PRD Draft v1 (a0_prd_v1)

My notes

• QCD production: not properly mentioned is here the category of fake muons: "mimicked by prompt or hadrons arising from heavy flavor decays"
  I find that the following need to be explicitely mentioned:
  • pion or kaon decay in flight (DIF) they result in a real muons
  • hadrons punching through the calorimeters, these are not real muons but they can cause a number of hist in the chambers, they can be several particles
  • mention that those hadrons can be either from prompt production or from heavy flavor production which has some relevance for the impact parameter distribution

• for Upsilons which are prompt the tight SVX efficiency is measured to be 25.7% (purely geometrical): eps = nAcceptedSvxTight / nAccpetedCotOnly

• the efficiency of tight SVX requirements on two trigger muons from heavy flavors is 23.7% using J/psis eps = (nAcceptedSvxTight / nAccpetedCotOnly) which are re-weighted to represent the muons from decay of heavy flavor
  • I do not understand how this works? what is re-weighted? based on the single muons pT? and was the distribution of simlulated muon pT compared to the data? it at least needs to be shown that the B pt spectrum is fine, I would belive the EvtGen decay for sure, probably this is all fine but I do not understand it how it is written
  • why is the 7% comparison made? are the muons from Upsilon and heavy flavor not anyway also different and would need to be adjusted at least for pT? and J/psi are predominantly prompt, so how can it reflect the heavy flavor decay length?

• do simulated events ever show an impact parameter distribution with a long tail? this question is answered in Pasha's presentation from July 16 and in the CDF note 9375 and the bottom line is that the tails do exist even in the simulation more then 50% stem from nuclear interactions

• now with loose SVX requirement the efficiency is measured to be 19.3% which is expected to be 24.4% taking just geometrical arguments...
  • I do not understand how I get the 24.4% (well 23.7% + more because we accept larger impact parameters)
  • but it is a mystery how I get 19.3%? again using Jpsi/Upsilon?
  • the unexpected background is huge!! 153895±4829 events with no SVX requirements? after applying loose SVX requirements it is cut in half (72553±7264) while known processes get diminished by factor of 88%
  • ghosts are half SS and half OS

• D0 study shows that ghosts are non heavy flavor, so what? well if they are mistakenly counted as heavy flavors the count is screwed up, but what it really tells is unclear. punch through would look like this because dijets would generally not be containing heavy flavor

• plot 4: I am not sure I really understand the argument why the picture excludes the hypothesis of unexpectedly large Lorentz boost, nor do I understand why we need to worry about unexpectedly large Lorentz boost. On the other hand the picture tells me, that for "real muons" or at least "prompt real muons" the efficiency is higher (at the Z mass the efficiency is enhanced), for non-prompt muons, or fake muons the efficiency is lower, which seems sensible. Remember:
  (a) a non-prompt muon is displaced and might miss a layer as long as the boost is large enough,
  (b) a fake muon has a higher chance to originate from a secondary interaction then a real prompt muon and thus has lower efficiency in the SVX.

• fit of average B lifetime in the range 0.12 - 0.4 cm comes out to exactly agree, hmmm this needs to be tested whether the argument is really valid, I doubt it. first vary fit interval, second what is the prediction after some reasonable corrections.... composition and trigger cuts applied.... very dangerous the study

• stopped at page 14 : decay in flight (DIF)

Glossary

• DIF:
  Decay In Flight

• tight SVX selection:
  request hits in 2 innermost layers and 2 more in remaining outermost layers. usually refers to selection of the trigger muon tracks only! (innermost layers means including L00?)

• loose SVX selection:
  request at least three hits in SVX and ISL layers. usually refers to selection of the trigger muon tracks only!

• QCD production:
  Each muon track complies with tight SVX selection. The known sources of reconstructed muons are semileptonic decays of bottom and charmed hadrons, prompt decays of quarkonia, Drell-Yan production, and muons mimicked by prompt hadrons or hadrons arising from heavy flavor decays. The SVXII quality requirements reduce the data sample to 143743 events.