Dear Colleagues, Due to family constraints, it turns out that I will not be able to attend the Tevatron Connection, much to my disappointment. I thought it would be useful to at least send my thoughts, and to invite anyone to contact me if they want to discuss any of these topics. You will find a bibliography of relevant papers at the end of this message. Scott 1. Wh or Zh, with h->bb: More effort has gone into these processes than any other Higgs process at the Tevatron, so it is hard to find anything new to add to the discussion. Let me just remind you that these processes are thought to be extremely challenging at the LHC, and so if they are going to be seen, the Tevatron is the place to see them. There is a very recent paper by Sullivan that criticizes the accuracy of Pythia/HERWIG for modeling single-top production. Recall that single top is a serious background to these Higgs processes. Sullivan will be speaking on single top on Monday afternoon in the Precision Electroweak session. 2. bb-> h and gb->hb : In a generic two-Higgs-doublet model, some of the physical Higgs bosons have enhanced couplings to bottom quarks for large tan beta. Large tan beta is actually attractive, because it supplies an alternative explanation of why the top quark is so much heavier than the bottom quark. In the standard model, this is because the top Yukawa coupling is much larger than that of the bottom quark. But in a two-Higgs-doublet model with large tan beta, the top and bottom have similar Yukawa couplings, but the bottom quark couples to the Higgs field with a small vacuum-expectation value, while the top quark couples to the other Higgs field. This suggests that we should expect tan beta around mt/mb = 40, although smaller and larger values are also possible. A well-known two-Higgs-doublet model is the Higgs sector of the MSSM. At large tan beta, one of the Higgs scalars acts like a SM Higgs, while the other Higgs scalar and the Higgs pseudoscalar have enhanced coupling to bottom quarks. If these are light enough, they may be accessible at the Tevatron. See the paper by Boos et al for further discussion. If a Higgs boson has enhanced coupling to bottom quarks, it may be produced via this coupling. Let me discuss two possible channels: a. bb->h, i.e., inclusive production of the Higgs. This calculation makes use of the b-quark distribution function in the proton sea, which is calculated perturbatively from the gluon distribution function. Alternatively, one can ignore the b distribution function, and calculate the inclusive cross section from gg->bbh. The two calculations should give the same result. At the time of the Run II SUSY/Higgs workshop (Carena et al.), these two calculations differed by an order of magnitude, and it was not clear which was closer to the truth (bb->h was the larger of the two). It turns out that the cross section based on bb->h was the more accurate. The inclusive cross section based on gg->bbh has now been calculated to NLO (see Dittmaier et al.), and it agrees with the NLO bb->h calculation within uncertainties (see Les Houches proceedings). However, the bb->h cross section has now been calculated to NNLO, which makes it the more accurate of the two calculations (see Harlander and Kilgore). This demonstrates one of the advantages of using the b distribution function for calculations. The NNLO bb->h cross section has very little theoretical uncertainty. I noticed that the inclusive cross sections for this process given in the talk of Hanagaki are low by about a factor of two, and have bigger uncertainty than the NNLO calculation. I advocate using the cross sections in the Harlander/Kilgore paper (which are also given in Les Houches), since they are the most accurate available. b. gb-> hb : The idea here is to use the b jet in the final state to reduce backgrounds. This cross section has been calculated to NLO (see Campbell et al.). A very recent paper by Dawson et al. compares this with gg->bbh at NLO (where at least one b is at high pt). The two agree very well, as they should, and have similar uncertainty. However, the recent paper by