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Oct 10/24 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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Present

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Regina  Garth Huber, Alicia Postuma, Nathan Heinrich, Muhammad Junaid,

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Vijay Kumar, Nacer Hamdi, Argha Das

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CUA  Casey Morean, Tanja Horn

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JLab  Dave Gaskell

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Virginia  Richard Trotta

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Ohio  Julie Roche

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FIU  Pete Markowitz

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Vijay

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Finalized PhaseSpace Volume Cut Systematic Study

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 varied delta_HMS cut by 10%, as discussed last week

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 calculate R=Y_DATA/Y_MC for each (t,phi) bin, then do errorweighted average

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of R of 16 phibins, for each of 7 tbins

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 R changes 15% from low to high t bin

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 quadrature sum of delta(), xptar(+), yptar(+) gives 1.2% to 6.5% from low

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to high t bin

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 Tanja: have you done any checks yet on whether the new replay is the same as

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this or different? It would be good to not waste time by having to repeat

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the study if the new replay is different?

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 files directly from hcana replay were lost, files after python analysis

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were correctly archived

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 replay of Q2=0.42 should happen next week, first have to modify replay

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scripts for ALMA9 then submit

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 will replay Q2=0.38 at same time, still have to check that results are

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unchanged

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 Garth: it will be important to archive the code used to generate the results,

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including the replay scripts

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Alicia

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Response to Referees on BSA PRL draft

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 key authors promised to give feedback on the response letter, as well as the

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manuscript, no later than Monday

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Nacer

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KaonLT Heep singles analysis

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 ran singles replay after lots of help from Junaid

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 still debugging results

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Nathan

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PionLT Luminosity scans (COIN SIDIS and exclusive pi+)

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 initial results shown, but still have to refine cuts and implement random

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subtraction

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 remove goodscinhit==0 cut

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 remove hgc>1.5npe cut, as protons giving knockon electron Cherenkov signal

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will give a rate dependence

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 remove betacut, as we discussed a few weeks ago

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 issues seen with CPULT

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 Exclusive: number OK but errors weird

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 SIDIS: CPULT up to 300%, so wrong variable somehow used in calculation

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 SIDIS#1 COIN yields, LH2 1220012216

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 antiboiling LH2 seen for scaler, notrack and track analyses, but should

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look better after randoms subtracted

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 SIDIS#2, LH2 antiboiling is less

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 Excl#1,3 LH2 1460114606, 1581615846

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 notrack is flat, will go down after random subtraction

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 track has 20% boiling, which is larger than SIDIS (~10%)

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 Excl#4,5 1622016242

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 similar to Excl#1,3

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Junaid

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Hodo3/4 efficiencies

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 Mark Jones made significant changes to hcana code which seem to have fixed

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the issue, now getting ~99% efficiency for both Heep and Physics data

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 recompiled hcana for both PionLT and KaonLT, so everyone has access to the

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changes now

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 still investigating exactly what Mark changed, but as a summary:

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 modified module for event selection used to calc Hodo3/4 Eff

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 need to add parameters to "phodo_cut.param" file

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 essentially, events w/HMS singles need to be removed when calculating

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SHMS efficiencies

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 added module to check missing track positions, fTrack_Miss_Xpos, Ypos

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 added goodstarttime cut

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 with the new efficiencies, Heep ratios are 0.951.013, excluding one outlier

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setting with R=0.85

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 Richard's boiling correction is applied, awaiting result of Nathan's

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analysis

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New HMS matrix elements

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 Christine will release 5.6 GeV/C ME in ~1 week

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 5.9 GeV/c is half done so far, should also not be long

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 4.9 GeV/c is planned to be analyzed, apparently some evidence of saturation

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already there

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 6.8 GeV/c, unsure of ME fitting status

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PionLT pi+ PID studies in progress

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 looking at 3 settings, one of which has Theta_SHMS=5.50deg

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 iterating over RF, CoinTime, Aerogel, HGC cuts to understand particle

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distributions and efficiencies

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Richard

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KaonLT L/Tseparations

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 varying exponent "n" in 1/(W^2mp^2)^n factor in cross section

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parameterizations

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 varies with increasing W, from n=3.40 at W=2.32 to n=2.25 at W=3.14

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 also trying two different TTparameterizations

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sigTT=(p13*Q^2 * exp(Q^2))*ft*sin^2(theta)

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sigTT=(p13*t+p14)*t^(Q^2/p15)p16*Q^2

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 more complicated expression generally does better, but there are few tbins

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so it is difficult to constrain so many parameters

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 Garth: suggests to figure out which parts of the complicated expression are

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more important, and simplify the expression to just that part

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 also can play the strategy of fixing some parameters and releasing others

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in the fit, and then fixing them and releasing the others. The downside

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is that it takes many more iterations to converge, but it helps avoid the

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issue of too many degrees of freedom in the fit

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 Ratios after 5 iterations are generally near 1 now

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 Q2=4.4: Ratio drops linearly with t

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 sig_UNS is consistently higher at high epsilon than at low epsilon now,

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which is very good news

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 will arrange a meeting with Garth and Tanja next week to discuss the ratios

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in more detail

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Next Meeting

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 Thur Oct 17 @ 16:30 Eastern/14:30 Regina

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 PionLT will go first

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