level 1 50 kHz max rate

lhc … 4 sigma h->gamma gamma => 3 sigma in diffractive channel

Issue of diffractive Higgs quite a triumph for IPPP.  Idea from experiment… differing theory… workshop… consensus… plan of action.

LEP2 limit ~ 40 MeV       Systematics energy scale, radiative corrections, will hit sys. limit in run 2 Main sys on MW theoretical (pdf, pt(W), qcd h.o. corrections).. 30 MeV (better prediction than run 1; 75 MeV) Pdf main systemtatic (25 MeV, to reduce must raise min MT(W) used for fitting .. this is most sensitive to it)

run 2: 34 MeV in common in total error. 25 MeV due to pdf

The sort of event that di-photon search is sensitive to

quark annihliation dominant, gluon will be for LHC.  Show diagrams and cross-sections.

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Note 1:1 S/B.  Description of bkg req’d. A bkg which peaks at or about top mass…. Need W+4jet to be good

Even more bkg

Clean but no stats…  note numbers of final states…

New physics:  top been produced in non standard way; top decaying non standard

The W couples preferentially to LH objects.  In top decays this results in W having a preferred spin orientiation. In SM the longitudinal W should be produced 70% of the time.  This affects angular distribution. 2 Tops are produced with their spins either aligned or unaligned.  for other quarks this info is washed out… for top its translated to final products and affects the angular distribution of final state leptons. I said t->Wb… Ture 99% of time but occasionally Ws or Wd.  Described by CKM mixing matrix. Vtb the element that says how often t couple to b is ~100% and the width to is related to the

Let me make a few comments on New Physics.  If any of the measurements I showed disagree, this could be a sign of new physics.  For example if a new X particle was producing top, you’d see too many events.  If a new X particle was in the decay chain, you’d get different end states.  You might see a resonance as some models predict.  Some models even suggest that tt IS the Higgs.  There is another theory which theorist love called SUSY a summitry between fermions and bosons.  Nobody has any evidence for it, but theorists lug it.  In the simplest version of this theory you get 5 Hags, and the charged one prefers to decay to talus.  If it is around top might decay to it giving more talus in the final state.  Precisely because the number of lepton decays was more or less as expected, limits can be set on a SUSY Higgs in the mass-tanbeta plane.  beta a parameter of SUSY.

Let me turn now to what top can tell us about Higgs.  I’m somewhat reluctant to show this because we have one of the world experts on this subject in the room.  Earlier I showed how loop corrections could tell us indirectly where the top lay.  In a similar way loop corrections on top can tell us where the Higgs is.  The W and mass can be calculated from other basic quantities, mz, gf (strength of the weak interaction) and alpha (strength of the em).  Loop diagrams show dependce on top.  This plot, which Martin showed at the big physics meeting this year, has the top q on this axis and w on this.  The RED curve shows the 68%cl for where W and top should be from LEP.  The GREEN curve is the direct measurement of both from Lep2 and Tevatron.  The AGREEMENT shows the excellence of the Smodel once again.  But also, in orange is the effect of the Higgs.  Note this deltaR is also a weak function of the Higgs mass and from this we can say that the Higgs is more likely light than heavy.