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Kaon LT Meetings » mtg_23apr13.txt

Garth Huber, 04/13/2023 06:43 PM

 
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                Apr 13/23 PionLT/KaonLT Analysis Meeting Notes
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                 ---------------------------------------------
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                              (Notes by GH)
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                    Today: KaonLT will be discussed first
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Please remember to post your slides at:
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https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings
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Present
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-------
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Regina - Ali, Alicia, Love, Junaid, Vijay, Garth
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CUA - Tanja, Richard
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FIU - Pete
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At GHP: Stephen, Nathan, Dave G
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Regrets: Julie, Jacob
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Richard Updates
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---------------
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PID investigation
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- now doing a proton subtraction, but normalizing to the beam charge
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- getting a large over-subtraction of the data
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   - GH: need to normalize to the size of the omega+p peak, not the charge
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   - the idea is to use the data to understand the MM-shape of the proton
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     leakthrough
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   - the efficiency of the proton cut can be low, need a clean proton sample to
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     be sure you aren't subtracting Kaons
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   - the differing cut efficiency for K+ (with leakthrough) and protons (with
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     minimal contamination) can be large, so normalizing only to beam charge
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     won't work
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- deal with pion leakthrough subtraction the same way, normalizing to the pi+n
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  peak
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- Ali and Richard meeting tomorrow at 16:00 Eastern to discuss PID
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Lumi Issues
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- no report today, will wrap up loose ends soon
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Ali Updates
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-----------
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Pion PID study for all Q2>2.0 data, five settings in total
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- uses HGC to remove K+ leakthrough (keep NPE>1.5 events)
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   - other cuts: acceptance, e-pi cointime, aerogel
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- analyzed so far: low epsilon (spring 2019), high epsilon (fall 2018) still
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  running
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- MM spectra look clean, even up to Q2=5.5, looks like no K+ leakthrough
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  subtraction will be needed, which is good news
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- GH: it will be important to study PID cut efficiencies as well, so that we
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  are sure we aren't using a cut that leads to a large systematic uncertainty
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   - AU: HMS Cer+Cal have stable effs
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         SHMS aerogel efficiency also good
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         Tracking has rate-dep efficiency we will calculate run-by-run
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   - The real issue is the HGC efficiency, no hole cut applied yet
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      - need to implement the HGC hole cut, meeting tomorrow will discuss this
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      - two possibilities:
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        a) divide HGC into 2 sections, remove hole with eff<75-80%, correct the
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           rest for inefficiency
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        b) divide HGC into 3 sections, remove eff<50%, correct 50-80%, 80-100%
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           regions separately
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      - it would be easier to implement 2 sections, at least for pi+ analysis
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        but we need to do study to check
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      - also need to apply same hole cut to SIMC
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      - RT: we have the algorithm from Peter B, need to implement it
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   - once the HGC hole cut is implemented, it will be interesting to see if
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     Alicia notices any BSA difference with it, particularly the 2nd t-bin,
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     which always looks anomalous
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- CoinTime also used to select PID
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   - GH: maybe we need to apply a CT cut efficiency
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   - use the HGC and aerogel to get a clean event sample, then plot CT for
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     these events to get a better idea of a good cut for pi+, K+ analyses
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   - so far, the CT plots that were made were without HGC cut, so the
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     contamination from other channels is larger
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   - the cleaner sample will enable the CT cuts to be optimized, particularly
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     for K+ analysis, which has contamination from both pi+ and proton sides
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- TH: in Fpi-2 she did a study, and determined that a correction wasn't
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     required.  Need to do a similar study here.
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   - CT resolution is worse than in Fpi-2
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- For K+ almost certainly we need to apply a correction
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- For Vijay's low Q2 pi+ analysis, the study needs to also be done, but should
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  be quick and the correction small (if at all)
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- Ali will have to do separate studies for low and high epsilon data, due to
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  differing conditions
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- GH: Also we should do a quick check if RF cut needed or not
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   - AU should check if pi+ MM spectrum changes shape (particularly in Delta
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     region) with and without RF cut
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   - if shape does not change, irrespective of yield change, then RF cut
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     probably not needed
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   - K+ may be a different situation than pi+
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Vijay Updates
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-------------
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Data/SIMC plots for each t-bin
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   - 8 t-bins, 16 phi-bins
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   - mid epsilon at Q2=0.38 shown
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- Plots of Data/MC ratio versus phi-bin for each t-bin
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   - see clear oscillations (interference terms wrong in model), but overall
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     surprisingly close to R=1
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- GH: don't worry about the ratios for now, we need to be check instead if the
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  code is working properly
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   - for example, do the error bars propagate correctly from one SHMS setting
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     to combined 5 SHMS settings
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   - at higher -t, we see phi-bins which have much worse statistics than
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     others.  This is presumably due to incomplete phi-coverage at higher -t,
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     but we should be sure
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   - plot R vs phi-bin for each SHMS setting separately, and compare to the
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     combined phi distribution to see if it all makes sense
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Shows a few sample SHMS xptar, yptar plots
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   - Green=Data, Blue=SIMC
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   - general agreement looks good
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   - still working on other plots
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- GH: you will find it more convenient to make a PDF of several plots on a
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  page, sorted by theme
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   - this will let you more quickly investigate if things are looking okay as
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     you do the iterations
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Next 2 week plan is to finish the plots and initial yield study
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EIC Meson WG Discussion
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-----------------------
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- TH: next meeting is Thur April 20 @ 9:00 Eastern
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   - we should discuss next plans, including a future paper
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- GH: has some questions on how new ePIC WG structure will work
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   - seems to be more detector focused, less on the physics than before
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   - in that scenario, the Meson WG will become even more important
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- should include JLab 22 GeV as well as 2nd detector issues, not just ePIC
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Next Meeting
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- Thur Apr 20 @ 16:00 Eastern/14:00 Regina/13:00 Pacific
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- PionLT will go first
(207-207/443)