R trajectories) tunable • g fluxes : Z, A, bmin settable M.Boonekamp - Manchester, Dec.2003

10. Pomwig v.2 : dijets (pT>20 GeV) * Caveat : does not contain factor ~4 enhancement from comparison to CDF Run1 DPE dijets BPR all * BPR bb * BL bb M.Boonekamp - Manchester, Dec.2003

11. Pomwig v2.0 : Higgs bosons * Caveat : does not contain factor ~4 enhancement from comparison to CDF Run1 DPE dijets } BL BPR * DPE CF Papageorgiu gg M.Boonekamp - Manchester, Dec.2003

12. Pomwig v2.0 : Settings gg / gg Model Process M.Boonekamp - Manchester, Dec.2003

13. Pomwig v2.0 : Perspectives • Important : KMR model missing Not so trivial : one (numerical) QT integration at every phase space point First order approx : use rescaled BL prediction (but x dependence?) • gg c, b process and interface to exclusive & inclusive production M.Boonekamp - Manchester, Dec.2003

14. Studies to be performed ( Physics case) • Inclusive models : Determination of Regge parameters on forthcoming Run2 CDF and D0 data  Predictions at the LHC : does any channel have a chance (tt? low mass?) • Exclusive models : perform analysis at hadron/detector level Take background from Inclusive production as found above • Exclusive tt channel (lepton/hadron trigger) • Worst case : exclusive given by gg exchange  do we still see something? (surely no discovery, maybe spin/parity in the long term?) • L1 trigger with central detectors : large gaps can save us : find Lopt, and request it # # ~ L s #.P(1 int) Lopt ~ few 1033? M.Boonekamp - Manchester, Dec.2003 L