Guannan:
Study on of an issue of different relative HFT efficiency vs time.
If not solution found, this part of the data (with low eff.) will not be used for the data analysis before the QM'15
HFT ratio - strong dependence on Vz and phi, some dependence on luminosity
- HFT relative eff. will be calculated vs pT, eta, vz, centrality. Phi dependence is under consideration, whether it is necessary or not to include it (eff. as a function of phi). The phi-averaged value should be fine if there is no significant effect due correlations of the D0 decay daughters
- efficiency vs phi may depend on many different factors (pT, eta, Vz). Xin commented, that similar check was done for di-electron (averaged correction vs correction in different dimensions) and the effect was small. So the current approach is to use the efficiency averages over phi and then check the syst. effect.

- event mixing - same event like-sign, mixed-event like-sign and unlike-sign distributions are consistent, nice D0 peak -> event mixing seems to work
- peak around 0.8 GeV/c2 - possible explanation K0s -> pi+pi- reconstructed when one pion is taken with kaon mass.  More on that in Mustafa's talk.

Data production wit KF vertex - 70% ready, KF and original vertices stored in a separate tree, which should be loaded into the analysis maker.

Micheal:
event mixing:
Read-me and a reference for users.
event mixing seems to work
"bump" around mass of 1.6 GeV is not reproduced - probably physical signal, maybe a resonance reconstructed with wrong daughter mass assumption (kaon mass instead of pion's ?)

Md. Nasim
- what are the topological cuts? Please add distributions
- slide 4: to check: why black points missing in some bins?

Daniel:
Purity study vs momentum:
- take into account stat. error on pt vs p distribution
- check z-test values (if consistent with chi2)

Mustafa:
- foreground simulations can describe mostly the bum ~ 1.6 GeV
- some contribution is still missing - maybe contribution from jets/some other source (as shown by Liang's study with Hijing)
- question - can this be from uncorrelated charmed meson decays? Could be, but the yield is expected to be small. We should check it with Hijing events.
- Liang commented, that he sees some discrepancy compared to the Mustafa's results using the same approach (smearing of the DCA to mimic correct topology cut efficiency)
- question - what is the charm cross-section in Hijing?
- question - are all the decay channels correctly included? Same for the BRs.
- peak ~ 0.8 here and in the Guannan's results are different, need to double check
- could it be due to K*or Lmbda? Rather not Lambda (was checked, mis-PID gives wrong mass)
- is the wrong position due to momentum bias (energy loss) - was checked with K0s->pipi, the peak position was correct.
- next steps - work on improving the estimates of the momentum resolution, including other efficiencies and look for potential sources of the peak ~ 0.8 GeV and the bump ~ 1.6 GeV.