Kaon_LT Experiment

                Oct 16-17/25 PionLT/KaonLT Analysis Meeting Notes

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                                (Notes by GH)

                    Today: PionLT will be discussed first

Please remember to post your slides at:

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

Thursday: Present

-----------------

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

   Nermin Sadoun

FIU - Pete Markowitz

Virginia - Richard Trotta

CUA - BC Manoj

Ohio - Julie Roche

JLab - Dave Gaskell

Nathan

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PionLT - wrapping up CoinLumi study

- evaluating EDTM Total Livetime systematic uncertainty

  - ROOT refused to fit an exponential to EDTM_TLT vs CoinRate, so kept to a

    logarithmic fit

  - does a separate fit for each study and plots residuals of EDTM_TLT-fit

  - resulting histogram is slightly asymmetric

  - standard deviation 0.55%

- *NB* Dave: concerned that the scatter in EDTM_TLT at constant CoinRate for

   various settings means this is not the right variable.  Suggests a method

   that should not depend on choosing the right variable

   - plot NormYield vs CoinRate for each CoinLumi setting separately

   - fit CoinRate with only a constant, should be the same as the simple

     Error-Weighted_average of the NormYield data

     - then renormalize each NormYield with this constant, so that the weighted

       average for each setting is unity

     - make a histogram of the residual NormYield-1 and find the standard

       deviation

   - Garth: concerned that this will double-count the statistical error,

     i.e. this distribution will include statistical uncertainty of these

     points in addition to systematics.  What we want is only the systematic,

     which we can apply to the physics data in addition to the statistical

     error

     - Dave suggests a modification:

       - look at the consistency of ChiSquare with 1 for each setting

       - if the ChiSquare is 1, this would indicate only statistical errors and

         we could argue that there is no additional systematic

       - any deviation ChiSquare>1 would indicate a systematic uncertainty

- Additional detail on the CoinBlocking correction:

  Denominator makes use of the cut:

    CoinBlocking_Total  CTime.CoinTime_RAW_ROC2 > -150 && CTime.CoinTime_RAW_ROC2 < 250 && ALL_COIN_events && H.hod.goodstarttime == 1 && P.hod.goodstarttime == 1 && H.dc.ntrack > 0  && P.dc.ntrack > 0

  Numerator uses:  

    CoinBlocking_Good   CTime.CoinTime_RAW_ROC2 > 20 && CTime.CoinTime_RAW_ROC2 < 140 && ALL_COIN_events && H.hod.goodstarttime == 1 && P.hod.goodstarttime == 1  && H.dc.ntrack > 0  && P.dc.ntrack > 0

  where ALL_COIN_events is: g.evtyp >= 4 && g.evtyp <= 7 

  - This selects only coin events and makes sure that there was good signal in

    both hodoscopes and drift chambers.

    - i.e. events with CoinTime=10^38 are removed

  - apparently the issue is that some prescaled singles come into the COIN

    stream by mistake.  The DAQ trigger logic really needs to be reporgrammed to

    allow such double counting

- modifications made to Report Files for CoinBlocking correction

  - beam current offset and its uncertainty applied correctly now

  - LH2 boiling correction uncertainty also in report file

Junaid

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PionLT Q2=3.85 LT-sep

- tested Nathan's replay changes, seems OK

- replaying Q2=3.85, W=2.02 setting for next LT-separation

- still working on TT model for W=2.62 LT-sep

  - still see double-bump oscillation in Data/MC ratios

Alicia

------

pi+ BSA PLB updates

- Haiyan Gao had a staff member help with the resubmission

- the paper is now submitted, but the references are corrupted

- Alicia contacted the staff member and Haiyan on getting the references fixed,

  but no reply

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Friday: Present

---------------

Regina - Garth Huber, Alicia Postuma, Vijay Kumar, Nacer Hamdi,

   Nermin Sadoun, Muhammad Junaid

Virginia - Richard Trotta

JMU - Gabriel Niculescu

JLab - Dave Gaskell

CUA - Sameer Jain, Tanja Horn, Chi Kin Tam, BC Manoj

FIU - Pete Markowitz

Ohio - Julie Roche

Glasgow - Kathleen Ramage

Richard

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KaonLT Q2=4.4, W=2.74 LT-sep

- functional forms had no Q2-dependence in them

- now scaling L/T/LT/TT terms by (Q^2_event/Q^2_central)^n

  where n= -2.18(L) -1.89(T) -2.01(LT) -2.34(TT)

Chi Kin

-------

KaonLT high Q2 data analysis

- Q2=4.4, W=2.74

  - compared MM data after PID cuts with Richard's analysis

    - no acceptance, HGC hole or diamond cuts

    - the distributions look identical

  - then compare NormYield/mC with Richard

    - has some significant differences in some (t,phi) bins

    - investigating what is different, will check the diamond cuts

- Q2=3.0, W=3.14

  - undid shift in SIMC MM distribution

  - adjusted t-bin width

  - compare HMS distributions for Data and MC

    - weird SIMC distributions observed earlier was due to unphysical

      cross-section values at large -t

    - now applied a t-cut to restrict SIMC to the range of the data

    - agreement looks much better now

  - still running into bad parameter fits for TT term

    - changed from p4/(|t|^p5)*exp(-|p6*t|) to p4*exp(-p5*ln|t|-|p6*t|)

