Star-tpc-l mailing list

[Richard Witt <witt AT usna.edu>]

Present: Alexei, Mathias, Jim, Emmy, Gene, Yuri, Flemming, Grazyna, Sonoraj, Aihong, Daniel, and myself

== Hardware

— started gas system recovery

— TPC currently in nitrogen flow (after purge), about 80 l/min

— most sensors are off

— started with dryer, then cooling down

— lasers: west looks okay, east has several mirrors damaged (and intensity is not very high)

— may want to change mirrors inside box

— will discuss further with Yuri how to measure TPC movement

— during sensor install noticed that TPC was already at limit

— will make another measurement with more accuracy

== Electronics

— Tonko and Tim are doing inventory and status checks

    

== Software

— Run 22 p+p 500 SC

— nothing new for this week on SC

— Mathias looking at test production with new alignment

— see plots posted to list and/or on Drupal agenda

— checked with and without 2 cm shift in proximity cut for z-axis to account for FXT target location

— have also noticed excess of forward rapidity tracks with decreasing energy (opposite expected)

— amounts to ~10% more tracks in forward rapidity in test production

— may want to request a test embedding sample with the new alignment

— Gene mentioned that with the 2 cm shift, we may need to tighten the 3 cm primary cut to avoid tracks from beampipe

— there are also z-cuts and ToF matching cuts used

— Emmy looking at matter antimatter mass differences for tritons, He3, and He4

— see talk posted on Drupal

— general agreement between protons and kaons

— some azimuthal variation visible even in proton and kaon mass comparisons

— difficult to see in pions due to difficulty of measurement itself

— similar variation in eta

— perhaps a static field issue?

— Gene mentioned a possible cross-check to identify TPC sector alignment

— also, there is a suggestion to exclude tracks that cross the central membrane

— Gene mentioned that using new chain option cause jobs to take longer in tracking

— potentially doubles in time 

— needs to be understood

— Run 22 pp500 SC was waiting for new alignment, but may need to move forward with production is this increase in tracking time cannot be resolved in reasonable time

— if we proceed with calibration production without new alignment, SC would be considered already done, dE/dx would be next

— Yuri has finished dE/dx  calibration with new TPC alignment, using BES-II fixed target data available on HLT farm.

— see: https://drupal.star.bnl.gov/STAR/system/files/RunXIX_XXI_fixedTarget_dEdx.pdf

— Yuri has also started 4p59GeV_fixedTarget with TFG24e which includes new dE/dx calibration and adjustment vertex seed cuts

— see /gpfs01/star/data25/TpcAlignment/TFG24e/2019/RF/4p59GeV_fixedTarget/

— So far it has been processed ~31.983M events. 

— The kfp Analysis is coming.

== AOB

— Nothing new from this week.

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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