Production of Two Vector Bosons, especially Diffractive

1. Production of Two Vector Bosons, especially Diffractive •  Standard Model direct (non-Higgs, top) VV Production • Higgs Production and Decay  VV, especially DPE • Related Processes at Tevatron • VV at the LHC ... importance of pots. • Introduction to “White Pomeron” … next talk by Alan White

2. S.M. Diagrams for Prompt VV Pair Production in pp/ppbar (Prompt i.e. not from top decay and not from Higgs) [(e) is not S.M., sorry!] • Note different color flows in these • diagrams  can give different • hadronic activity. • and (b) have color 3 annihilation • (d) has color 8 annihilation • (c) and (e) have color singlet exchange. • (c) high pT q – forward jets; (e) low pT p’s – no jets, can be exclusive

3. Cross section for WW Production: Energy Dependence Tevatron cross section agrees with CTEQ NLO Tev WW~12.4 pb, ZZ ~ 1.4 pb LHC ~ 10 x higher WW~ 130 pb; ZZ ~ 20 pb BR WW  e/mu = 4.5% How many SD? In 10fb-1 ~ 600 if “RoT” Clean, single? L(opt) ~ 4E32 (<n> = 1/x) How many DPE? RoT  ~ 60 (not exclusive) These need to be simulated

4. Note value of MM in DPE events with Branching Fractions for VV

5. WW, WZ and ZZ Searches in CDF and D0 Run 1: CDF observed 5 WW candidates. Phys.Rev.Lett 78 (1997) 4356. (CDFNOTE–3673) in good agreement with SM-NLO Run 1: D0 observed 5 WW candidates. Phys.Rev.D58 (1998) 051101 Run 2: D0 observe 25 WW candidates, BG(est) ~ 8. hep-ex/0410066 Run 2: CDF observes 17(32) WW candidates, BG(est) ~ 5(12) (CDFNOTE-7255) (17 events) Run 2: CDF observes 3 WZ+ZZ candidates, BG(est) ~ 1.0 +- 0.2 (CDFNOTE-6920) 2 events are common to both searches (WW/ZZ ambiguous) Consistent with NLO theory (Campbell & Ellis):

6. WW Production (also WZ, ZZ) CDF-6909 Paper in draft 10% 90% fakes

7. W,Z + high pT photon + inner brems CDF: PRL(subm 9/04)

8. Photon-Photon Mass Spectrum Looser cuts to search for “bumps”

9. SM Higgs Production at the Tevatron and Decay 170 GeV non-H is continuum H is peak (width ~ 0.4 GeV) But have poor mass resolution (NB Missing Mass method for exclusive pp  pHp) (H) x acc. x eff.

10. SM Higgs at the LHC Just H  VV S.Dawson Signal “localized” but WW mass resolution poor MSSM can be > 100 x bigger

11. Exclusive Higgs Production by Double Pomeron Exchange •  Can be inclusive (soft central hadrons) but exclusive (nothing else) • most interesting. Precision measurement of both p  M(central) by MM • Possible resolutions ~ 250 MeV at Tevatron, ~ 2-3 GeV at LHC. •  Can go for dominant H(110-130) b-bbar decay mode •  Exclusive DPE  q-qbar dijets strongly suppressed (Jz = 0 rule) •  Selection Rule on central Q.Nos: •  pp Correlations tell Q.Nos  scalar (need statistics!) •  Tevatron too low for SM H • LHC possible (but difficult) • Non-SM H very interesting! (KMR=Khoze, Martin, Ryskin)

12. Relevant studies we are doing in CDF: DPE Exclusive is gold-plated DPE Inclusive is also interesting, but “no” Missing Mass Non-SI channels to compare for associated event structure or unusual extremes of activity

13. CDF Detectors em + had cals, muons MiniPlugs

14. Demonstrating a diffractive signature generally means showing a distribution with 2 components, classically a peak in a distribution not well fit by the bulk or a control sample. CDF Diffractive W production D0: Diffractive W & Z D0 Diff W,Z PL B 574 (2003) 169 (a) central W (b) forward W (c) Z CDF Diff W PRL 78 (1997) 2698 BBC counter multiplicity ~ 1% (Andrew Brandt: Different definitions)

15. Other diffractive discoveries The signal may be more striking, and be in more than 1-dimension, as in D0 W/Z plots & CDF DPE  di-jets (PRL 85 (2000) 4215) But it need not be a gap signature, Feynman-x is good as in discovery of high mass diffraction at ISR. High-x peak is distinct class. (High x_F correlates with big gap) 0.95

16. Is there any evidence for a diffractive component, or anomalous high or low activity, in different rapidity regions (forward, central, both) in events with two vector bosons? (Color Singlet High pT objects) Many variables In CDF: (look for distinct peak in n-dimensions) Most cannot be used in the presence of pile-up Compare between channels, compare to tuned MC’s, study tails of distributions

17. Event B: ZZ  4e Candidate R/E 147806/1167222 Note: Cannot detect smaller polar angle tracks Good ZZ(4e) candidate except 1 e just fails ISO cut (so excluded from x-sn limit) Exceptionally active event How unusual is that? Is it > 1 interaction? Low – b ?

18. Event C: WW  ev ev Candidate R/E 165906/1741744 • Cleanest event in sample • also in E & W forward detectors. • 2 tracks in R-phi view dissociated • or badly measured? • Other 2 < 400 MeV/c also very small (of course) High-b?

19. Central Exclusive WW Production at LHC Nothing else on 2-lepton vertex! e + White Pomeron & other BSM search & if single interaction (L <~ 4.10^32) ~ empty detector + p’s … but need to study signal with pile-up.

20. At Tevatron of course see if roman pot sees the p/p-bar (Roman pots are read out for every event) - important

21. Double (White) Pomeron  W+W- via Q6 Loop • Photon-Pomeron-Z vertex • via Q6 loop. LHC? • also ep (eg LC+p (Tev,HERA,LHC)) could be very interesting!

22. Closing Thoughts: CDF(/D0?) data with 200 pb^-1 do not show a significant anomaly in WW/ZZ production. Will get ~ 25 x more data WW/WZ/ZZ are very interesting channels, sensitive to new physics, whether there is a Higgs or not. Possibly dramatic effects at LHC, long shot at Tevatron. Need to simulate exclusive channels, also with pile-up. Central Exclusive Production likely to be very exciting at LHC.