Kaon_LT Experiment

                 Mar 30/23 PionLT/KaonLT Analysis Meeting Notes

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                           (Notes by GH and SJDK)

                    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 - Stephen Kay, Garth Huber, Muhammad Junaid, Ali Usman, Alicia Postuma,

   Nathan Heinrich, Vijay Kumar, Love Preet

JLab - Dave Gaskell

CUA - Richard Trotta, Tanja Horn

Richard is unfortunately ill with COVID-19, and has no report

Neither Julie nor Jacob can attend today

Ali Updates

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Started to look at PID other KaonLT pi+ settings

- Central setting from Q2=2.1 high epsilon last time

- Left and right now, as well as low epsilon settings

- Analysing Q2 = 3.0, high and low eps now too

Met and discussed with Richard and Alicia last Friday regarding too-high

weirdness with right setting

- Alicia will give update

Alicia Updates

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Right SHMS setting weirdness, using pi+ KaonLT data

- initially didn't see Right setting dominate, unlike Richard, but then

  loosened cuts and sees Right is indeed larger yield

- Plotted only acceptance cuts, with no PID, to see right setting dominate

   - pi+n MM cut took care of most of the yield differences, so it looks like a

     PID cut issue

- Good news, it's Not a replay issue, Richard and Ali's replays are consistent

   - NH: Were plots charged normalised?

      - No, showing raw plots

   - RT: I checked the charges but they were about the same

     RT also applying pid but it's pion pid vs kaon pid so something weird

     is going on with the kaon pid for right setting

- The right setting has issues because it's closer to the beam line, more

  background junk

   - VK: Is it an issue that the right has higher yield?

      - GH: Yes, it's just garbage yield that we need to understand and clean up

   - RT: I believe we won't be able to fix this until we do the pion background

     subtraction because the proton peak is massive.

      - K+ PID is more challenging than pi+ PID

      - will need to do a pi+ subtraction before comparing L,R,C yields again

   - GH: to avoid undue cut-dependence, it's better if K+ cuts are not so deep

     that we have to apply a large cut-inefficiency to correct for K+ that

     don't make the cut, in that case it's better to do a pi+ subtraction

      - can make pi+ cuts tight to get the pi+ leakage spectrum, since we are

        only interested in the MM distribution shape, not the absolute

        normalization

      - this will have to be done separately for each (t,phi) bin!

- RT/AU will meet again once RT recovers from Covid and can talk again, will

  discuss HGC inefficiencies and pi+ leakage spectrum for K+ PID and K+ leakage

  spectrum for pi+ PID

Vijay Updates

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Switched pion routine in SIMC -> physics_iterate.f instead of physics_pion.f

- Re-ran SIMC to simulate reaction for all settings of the Q2 = 0.38 setting

- SHMS xptar and yptar overall look ok, edges match up quite well

- Working on comparing other variables

   - Want to compare Phi_pi variables bin by bin for each t-bin

   - General agreement is good, distribution shapes seem to have better

     agreement with data than default pion generator

- SIMC was only arbitrarily scaled by under a factor of 2 for earlier

  plots. Not a bad agreement at all for this point.

- GH: Good news.  Almost ready to go back to yields then

   - if Heep offsets determine that a beam energy offset is needed, then will

     have to rerun SIMC, but that's not a huge problem

- VK: Work pushed daily to GitHub. Richard/Ali can grab as needed

- Still modifying some elements of Bill's code, primarily plotting scripts now

   - 3 Epsilon modifications still needed

Nathan Updates

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Slides for GHP

- Slide 3 TH: An image would be good here, lots of text, can grab a standard

  sort of image

   - GH will try to find something from an old talk by Rolf

- Slide 5 - will make a new handbag diagram with momenta labeled

- Slide 6 TH: A table with kinematics of the different experiments would be

  great, Q2 ranges, etc

   - Each cell with a different BG colour

- Slide 7 TH: make last bullet more specific, and divide into two parts

   a) if the factorization regime not reached, then cannot access leading twist

      GPDs in these experiments

   b) if sigT large, then opens the possibiity of accessing Transversity GPDs

- DG liked the log y-scale versions of the plots, as otherwise high Q2 points

   get buried along x-axis

- Slide 8 - Nathan concerned whether some statements are a bit controversial

   - GH: expect point-like behavior for mesons with heavy quarks, pion is

     relatively large meson in comparison, means heavy quark mesons should

     factorize at lower Q2 than pions

   - TH: Check some of Christian Weiss' presentations for more information on this

- TH suggests a rephrasing to improve emphasis of slide

  - if we want to establish factorization globally, need to look at multiple

    DEMP reactions

  - various other experiments have Vector Meson data, can get quasi-L/T

    separation via s-channel helicity conservation on decay products

  - need to also investigate the pseudoscalar mesons, in this case Hall C is

    the only way to get L/T-separated data

   - Rho/VM data?

      - GH: HERA has a lot of VM data, in addition to Hall B

- Slide 9 - Could be made more positive than the word "inconclusive"

   - TH: DVMP Paper - https://inspirehep.net/literature/1404915. It includes

     both vector and pseudoscalar meson data

   - the previous work was not a dedicated measurement, exploratory

   - this is the FIRST dedicated study

- Slide 11 - Make clear the L/T-separation requires different beam energies,

  which are taken at different rates

- Slide 12 - Remove map of Virginia and make a table of beam energies/gradients

  used

- Importance of phi coverage could go earlier? Right after spectrometers?

   - Need to think about ordering of various slides here a lot

   - GH: suggest to move SHMS+HMS slide earlier, leaving other Hall C

     instrumentation slides where they are

   - then can include the 3 SHMS setting slide to after L/T-sep

- Slide 17 - Clarify this is coincidence between two spectrometers

   - add CoinTime equation

   - needs to be understandable by those not familiar with Hall C

- Slide 18 - Date of expected results?

- Slide 19 - will change to log-y plots

   - need to clearly indicate that y-positions of projected data are arbitrary,

     and that the projected errors are estimated (based on obtained statistics)

- Slide 20 - Match colour of labels to colour of text in table

- Slide 21 - change "upper bound" to whatever wording is decided on earlier slide

- On thank you slide, include DoE/CUA grants

   - Get Julie's grant # etc too

- Nathan - Dry run April 5th, Wednesday

   - Will set up on Zoom so remote people can join - 15:00 Eastern (13:00 Regina)

   - Regina participants are expected to attend in person, LB 235 

   https://uregina-ca.zoom.us/j/98764326984?pwd=TVg0Uk9CY0RxL2ZSZCsxYVZCZ29oUT09

   Meeting ID: 987 6432 6984

   Passcode: 259164

Next Meeting

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- Thur Apr 6 @ 16:00 Eastern/14:00 Regina/13:00 Pacific

- PionLT will go first