Kaon_LT Experiment

                 Dec 21/23 PionLT/KaonLT Analysis Meeting Notes

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                              (Notes by GH)

                     Today: KaonLT will be discussed first

Please remember to post your slides at:

https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings

Present

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Regina - Garth Huber, Ali Usman, Muhammad Junaid, Nathan Heinrich, Vijay Kumar,

   Nacer Hamdi

JLab - Dave Gaskell

FIU - Pete Markowitz

CUA - Richard Trotta, Tanja Horn

Richard

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Weight iteration script for LT-separations

- working on script to fit separated cross sections to get parameters for next

  iteration, other parts done

Heep analysis

- made a nice table of efficiencies and associated uncertainties for Heep and

  Physics data analysis

- HGC cuts to select K+ after discussion with Peter Bosted:

  - place a cut around HGC hole to reduce pi+ leakthrough

    - *NOTE* will need to place SAME CUT on SIMC

  - place a NPE<1 cut to eliminate pions

    - DG: the cut can be fairly tight since K+ are below HGC Cherenkov

      threshold, there will be NPE from knock-on electrons, but it shouldn't

      make too much difference whether the cut is at 1 or 2 NPE

    - *NOTE* will need to find the correction factor (a few %) for the K+ with

      knock-on electrons that are removed by this cut

- Calorimeter Efficiencies per spectrometer setting, not beam energy

  - DG: need a dedicated study to determine these efficiencies, not from the

    report files

  - AU: this study was done earlier.  Looked at Heep singles data w/low pi-

    contamination

    - some Heep settings had P_HMS above Cherenkov threshold, and could not

      be used

    - DG: the efficiency should plateau for momenta > ~3 GeV/c, it would be

      okay to extrapolate this number to higher momenta above the Cherenkov

      threshold, the issue is the efficiency at very low HMS momenta

    - DG: need a fit or lookup table for efficiency vs P_HMS

- Heep Data/MC yield ratios

  - when removing HGC cut on Heep analysis, W shifted by ~0.1 MeV, this affects

    data/MC yield comparison

  - Yield ratios have a linear trend vs. Q2 that needs more investigation

    - no error bars are plotted yet

    - suggest to have simple PID cuts for Heep COIN since so clean, try to

       make the analysis as robust as possible

  - Vijay has a much flatter yield ratio plot, so the difference needs to be

    understood

    - GH+TH: Vijay and Richard should communicate by email on exactly what cuts

      and efficiencies are applied to the Heep data, so the major parts of

      their analyses can be compared

- LH2 boiling correction

  - discussion about the calculated uncertainties and how they should vary with

    current, RT gets a surprisingly large increase in uncertainty with current

  - Eqn 5.22a,b on Boiling Correction in Carlos Yero's thesis

  - TH: Carlos' eqn is absolute error in the boiling correction, you can't

    apply this formula without modification for percentage error

Ali

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piDelta BSA

- looking into rho decay contribution, running SIMC

- working on script to combine L,C,R SHMS settings

- next will look at higher Q2 settings, and rerun SIMC w/ offsets

Dave

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Looking into MM resolution issues

- Run 4920, Q2=2.115, P_HMS=5.292 GeV/c

  - HMS-delta vs MM: see a clear linear correlation

  - HMS-delta vs xptar,yptar: also see some correlation (more complicated with

    some curvature)

  - clearly indicates some optics issues that can account for the wider MM peak

    compared to SIMC

- AU: the KaonLT replay used a dedicated set of Matrix Elements for P_HMS=6.5

  GeV/c, but nothing special for 5.3 GeV/c

- next step is to look at MM vs Focal Plane variables, to see if there is a

  linear correlation that can be removed with an ad-hoc correction

Vijay

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Low Q2 lumi and Heep analysis

- Carbon-12 HMS, Heep yields vs current

  - found a small bug in the script used to produce last week's plots

  - in addition, was previously using statistical error in EDTM study, now

    using 2% uncertainty in EDTM livetime from Carlos Yero's thesis

  - the issue is that in KaonLT, the EDTM could only be set manually from the

    electronics room.  For many runs we did not have enough EDTM events, and it

    was difficult to monitor this during the data taking.

Heep Data/MC yield ratios

- plot has a small linear dependence with Q2, but error bars at high Q2 are

  fairly large

- DG: surprised the error bar is so large at Q2=3.75

  - the run sheets show 3x40k events for this setting

  - Vijay will confirm what was done, possibly only 1 run was analyzed instead

    of all three

Nacer

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Drift Chamber calibration checks after new Hodo calibs

- still debugging DC calib scripts, trying to adapt PionLT code to KaonLT

  - discussing with Junaid

Nathan

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Coincidence Reference times

- finished on Monday, CoinTime now centered at zero and sharper for all runs

- changes pushed to GitHub

Full replay script

- working w/ Junaid on the script and checking

Junaid

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- merged all Nathan's changes to GitHub

  - everything is set up, but problems on including Helicity variables in

    replay

  - Ali can point to which script to use

- All Events No EDTM for all runs except Lumi, which will be All Events

- hope to submit full replays soon, and will monitor them over holidays

After the replay is done:

- Junaid will work on Tracking Efficiencies

- Nathan will work on Lumi

  - will start with scaler and UnTracked yields analysis which are independent

    of Junaid's work

  - depending on Junaid's progress, will pivot to PID analysis if tracking effs

    not ready when needed for Tracked Lumi analysis

Next Meeting

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- Thur Jan 4 @ 15:00 Eastern/14:00 Regina

  - PionLT will go first

Hoping everyone has a good holiday.  Merry Christmas and Happy New Year!