Group Meeting:

Dmitry Khaneft *pbarp->e+e- study with PANDAroot

• Show slides of first simulation/analysis of pbarp->e+e- with PandaRoot. Anti-p_Momentum=10GeV/c; G_e/G_m=0

• Cuts: 1 positive and 1 negative track are required.

• Cuts: E/p>0.7 (condition for electrons; E is the energy deposited in the calorimeter)

• To do: e+ multiplicity vs. e- multiplicity.

• To do: Check dE/dx for STT, check the total number of entries, it has to be the same as for the multiplicity integral plot.

• Invariant mass plot: Does it make sense the peak around 4GeV? Is that with or without the cuts? What are the entries at very low W?

• Background: missidentification? "Electronic" noise?

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Frank Maas about e-mail from Stefano Spataro

• A relation about how pid works in panda root is described in this e-mail:

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Am 15.12.2010 um 11:17 Stefano Spataro:

Hi,

at present there are several detectors providing a bayesian pdf in a separate way. They are: MVD, STT, DISC, DIRC, using of course de/dx and Cherenkov angles. MVD needs an update, but this effects only very low momentum particles. No TPC pid is available because nobody from TPC group has ever implemented the energy loss calculation.

For EMC, Ronald is preparing pdfs using bayes, only with the e/p information. After setting it, he will try (hopefully) to add shower shape variables. About EMC MVA, this includes e/p and also a list of shower properties http://panda-wiki.gsi.de/pub/Computing/PandaRootPapers/Panda_doc.pdf For MDT, there is a had cut algorithms, using the amount of iron crossed by the particle as a function of the particle momentum at the entrance point in MDT.

They are well separated, but bayes is modular, and it is possible to merge different probabilities to have a global value. Of course this is analysis dependent, and one should also calculate particle flux for the desired channel, but I suppose fluxes were calculated in the other framework than one could use exactly what already done (at least, particle physics should not depend on the software, hopefully). In MVA one can also add STT+Cherenkov informations, but this has to be discussed in details with Mohammad Babai who is the expert.

Hopefully Ihgave you all the relevant details about the current PID situation, do not hesitate to ask me further questions.

Best wishes to everybody.

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Mamen Mora * Simulation ppbar->e+e-pi0 a la Lansbergf

• Showed plots in relation with the simulation/analysis of pbarp->e+e-pi0 a là Lansberg.

• To do: How many combinations of charged +/- and pi0 do I get per event?

• To do: How is a gamma defined to fill the lists?

• To do: Are the pidelectron lists exclusives or inclusives?

• To do: How is the gamma direction defined?

• The Pi0 mass reconstruction: Talk to Bertram and ask if it should be better. The values are not consistent with the pi0 mass... They change with W^2. Something writen in the PB about pi0 reconstruction?

• To do: Try the kinematical fit using e+ pi- pi0 and pi+ e- pi0.

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