## Kaon LT Meetings » mtg_24feb22.txt

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Feb 22/24 PionLT/KaonLT Analysis Meeting Notes |
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---------------------------------------------- |

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(Notes by GH) |

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Today: PionLT 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 - Nathan Heinrich, Garth Huber, Ali Usman, Alicia Postuma, |

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Muhammad Junaid, Nacer Hamdi |

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CSULA - Konrad Aniol |

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CUA - Richard Trotta, Tanja Horn |

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York - Stephen Kay |

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FIU - Pete Markowitz |

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Nathan |

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------ |

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Writing Lumi analysis script for PionLT |

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- modifying script from Richard, which always assumed an active HMS and SHMS |

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trigger for each run, as some PionLT Lumi scans were single arm only |

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- had to make similar edits earlier for CoinLumi script, so confident of the |

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needed changes |

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- edits made, still testing |

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Script for plots for SHMS NIM paper |

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- started to modify old plotting script |

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- looked briefly so far at the draft NIM paper text |

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- once the plotting code has been run, will look up needed details for the |

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paper |

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Junaid |

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------ |

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PionLT efficiency studies |

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- investigating outlier runs identified last week, about 30 runs in total |

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- will make some decisions soon on which runs to discard |

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- then will post efficiency slides on RedMine |

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Ali |

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--- |

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SIMC resolution study |

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- on hold until Alicia finishes HMS delta-correction study |

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Setting up for pi+n LT-analysis |

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- replayed 3 of 5 settings so far (both epsilons) |

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- of these, analysis completed for 2 of 3 settings |

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- will give Richard clean pi+n data for subtraction |

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- updated SIMC w/ physics_iterate.f model |

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- compared to Vijay's code, almost identical except for different Q2-settings |

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- looking at Richard's LT-sep scripts, hoping to have some initial ratios soon |

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Info re HGC cut issue |

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- no HGC cut intended to be used for pi+n analysis, get a small K+L leakage, |

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but in MM region well above pi+n |

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- this means pi+n analysis will also not need an HGC efficiency to be applied |

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- on the other hand, pi+Delta0 region is affected by K+L leakage, and will |

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need an HGC cut as well as an HGC efficiency to be applied |

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- the pi+ sample for Richard will not have an HGC cut applied |

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- will give skimmed ROOT files w/o HGC cut to RT, he will have to apply the |

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HGC cut before subtracting pi+ leakage sample from K+ data |

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Richard |

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------- |

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Comparing SIMC model to preliminary data |

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- looked at 4 of 6 settings (including Q2=0.5) |

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- Q2=0.5 has lots of issues that he will flag for Nacer to eventually look at |

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- standard.kinematics issues: |

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- need to confirm that CoinTime offset is set correctly for EVERY run |

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- SHMS_RF_Offset was also not set for some low Q2 runs |

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Initial look at Q2=2.115, W=2.95 |

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- all LT, TT terms set to zero for now in model |

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- sigL model: adjusted exp(|t|-0.2) factor to exp(|t|+0.2), seems to give more |

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stable ratios vs t |

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- sigT model: compared p5+p6*log(Q2) with alternative p5*log(Q2)+p6/Q4 |

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- also compared to Tanja's global K+ analysis in PRC 85, 018202 (2012) |

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- checked W-factor and sigT models in this paper |

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- W dependence: tried changing W-factor=1/(W2-Mp2)^2 to 1/(W2-Mp2)^3 |

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- Tanja's paper has the power as 2.5 |

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- when changing the W-factor, found that the sig_UNS expt error bars changed |

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a lot, which should have not happened |

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- this indicates a coding error that needs fixing |

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- then tried sigT=p5/(1+p6*Q2) and old W-factor |

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- manually changing p5 from 120 to 25 gave better ratios |

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- doing things by hand right now, instead of using MINUIT to get new params |

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Initial look at Q2=3.0, W=3.4 |

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- same procedure, changing sigT and sigL factors |

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- lowering sigT p5 param improves ratios, just as at Q2=2.115 |

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- *WARNING* data have NO MM-cut applied at all, not only do the exp yields |

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contain pi+ and proton leakthrough, they also include all K+ contributions |

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from inclusive spectrum above Lambda peak |

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- right, now sees a weird phi Left-Right asymmetry in the data |

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- the experimental yields will CHANGE SIGNIFICANTLY once Richard has a clean |

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sample |

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- Ali offers to generate for Richard also a clean proton sample for subtraction |

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Initial look at Q2=3.0, W=2.32 |

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- looked at using W-factor with ^3 exponent |

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- getting negative sigL for lowest -t bin, CAVEATS in data as above |

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Compared initial results vs x_B |

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- early indications that a systematic change in the model vs x_B will be |

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needed, will be interesting if this holds up in more thorough analysis |

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GH: as a reminder, we will eventually have to look again at the residual |

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Q2-dependence of the Heep-Coin ratios, and resolve this issue before we can |

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finalize the data and publish |

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- this should happen after Richard graduates |

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Alicia |

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Implementing HMS delta-correction, hsdelta_NEW=hsdelta-p0*hsxpfp |

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- took MM calc from Richard's reconstruction script and implemented calc for |

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data |

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- as a check, compared new MM calc w/p0=0 to old MM calc |

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- overall very similar, but a slight difference between them |

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- plot difference in #events vs Mx, most pi+n events within +/-2 MeV compared |

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to old MM calc |

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- best guess is that there is some rounding error difference in the HMS |

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momentum calc compared to hcana when applying offsets |

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- GH: as a coding check, can try comparing old and new MM w/o offset |

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- then applied Dave's p0 values and compared the old-new data |

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- MM gets wider instead of narrower, something still seems wrong |

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- GH: suggest to make a plot of hsdelta_NEW vs hsxpfp to see what kind of |

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correlation you get, should be a straight vertical band if applied |

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correctly |

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- Alicia will send her script to Richard for review |

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Nacer |

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----- |

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Low Q2 KaonLT calibs |

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- finished DC and Hodo timewalk calcs |

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- pull request to GitHub was accepted |

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- did a full replay, including all of Ali and Richard's improvements |

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- plot of EDTM vs Coin_trig_rate |

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- sees sharp drop off above 2.7kHz trig rate, as expected, due to buffered |

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mode data acquisition (good news) |

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- plot of COIN_CPULT vs COIN_trig_rate |

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- similar behavior, looks good |

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- plots of HMS(e), SHMS(pi) SING_TRK_Eff vs S1X hodo rate |

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- no HMS outliers |

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- a few SHMS outliers that need investigation |

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To Do: |

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- check other plots |

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- move to K+ PID |

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- also should get Lumi scripts from Richard and look at Low-Q2 Lumi scans |

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Next Meeting |

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------------ |

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- Thur Feb 29 @ 15:00 Eastern/14:00 Regina |

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- KaonLT will go first |

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