Kaon_LT Experiment

                 Feb 15/24 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, 

   Alicia Postuma, Nacer Hamdi

JLab - Dave Gaskell

York - Stephen Kay

CUA - Casey Morean, Richard Trotta, Tanja Horn

FIU - Pete Markowitz

CSULA - Konrad Aniol

Richard

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Updated Efficiencies

- needed to fix used HMS Cherenkov and Calorimeter Effs in Effective Charge

  script

  Now using: hcer eff=0.9730 unc=0.0006

             hcal eff=0.9961 unc=0.0005

Fixed issue with Data/MC average ratios script

- was over-writing ratio values w/ just ones from Center Setting in

  average_ratios.f

  - this means Left and Right settings were not included

  - of course this makes a big difference to the phi-coverage at higher -t

- a short discussion followed on the optimal number of t,phi bins to use, how

  many is too many?

  - the important issue is to have sufficient statistical significance to

    distinguish a potentially small sig_L from zero

  - From the online KaonLT statistics, GH had estimated #t-bins (K+Lambda):

    Q2=0.50  x=0.09  5 t-bins

       2.115 x=0.21  5 t-bins

       3.00  x=0.25  5 t-bins

       3.00  x=0.40  2 t-bins

       4.40  x=0.40  2 t-bins

       5.50  x=0.40  2 t-bins

    This is only an approximate guide, might need fewer bins to have good

    L/T-separation

  - using 10 phi bins now.  Seems appropriate.  pi+ channel can probably use 16

    bins.

Corrections to calculation of statistical uncertainties

- had a long discussion w/ Ali, a second meeting with GH

- reviewed equations from T.Horn and W.Li theses

- for Q2=2.115 delta-R_bin: 5-10%, and dY_data_bin~dY_simc_bin

  - surprised SIMC errors aren't smaller, given #evnts generated, will

    investigate further

Aerogel/HGC cuts in SIMC

- aerogel tray cut applied in recon_hcana, while HGC cut is applied in

  lt_analysis

  - the HGC cut is arranged this way to be more consistent w/ data analysis

- comparing data & SMC x,y_HGC plots w/ hole cut

  - sees a 10cm X-shift in HGC cut compared to Vijay

    GH: perhaps RT and VK are projecting to different z_HGC locations?

Pion/proton leakage subtraction script

- GH: need to use pi+ data instead of simulation, since the K+L peak lies above

  the Delta0pi+ and inclusive region, pi+n simulation would only include

  radiative tail and none of these other contributions, would then have to run

  multiple SIMC generators to get all of the contributions, making for a much

  more complicated fit

- This is even more important for K+Sigma extraction!

Unseparated XSect systematic studies

- met with TH to discuss systematic error table

- nice table listed on what cuts to vary for each systematic study

  Tracking: compare pruning and chi-square methods

  Acceptance: vary acceptance cuts

  PID: compare high, low epsilon HGC hole cuts

  Kinematics: vary angle, momentum, energy offsets

  MC Model: vary fit model parameters from final iteration values

  Radiative Tail: SIMC w/ and w/o rad flag

Issues w/ generating new parameterization

- now that L,R,C ratios issue fixed, things starting to look good

- initial indications is that t-dependence in the model is wrong

  - will try removing t-dependence to sigT

Ali

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Optimizing SIMC MM resolution

- high epsilon 10.6GeV data have worst resolution mismatch

- using data dists from most recent full pass replay, incl TOF-CT leakage

  correction and offsets

- SIMC also offset corrected

  - initial plots only for SIMC resolution tuning

  - Dave's delta correction not included

- shows plots for central settings only, expect L,R to be very similar

- one SHMS resolution tuning parameter used for all kinematics

  - Q2=3.0 W=2.32 HMS=6.58 - mismatch is fairly large here

  - Q2=5.5 W=3.03 HMS=3.26 - best resolution agreement

- shows t-binned Q2=5.5 plots from Alicia

  - overall, the agreement is better now

  - definitely see a t-dependence to the discrepancy, so the t-binned plots

    will be vital for determining a final correction

- added HMS DC resolution correction from Abhyuday

  - didn't see any significant improvement for Q2=3.0 W=2.32 center

- DG: how much is the SHMS resolution changed by?

  - a multiplicative factor is used in SIMC, 9x

  - seems very high!

- Nacer: asks some questions about the pi+n SIMC model

- GH: it would be valuable to check 1-2 low epsilon settings where P_HMS is

   lower

- Nacer: any final discrepancy between data and MC agreement should end up

   being quoted as part of the Model systematic error

   - GH agrees with this

Alicia

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Recap of BSA analysis status

- need to implement Dave's delta-correction and troubleshoot

- then rerun BSA calc, mean kin, cut dependence scripts

- will arrange a separate future meeting to discuss error propagation

- then finalize Q2-scans at fixed xB including Hall B data

- goal of distributing draft paper by end of March

Troubleshooting delta-correction

- delta_corr=hsdelta+6.0*hsxpfp

- Problem: finding that MM resolution w/o correction is worse than from hcana

  - DG: to do a quick check, used an old script which calculated MM like old

    6GeV ENGINE

    - should use Richard's recon script instead, which has same MM formulas as

      hcana

    - the issue is that hcana has improved corrections for xtar dependence

      compared to ENGINE, since longer target lenghts are used in 12GeV running

      compared to 6GeV

- sees an improvement when the delta-correction is applied, but will need to

  redo the study due to different MM calc than hcana

  - Ali will also have to retune SHMS resolution study after Alicia is done her

    study

- Alicia's t-binning plots at Q2=4.4 shows that Ali's 9x resolution factor is

  too big

  - would like SIMC to never be wider than data, for any t-bin

Nacer

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DC calibs

- pushed changes to GitHub

  - Junaid should check things over before accepting

  - maybe Ali can look things over as well, as he's more familiar with KaonLT

    layout

- hoping to submit full replay over weekend

Nathan

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- catching up on things after being RC

- BCM param map now set up

- hoping to have some Lumi plots next week

  - will start with the robust singles study from end of PionLT run

Junaid

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Tracking Eff study

- plots of EDTM, Elec_sing_TrkEff, Elec_COIN_TrkEff, Hodo3/4Eff for HMS

  - a small number of outlier runs (eff=0) that need checking, but overall

    looks good, with reasonably tight, monotonic trends vs rate

- similar plots for SHMS

  - also a few outliers that need checking

- pTRIG6 runs for HMS also shown

  - these were for the ELREAL trigger efficiency study

- HeepCoin data plots

  - plot of SHMS >1MHz Hodo rate shows sharper drop off of eff at very high

    rate

Next Meeting

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- Thur Feb 22 @ 15:00 Eastern/14:00 Regina

  - PionLT will go first