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Mar 28/24 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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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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Regina  Garth Huber, Ali Usman, Alicia Postuma, Muhammad Junaid,

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Nathan Heinrich, Nacer Hamdi

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York  Stephen Kay

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JLab  Dave Gaskell

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CUA  Richard Trotta, Tanja Horn

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CSULA  Konrad Aniol

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Richard

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RF TOF correction

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 discovered an issue in xptar, xptar distributions for physics data

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 Heep data had good similarity between data and MC xptar, yptar

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distributions

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 p(e,e'K+)L had similar MC xptar, yptar dists than Heep, but physics data

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dists were different than expected

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 investigated whether this was optics issue, etc. and finally tracked the

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problem to originate from the RF cut

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 the issue is that there is no TOF pathlength correction to the RF time,

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giving a correlation between xptar, yptar and RF time

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 the RF cut (for low epsilon K+ data) was too tight, and removed events at

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edges of TOF distribution

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 the RF distributions for K+ and pi+ overlap strongly for higher Q2 data, so

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the RF cut is not all that effective for these events

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 relying on pion subtraction anyways, so probably will not use RF cut for

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these data

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Nacer

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Low Q2 KaonLT PID analysis, Q2=0.5, W=2.40 THshms=9.79(left)

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 for these data, the RF time cut is remarkably effective

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 plot of RFtime vs MMk shows a large separation between K+Lambda, K+Sigma and

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pi+Delta events

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 plots of K+Lambda yield and K+Lambda/\sqrt(sig+bkd) vs (>RF cut) show a

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stable plateau for some ranges of cuts, ~1.051.2

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 plot of MMk for various types of cuts:

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 using all other PID cuts but no RF cut, still lots of pi+ bkd underneath

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K+Lambda and K+Sigma peaks

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 using only RF cut, no other PID, pi+ are highly suppressed

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 comparison of K+Lambda yields for various cuts indicates that we can get rid

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of all SHMS PID cuts and keep only RF cut, reduction in K+Lambda peak counts

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is minimized in comparison to bkd, with additional SHMS PID cuts the K+Lambda

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peak yield also is decreased

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 Dave: is the SHMS momentum low enough to rely only on SHMS_beta?

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 NH shows beta distribution plot, and MMk using beta cut, clearly not

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effective for distinguishing pi+ from K+

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 Clearly for Nacer's analysis we need to deal with the RF TOF correction

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identified by Richard

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 Stephen had tried implementing the TOF correction from the CoinTime,

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unfortunately it was not successful (the TOF correction seemed to go the

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wrong direction, made the RF worse instead of better), and not pursued

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further

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 Stephen has two blocks of code where he was trying various things:

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One block is at:

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https://github.com/sjdkay/hcana/blob/d4c646ecc46b99bfd610669f57047c4e8a83e457/src/THcRFTime.cxx#L348

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Another big block of stuff in THcCoinTime  CT corrected RF values:

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https://github.com/sjdkay/hcana/blob/d4c646ecc46b99bfd610669f57047c4e8a83e457/src/THcCoinTime.cxx#L170

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Nacer can access some of Stephen's RF testing work on lark at:

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/d8tb3/sjdkay/JLab/RF_Class_Update_21_10_22_Tests

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 might be some pdfs with testing there. Unfortunately his notebooks are

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in York. will check when he gets back next week and forward anything on

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Ali

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pi+n Radiative Tail contribs in piDelta BSA Region

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 pi+n normalizing SIMC to data peak vs data integral

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Option 1: match pi+n peaks  use for systematics studies

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Option 2: match pi+n radiative tails  too extreme, won't be used

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Option 3: match pi+n integral  chosen default for analysis

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 integral range is 0.920.96, seems to approximately balance overheight at

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peak with underwidth lower down

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 Other fits planned for systematic studies:

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 integrate Bkd subtracted data

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 integrate piDelta MC fit to data

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 MMcut dependence

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Alicia

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pi+n BSA results w/ delta_SHMS correction now implemented

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 Q2=3.0, W=3.14, 7 tbins, data looks very nice, maybe a bit smoother than

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before (did not yet do a detailed comparison)

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 Q2=5.5, W=3.02, 5 tbins

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 Q2=4.4, W=2.74, 2nd tbin still has some phioscillation as before

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 hopes to have rest of BSA results ready by early next week

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PARTONS GPD model update

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 previously found weird statistical fluctuations in PARTONS output

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 uses a MC module, needed to increase MC calls by 10x to remove fluctuations

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 PARTONS now gives roughly the same shape as LT' data vs t, but ~3x too high

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 will rerun PARTONS again with GPD H_Tx2, as Stefan Diehl did, to improve

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agreement

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BSA uncertainty discussion

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 for systematics studies, will have 2 BSA fits, and cut adjustments to CT, MM

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 separate discussion needed to incorporate all this into errors

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 Tues Apr 2 @ 15:00 Eastern/13:00 Regina/12:00 Calif

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Zoom ID: 991 7509 1967

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Passcode: 225211

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Nathan

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PionLT Lumi analysis

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 modified RT's scripts to get them working for PionLT

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 added some dummy=1 flags for HMS when doing SHMS only

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 getting some weird results:

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TLT~4000% for Carbon Runs 1673816746

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 running times are very nearly zero

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 most events apparently are excluded by beam current cut

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 BCM not calibrated for these runs yet

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 Dave Mack can do BCM calib for this one run next week

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 NH can do other BCM calibs if DM gives instructions

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 other aspects do look good:

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 CPULT looks reasonable

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 SHMS trackeff ~99.88%, seems suspiciously too good

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 Richard: there are some hard coded corrections and cuts in the script you

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need to watch for

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Junaid

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PionLT Heep Coin study (9 settings)

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 applied same cuts to Data & SIMC

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 BCM calibs not yet done, as noted by Nathan

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 made plots of PMX,Y,Z,EM,W for inplane offsets

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 all beam energies show same trends, unlike KaonLT

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 hopefully this means that all 9 settings can use the same offsets, will see

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 GH asks for some plots to have finer binning so that peak centroids are

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more accurately defined

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 next steps:

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 HMS Calorimeter and Cherenkov efficiency studies

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Stephen

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Reminder to send comments for York NSTAR* conference abstract

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Next Meeting

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 Thur April 4 @ 15:00 Eastern/13:00 Regina

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 PionLT will go first

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 Also don't forget about the dedicated BSA uncertainties discussion

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 Tue April 2 @ 15:00 Eastern/13:00 Regina

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