Star-tpc-l mailing list

[Richard Witt <witt AT usna.edu>]

Present: Alexei, Mathias, Jim, Emmy, Zhangbu, Frank, Gene, Yuri, Tommy, Grazyna, and myself

== Hardware

— most things going well

— several RDOs bad

— access tonight (primarily for sPHENIX), beam after midnight

— tried 111x111 last night, failed so returned to 56x56

— drift velocity has recovered (trending up toward 5.5 cm/us) since adding slightly more methane

== Electronics

— Tonko may be able to repair some boards today depending on schedule

— anything done will be reflected in the log book

    

== Software

— Run 22 p+p 500 SC

— waiting on new TPC alignment

— Emmy looking at mass difference between light nuclei and light anti-nuclei

— asymmetric effect of SC on charge signs is important to her analysis

— looked at difference in mass^2 for protons from isobar dataset 

— clear difference in mass^2 observed over pt which even diverges with increasing pt

— apply a correction based on assumption of inaccurate momentum measurement

— momentum inaccuracy taken to be proportional to momentum

— new correction works well out to about 2.5 GeV/c

— may need to look at dependence on Z position of the tracks

— another suggestion is to look at dependence on azimuthal position

— need someone to also look at other datasets to see if same effect is there 

— perhaps also look at luminosity dependencies 

— 

— TFG24d

— going forward with dE/dx calibration production from HLT farm in meantime 

— next is to go forward with new alignment and check other data samples

— Gene noted that calibration production usually comes after distortion corrections have been applied

— calibration production for fixed target could happen immediately

— other (non-FXT) sets will need distortion correction pass first

== AOB

— some discussion of increase in hit errors fro 2016 Au+Au 

— question of relative benefit attributable to increased errors vs inclusion of more noise

— increase in hit errors serves to include hit in pattern recognition during track finding

— but because errors are large, the tracks are not unduly distorted

Best Regards,

  Richard

Sent from my iPad

-- 
"Education is the most powerful weapon which you can use to change
the world."

--Nelson Mandela

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 Richard Witt, Professor of Physics     Phone (USNA): 410-293-6675
    United States Naval Academy         Email: witt AT usna.edu
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