    - not working well, needs to look into some other form

    - Garth: taking the exponential of a logarithm seems weird

      - *NB* suggests to try simply checking with a calculator some functional

        forms and see what might be more promising, rather than random changes

Sameer

------

KaonLT CoinBlocking correction

- following Nathan's steps

  - revised CTime.CoinTime_RAW_ROC2 cut values: -20 to +80

    Q2=2.1, W=2.95, high epsilon, center SHMS runs 4891-4912

    - most runs have correction ~0.9, but there are some weird outliers with

      correction ~0.7, and a sharp shift in correction at rate ~2.5kHz

  - *NB* Richard: cut still looks too tight, suggests to increase to +110 and

    also loosen negative side

  - *NB* need to investigate the outliers and the sudden shift

  - also need to add the loose denominator cut that Nathan mentions above

Vijay

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PionLT Summer 2019 CoinBlocking correction

- also following Nathan's steps

  - using a 135ns wide cut, the trigger oscillation traces have 140ns

  - the cut looks slightly generous but should be good

  - correction factor ~0.9, with high epsilon ~0.95 and low epsilon at 0.88

  - for denominator, will apply a wide cut -600 to +900

Nacer

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KaonLT Q2=0.5 LT-sep

- last week, had Data/MC ratios near 1 but with double-bump oscillations at

  high epsilon

  - the fit model had LT=TT=0

- now trying TT=(p7*exp(-p8*|t-tmin|)/((Q^2+p9)^2)*sin(thetacm) and similar

  function for LT

  - ratios get much worse after 3 iterations, oscillations continue to grow

- Dave: all analyses are encountering interference function problems, is

  there an inconsistency in how phi is calculated between hcana and SIMC?

  - Richard: all recon_hcana calculations applied to SIMC are taken from hcana

    xq = fX.Vect();

    bq = fB.Vect();

    xq *= rot_to_q;

    bq *= rot_to_q;

    //Calculate Angles of q relative to x(detected proton) and b(recoil neutron)

    th_pq = xq.Theta(); //"theta_pq"

    ph_pq = xq.Phi(); //"out-of-plane angle", "phi_pq"

    th_nq = bq.Theta(); // theta_nq

    ph_nq = bq.Phi(); //phi_nq

    thetapq = th_pq;

    phipq = ph_pq;

    Richard's version of recon_hcana at:

    https://github.com/trottar/simc_gfortran/blob/LTSep_Analysis_2024_kaon_xsects/recon_hcana/recon_hcana.C

  - Gabriel: it's important to verify that data and SIMC phi distributions are

    the same

    - Nacer looks up a comparison histogram, they indeed look identical

  - Dave: maybe there's an inconstency between how phi-vertex used in the model

    is calculated compared to phi-recon used in the iterations?

    - *NB* Garth: suggests to make a plot comparing phit from SIMC with phi

      from recon_hcana.  Expect to see a difference in resolution because phit

      is the truth variable, but they should not differ in gross features

    - *NB* Dave: suggests to apply recon_hcana script to phit when calculating

      model cross sections in SIMC

- *NB* Dave: looking at Richard's version of recon_hcana

  - this version has cuts in it, was not expecting to find any cuts there if

    this is for general use

- *NB* Gabriel: this version also has offsets applied in it, what happens if

    the offset is applied repeatedly in each iteration, that would cause huge

    problems

   - it's better to apply the offsets in a transparent fashion rather than

     being in this code, to avoid them being applied more than once

- Richard:

  I uploaded a clean version of my recon_hcana script to my master

  branch. There is only the hard coded kaon mass in this version (just search

  'HARD CODED' in cpp script).

  https://github.com/trottar/simc_gfortran/tree/master/recon_hcana

  If anyone finds any other issues or if we'd like to add calculations for the

  vertex variables let me know. These variables are already defined

  (unchanged), but easy enough to recalculate.

  It is also easy to add new versions of variables (e.g., phipqi->phipqi_test)

  for comparisons. New variables just need to be initiated in the header, added

  as a branch, then calculated in the loop in the cpp file.

  - *NB* it's important that everyone double check their version of recon_hcana

    compared to this clean version!

BC Manoj

--------

- still learning how to replay data, no report yet

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Next Meeting

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New 2-meeting/week structure

- Thurs: Oct 23 @ 16:00 Eastern/14:00 Regina

  - KaonLT will go first

- Fri: Oct 24 @ 11:00 Eastern/9:00 Regina

  - we will continue where we left off