sPHENIX MAPS tracker discussion

[Xiaolong Chen <xlchen AT lbl.gov>]

Hi Jin,

Slide 6, in B+ reconstruction, the cuts is optimized with no PID case. As you can see, background is less than signal, So the significance is dominated by signal counts. For clean PID, signal eff is lower, so the significance is worse. For non-prompt D0, it has very high background level, TOF PID can decrease much background. But the cuts is not optimized now. Significance for non-prompt D0 can be improved. 

Another difference I forgot to mention in my slide: for B+, Clean PID is only applied for kaon,  two pi use noPID. A better method is pi using hybrid PID. Anyway, with current tuned cuts, the difference will be very small, due to very low background level. For non-prompt D0, clean PID is applied for both pion and kaon.

Slide 8, this is just a Inv. Mass distribution similar to unlike sign in real data. For significance calculation, B and D0 mass window is with ~3sigma.

Xiaolong Chen

在 2017年6月2日，13:23，Huang, Jin <jhuang AT bnl.gov> 写道：

Dear Xiaolong

 

That is very interesting development. And thanks for working out the first exclusive B-meson projection for sPHENIX!

 

Few questions and comments:

 

·       Slide 6: TOF availability. Is the difference between Hybrid PID and Clean PID comes from the TOF efficiency? And track missing TOF is dropped in the Clean sample? It is interesting to find the Clean PID sample has worse performance than hybrid, but that is probably because I am not sure about their definition.

·       Slide 7/13: It is great to know the precision is good in the mid-pT region, even in central collisions with or without PID.

·       Slide 8:

o   May I confirm mass cuts on both B+ and D0 vertexes are used for these studies? Alternatively, would the two masses be useful to be used as an additional TMVA variables?

o   May I confirm a guess that PID detector helped less in the exclusive B+ analysis (when compared with the non-prompt-D0 analysis) is that, the B+ invariant mass cut automatically selected higher momentum track candidates?

·       For final plots, please use the newly appointed sPHENIX style set: https://github.com/sPHENIX-Collaboration/macros/tree/master/macros/sPHENIXStyle

 

Again, thanks for the nice study!

 

Cheers

 

Jin

 

______________________________

 

Jin HUANG

 

Associate Physicist

Brookhaven National Laboratory

Physics Department, Bldg 510 C

Upton, NY 11973-5000

 

Office: 631-344-5898

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From: sPHENIX-HF-jets-l [mailto:sphenix-hf-jets-l-bounces AT lists.bnl.gov] On Behalf Of Xiaolong Chen
Sent: Friday, June 2, 2017 10:00 AM
To: sphenix-hf-jets-l AT lists.bnl.gov; sphenix-maps <sphenix-maps-l AT lists.bnl.gov>
Subject: [Sphenix-hf-jets-l] Bplus reconstruction update

 

Hi All,

Please find the direct B+ reconstruction in the link:

http://portal.nersc.gov/project/star/xlchen/sPhenix/Bpm/Ana/slides/Bpm_sPHENIX_170602.pdf

Any comments?

Thanks and best regards,

Xiaolong Chen