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Apr 23-24/26 PionLT/KaonLT Analysis Meeting Notes
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(Notes by GH)
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Today: KaonLT will be discussed first
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Thursday: Present
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-----------------
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Regina - Garth Huber, Nathan Heinrich, Nermin Sadoun, Nacer Hamdi,
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Alicia Postuma
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CUA - Tanja Horn, Chi Kin Tam, Sameer Jain
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Nacer
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-----
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KaonLT Q2=0.5 LT-sep
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- solved yield problems reported last week (drop in high epsilon event counts)
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- some files used in new replay were incorrect, events were skipped
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- still waiting for final replay jobs to finish
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Chi Kin
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-------
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KaonLT High Q2 LT-sep Q2=3.0 W=3.14
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- ran more iterations after applying t-shifts, still using old optics ME
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- kinematic distributions looking better now. a selection of data vs MC
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comparison plots were shown, comparison now looks good for all 5 SHMS
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settings (both epsilons), while before only 3 looked good
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- working on implementing Gabi's method to optimize kinematic offsets from
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physics data
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- waiting to rerun Sigma0 SIMC events
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- *NB* some questions were raised on what beam energy offset is being used in
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the simulations and replay, CKT should consult with Richard on this
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Alicia
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------
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u-channel analysis
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- working on setting up code for LT-sep iterations
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- started from Junaid's code, need to add the u-channel-specific background
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subtractions
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- documenting things as work progresses
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- looking at Bill's old code to see what checks were done, etc., but applying
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to new analysis framework
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Sameer
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------
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PionLT Q2=1.6 W=3.08 background subtraction
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- MMp plot vs NGCer.npesum shows evidence of electrons caused by pion knock-on
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- *NB* Nathan: suggest to look at MMpi vs PCAL region near 1, that should
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remove the knock-on electron events
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- using NGC cut for Dummy target
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- formed CoinTime random subtraction windows
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- had some questions for group on how to calculate Qeff
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- *NB* should use HMS Calorimeter and Cer efficiencies from Heep data
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analysis, don't recalculate these from physics data, as there will be too
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much pi- leakthrough to get a reliable result
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- other factors to include: TrackEff, LiveTime, pion abs corr, LH2 boiling
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corr from Nathan
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- Nathan: for detectors other than HMS Cal & Cer, the efficiency calculation
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cuts need to be the same as for the physics data
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- The tracking efficiencies depend on the tracking algorithm and the
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particle type, but they should not be particularly sensitive to exact
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details of used PID cuts (on other detectors)
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- *NB* CoinTime Blocking needs to be tabulated in report files and applied
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run-by-run
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Friday: Present
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Regina - Garth Huber, Alicia Postuma, Nathan Heinrich, Nacer Hamdi, Vijay Kumar
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FIU - Pete Markowitz
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JLab - Dave Gaskell
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JMU - Gabriel Niculescu
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CUA - Chi Kin Tam
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Virginia - Richard Trotta
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Glasgow - Rachel Montgomery
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Ohio - Julie Roche
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Richard
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-------
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KaonLT High Q2 LT-sep
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- decided against doing a new Pass-4b replay
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- eneded up re-running the efficiency script on Pass-4a replay data, checked
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some CoinBlock values and they looked good
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- will do a Pass-4c reply with different HMS optics ME
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- Pass-4a has phi-offset=0 and original 2018 ME
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- new replay will have new 2018 ME and phi-offset from
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https://github.com/JeffersonLab/nps_replay/blob/dae2ba5d2db619dc63cd46b9ce5c1f67414b7a96/PARAM/HMS/GEN/hmsflags_opt2018.param
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- plans to start new replay next week
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- *NB* questions raised on whether Richard's empirical fit method to remove
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background underneath Lambda peak is still justified, it may be removing too
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much Lambda radiative tail
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- pion leakthrough w/ Chi Kin's new HGC hole cut is reduced
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- Q2=3.0 W=3.14 hi-eps data MM plot is particularly clean, no evidence of
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background to left of Lambda peak
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- Nathan: raises concerns on whether there is any remaining pion
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background to subtract at all
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- plots shown for other settings have substantial #events to left of
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Lambda peak, but empirical fit seems poorly justified
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- *NB* Gabriel: should compare the MMk spectrum to SIMC Lambda lineshape
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before applying empirical fit, to be sure not too much radiative tail
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is removed
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- *NB* Garth: reminds everyone that SHMS collimator rescattering routine
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in SIMC only is active for pions right now, the code should be modified
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for p,K, as without it SIMC is likely under-estimating the size and
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shape of the Lambda tail
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- Alicia plans to work on this for proton u-channel analysis, can
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include also for K+, will discuss this with Garth offline
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- *NB* Nacer: an empirical fit to the full MM region may be unnecessarily
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complicated, suggests to just fit the region around Lambda before looking
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at Sigma0 region
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Vijay
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-----
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PionLT Low Q2 LT-sep
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- mostly busy with paper
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- made a table summarizing systematic uncertainty studies for Q2=0.375
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- long row of columns of %changes in separated xsec vs t-bin
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- *NB* Garth will take a look and discuss with Vijay offline on how to use
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this info to compute systematics
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Nathan
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------
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PionLT LT-sep
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- Q2=5.0 W=2.95 mid-eps left-SHMS analysis
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- using Nacer's PID code, modified for pion sutdy
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- plot of RFtime vs MM clearly indicates it cannot be used to separate pi,K for
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this setting, the time offset between them is too small to be useful
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- shown CoinTime plot is not properly centered at 0, cuts are off
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- using ROC1, need to switch to ROC2
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- no Aerogel cut to remove protons is applied yet
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- Q2=6.0 W=3.19 mid-eps
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- replay just finished, showed fresh plots
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- CoinTime has a double peak structure, it seems that somewhere in the ~100
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runs of this setting the CoinTime offset changed
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- still lots to look at here
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Next Meetings
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-------------
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- Thurs: Apr 30 @ 16:00 Eastern/14:00 Regina
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- PionLT will go first
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- Fri: May 1 @ 11:00 Eastern/9:00 Regina
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- we will continue where we left off
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Going forward:
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- the Friday morning meeting conflicts with the new Hall C RC meeting time, so
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we need to move at least the Friday meeting
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- please fill out the poll at:
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https://www.when2meet.com/?36401043-97RnM
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