Minutes of Meeting 14/8/08

Present: Roberval, Clare, Mark, Joel

• Roberval showed plots of his studies on the 230 GeV sample of Z->µµ+H, some of which have been discussed before. There was discussion of a dijet mass cut vs the recoil mass cut, but the dijet mass from the Higgs shows a long tail at lower values. Using a dijet mass plus Z energy cut does give very good background rejection for a signal efficiency of about 1/3.



• Mark's plots from Monday for the 250 GeV Z->ee samples are similar, but have been showing a high tail in the dijet mass spectrum (particularly in the ZZ).



• After some further investigation and discussion in the meeting, it was decided that:
  • The long low-mass tail in the Higgs dijet mass plots is probably neutrinos. Mark and Roberval should check this by adding
    in neutrinos from the MC
  
  
  
  • The high-mass tail in the electron samples is mainly due to photons (primarily FSR and Brehmsstrahlung) being included in the jets. Mark is looking at using a smaller Ycut to isolate photons (and taus) and then veto any jet with less than two tracks, as shown in his latest plots. He has also looked at picking out photons close to primary electrons.
    



• There was some confusion about whether we are expected to give a status report in the ILD meeting next week [it's actually the week after]. Since Victoria gave the last talk, it was decided that someone from Bristol (Mark) should give the next one.