Minutes for HF PWG meeting on 2015/03/19

1) Upsilon 2S/3S in U+U Run 12 - Robert
Suggestion from the group: add results for Upsilon(23),Upsilon(3S) (Raa vs Npart, vs Ebinding) to the paper
2) Upslion Npart weighting - Robert
Not weigh the Nbin (it biases the results)
Npart could be weighted by Nbin to better present the <Npart> point where Upsilon is produced (Daniel's suggestion, such approach was used by ALICE in http://arxiv.org/pdf/1202.1383.pdf) but it is also fine to leave it as it is and write clearly in the text how the position was obtain (average weighted by number of min-bias events)

3) Exercise with Kpi mass - Leon
Liang: nice signal, but strange osculations in the mass distibution
suggestions
- check positive/negative ratio
- check if this could come from particle misidentification
- check pion-pion mass spectrum to see if this is a detector effect

4) D0 in Au+Au run 14 - Mustafa
- first, promising D0 results
- new PicoD0 structure
- a few questions about what is the efficiency of the currents cuts (dca, decay lengh, pT etc) - this has to be tuned to make sure we do not remove too much signal (example for momentum correlation plot from Spiros: for example:  http://www.star.bnl.gov/~jai2006/temp/pKpi_AllpT.png)
- new approach to the secondary vertex finder implemented
- comment on the StHelic code used to find a DCA between tracks - current algoritms paramters do not provide good accuracy. Mustafa will follow on the upgrade of StHelix (additional Set/Get methods to control initial values of DCA and step in the algorithm or a specialized version of StHelix for HFT)

Xin - a few changes in the PicoDst structure to save space,
Full DcaGeometry saved in pico  allowing KFParticle fit in analysis
Question about improving the vertex finder (using KF vertex):
- if running the KF vertex finder as a afterburner is tested, then we can add necessary variables to the picoDst structure to allow users to use it for their analysis
- nevertheless, the correct vertex could be found by requiring correlation with VPD position

Xin will prepare a prepare disc space request for PicoDsts for HF PWG.

David: D0 paper proposal:
- more details on pion pT spectrum need (and syst. errors) since this will be first publication of this data
- make sure that plots are readable in a gray scale
- too many FONLL predictions, remove one (Ramona D* for instance)
- a long discussion regarding if a difference in the fragmentation fraction function for D0 and D* could change the cc-bar cross section results
suggestion: make a plot with the data (measurements) first, then add a plot with charmed mesons with fragmentation uncertainties included (and all other uncertainties relevant for charm cross section calculation), maybe include correction for pT shift for D*  pT to D0 pT based on model calculations.

Bingchu: J/psi in p+P 200 GeV
New study with improved statistics,
slide 6 - for HT data there is also match to triggered tower
to check - dN/dphi for hadrons and J/psi and correct for acceptance using event mixing
an issue: a different hadron yiedl per trigger compared to published run 9 results (factor of 2)
todo: check if ToF matching efficiency explains the different in the yield per trigger

General comment: we (Physics Working Group) should create work plan to make sure all interesting physic is covered:  topic of interest, how much resources need, also if embedding will be required