Dawson et al. includes a diagram, involving a top-quark loop, that is negligible at large tan beta. Hence their numerical results cannot simply be multiplied by tan^2 beta. For this reason it is preferable to use the numerical results of Campbell et al. (see the code MCFM). Topic for discussion: What is the best way to model these processes with a shower Monte Carlo? a. bb->h : At LO the h is produced with zero pt. It acquires pt from initial-state radiation. While this is probably accurate at low pt, it will not do a very good job at high pt. However, there are not many events at high pt. At high pt, the most important process is gb->hb, with bb->hg of secondary importance. Alternatively, one could use gg->bbh as the LO process in the shower Monte Carlo. I'm not sure it will do as good a job at low Higgs pt. Will it capture gg->bbhg, where the g is radiated from a virtual b line (the analogue of bb->hg above)? b. gb->hb : Here we are interested in tagging a final-state b jet. There may be additional jets in the final state. It is a surprising but true fact that the largest such contribution is from gb->hbg, with gg->bbh of secondary importance. If one used gg->bbh as the LO process, then the analogue of gb->hbg would be gg->bbhg, with at least one b at high pt. Starting with gb->hb as the LO process, a second b jet would sometimes be generated by the shower MC from the backward evolution of the initial-state b quark (g->bb). Sullivan has argued that b jets generated from gluon splitting in the initial state by the shower MC's is a poor approximation. This would argue in favor of using gg->bbh as the LO process. Bibliography: 1) UNDERSTANDING SINGLE-TOP-QUARK PRODUCTION AND JETS AT HADRON COLLIDERS. By Zack Sullivan. FERMILAB-PUB-04-142-T, Aug 2004. ** Temporary entry ** e-Print Archive: hep-ph/0408049 2) THE MSSM HIGGS BOSONS IN THE INTENSE COUPLING REGIME. By Edward Boos (Moscow State U. & DESY), Abdelhak Djouadi, Margarete Muhlleitner (Montpellier U.), Alexander Vologdin (Moscow State U.),. PM-02-10, May 2002. 50pp. Published in Phys.Rev.D66:055004,2002 e-Print Archive: hep-ph/0205160 2) REPORT OF THE TEVATRON HIGGS WORKING GROUP. By Higgs Working Group Collaboration (Marcela Carena et al.). FERMILAB-CONF-00-279-T, SCIPP-00-37, FERMILAB-PUB-00-349, Oct 2000. 185pp. Part 6 of Physics at Run II SUSY/Higgs report: available as fermilab-pub-00-346-1 (part 1), hep-ph/0003154 (part 2), hep-ph/0008070 (part 3), and hep-ph/9906224 (part 4), and hep-ph/0006162 (part 5), and hep-ph/0010338 (part 6). e-Print Archive: hep-ph/0010338 3) HIGGS RADIATION OFF BOTTOM QUARKS AT THE TEVATRON AND THE LHC. By Stefan Dittmaier (Munich, Max Planck Inst.), Michael Kramer (Edinburgh U.), Michael Spira (PSI, Villigen),. EDINBURGH-2003-13, MPP-2003-49, PSI-PR-03-14, Sep 2003. 12pp. e-Print Archive: hep-ph/0309204 2) HIGGS BOSON PRODUCTION IN ASSOCIATION WITH BOTTOM QUARKS. By J. Campbell, S. Dawson, S. Dittmaier, C. Jackson, M. Kramer, F. Maltoni, L. Reina, M. Spira, D. Wackeroth, S. Willenbrock (Argonne & Brookhaven & Munich, Max Planck Inst. & Florida State U. & Edinburgh U. & Enrico Fermi Ctr., Rome & PSI, Villigen & SUNY, Buffalo & Illinois U., Urbana),. May 2004. 7pp. Contributed to 3rd Les Houches Workshop: Physics at TeV Colliders, Les Houches, France, 26 May - 6 Jun 2003. e-Print Archive: hep-ph/0405302 2) HIGGS BOSON PRODUCTION IN BOTTOM QUARK FUSION AT NEXT-TO-NEXT-TO LEADING ORDER. By Robert V. Harlander (CERN), William B. Kilgore (Brookhaven),. BNL-HET-03-4, CERN-TH-2003-067, Apr 2003. 16pp. Published in Phys.Rev.D68:013001,2003 e-Print Archive: hep-ph/0304035 4) HIGGS-BOSON PRODUCTION IN ASSOCIATION WITH A SINGLE BOTTOM QUARK. By J. Campbell (Argonne), R.K. Ellis (Fermilab), F. Maltoni, S. Willenbrock (Illinois U., Urbana),. ANL-HEP-PR-02-027, FERMILAB-PUB-02-062-T, ILL-TH-02-3, Apr 2002. 25pp. Published in Phys.Rev.D67:095002,2003 e-Print Archive: hep-ph/0204093 1) HIGGS BOSON PRODUCTION WITH ONE BOTTOM QUARK JET AT HADRON COLLIDERS. By S. Dawson, C.B. Jackson, L. Reina, D. Wackeroth. BNL-HET-04-12, Aug 2004. 4pp. ** Temporary entry ** e-Print Archive: hep-ph/0408077