We search for charge 1/3 LQ produced in pairs and decaying to b-b-nu_tau-nu_tau. Three channels are used corresponding to a low pt muon plus jet trigger, a dimuon trigger, and a high pt (15 GeV) muon plus jet trigger. 2 events remain, and our limits are about the same as CDF's search for charge 2/3 LQ decaying to tau-tau-b-b. In addition to third generation leptoquark results, this work sets limits on ZX production. Note 3175 includes all calculations done to this point. Separate plots of the LQ3 limit and the ZX limit are also available. If we consider a minimal Higgs, then the ZX limits can be compared toZH expectations (the data points are identical and we use PYTHIA to give the cross section and H->bb branching ratio ). We also include two older notes which have some discussions of preliminary studies which are not included in the final writeup: dimuon from Oct. 96 and combined from March 97.
The version posted June 12 includes all mass points (50, 60, 80, 100, 125, 150, 200, 250 and 300 GeV). We significantly increased the statistics since the March in all Monte Carlo channels, and believe we have final results on cross section limits. They are very close to the preliminary March results. During the last few weeks, we increased the statistics on the top background channel, and removed one cut (Xjj) replacing it with a requirement that there be less than 6 jets. The backgrounds and acceptances were recalculated with all limits within 1 pb of the results presented at Stony Brook.
On August 2, the note was updated incorporating larger Monte Carlo statistics for ZX limit calculations. All limits were within 4 pb of the older results. We also include a plot with minimal ZH theoretical expectations.
On September 19, the note was updated to include a discussion on the number of jets in signal and background events.
On November 4, the note was updated including a discussion of optimizing the number of jets and HT cuts. Also, we inlcuded studies of the acceptance variation due to varying pdf and other QCD parameters. The acceptance of vector production was compared to scalar and found to be the same for masses greater than 150 GeV. We also used a phase space suppression factor to set limits for vector LQ when the decay to top-tau is allowed. We added a factor to the systematic error for muonic branching ratio errors, and recalculated all results incorporating better W MC statistics. Results were within 2-3 pb, and mass limits changed by 1 GeV.
On December 22, the note was updated as the vector LQ theory was recalculated with better pdf's and a range of renormaliztion factors. The vlq limits increased to 216 GeV.
It is possibly the final version of the note for LQ3 results. ZX limits were not recalculated and are still the August results.
We have received (on 2/18) and replied to comments from Sharon Hagopian and Hobbs/Paterno/Linnemann.
The last update was on December 22, 1997.