Search for extra-boson from Top Decays Jenna Lane, Paul Miyagawa and Un-Ki Yang Manchester Christmas Meeting, Dec
2 Motivation Search for extra boson from top decays (top->Xb, where X->jj) using a dijet mass Charged Higgs is a good candidate at low tan( ) Provide a Jet Energy Scale information using a standard W mass W+W+ W - (H-) t t b-jet jet M jj
3 Method Use a kinematic top mass fitter developed at CDF Default fitter: M_W(jj)=M_W(l )=80.4, M(top)=M(anti-top) Modified fitter: W(l )=80.4, M(top)=M(anti-top)=175 GeV Lepton+jet channel with double b-tagged events W (80) H+(120) top->H + b, H + ->csbar using CDF MC
4 Improvements in dijet mass? Poor resolution for Njet>4 Better handling on the 5th jet Detailed studies of extra jets Δ R (5th-jet, L4jet)<1, merge it Good improvement For 2 Hjets
5 Status and Plan A dijet mass resolution has been improved. A binned likelihood fitter works. Plan to make ATLAS MC samples and finish sensitivity studies Jenna Lane (student) and Paul Miyagawa (postdoc) will join this effort. toy exp.:H:W:B=1:1:1
6 Other Activities Systematic studies on the extra- jets (ISR/FSR) Dominant systematic for precision measurements at LHC Extend CDF ISR/FSR studies to LHC region with other ATLAS colleagues High Level Trigger: plan to spend 50% efforts on this projec. By M. Cobal
7 Backup Current Limit on the charged Higgs BR(t H ± Assuming BR(H ±