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Kaon LT Meetings » mtg_23apr27.txt

Garth Huber, 04/27/2023 07:58 PM

 
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                 Apr 27/23 PionLT/KaonLT Analysis Meeting Notes
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                 -----------------------------------------------
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                           (Notes by GH and SJDK)
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                    Today: KaonLT 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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-------
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Regina - Stephen Kay, Garth Huber, Muhammad Junaid, Ali Usman, Alicia Postuma,
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   Nathan Heinrich, Vijay Kumar, Love Preet
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CUA - Tanja Horn, Richard Trotta
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Ohio - Julie Roche, Jacob Murphy
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FIU - Pete Markowitz
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JLab - Dave Gaskell, Peter Bosted
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CSULA - Konrad Aniol
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Richard Updates
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---------------
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Tracking/lumi updates
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   - Recap from 6/4/23 meeting, some runs were outside of the general trend
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      - Bad TLT?
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      - Will discuss with Jacob tomorrow about TLT calculation
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      - if the TLT calc is fine, then will need to look more closely at the
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        running conditions, and try to figure out what's wrong with these runs
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Pion/proton subtraction, normalized to pi+n p+omega peaks
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- Pion subtraction looking pretty good
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- Proton subtraction dosn't look so good
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   - somehow the proton distribution is missing the omega peak, but it 
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     does show substantial pi+n leakthrough, and also a small K+Lambda peak
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      - GH: it's essential that the pion and proton spectra used for background
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        subtraction are clean, as otherwise you will subtract K+ too
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      - No hole cut on HGC 
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         - Just <= 1.5 on HGC for proton sample, which allows pi,K near hole
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      - SK: Apply proton PID cuts, keep -5 to 5 in CT, then plot MM vs
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        CT, see where 0.8 GeV peak is popping up
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   - No Ref time cuts for pion/proton spectra
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   - also need to re-check proton CT cuts
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   - PeterB: What is the momentum here?
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      - 10.6 GeV data, SHMS ~ 6 GeV/c
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      - Pion/Proton are 0.5~ns separated in CT at 6 GeV/c
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- Meeting with Ali on HGC next week
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   - HGC is the top priority going forward
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- To Do: Want to look at BPM calibrations too
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Vijay Updates
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-------------
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Ratio of SIMC/Experimental yields
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   - 8 t bins
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   - 16 phi bins
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   - plots at high, mid, low epsilon to show the code is working
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- Experimental yields not finalized, so shouldn't expect much yet
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- Ratios generally sensible for high, mid, low and low epsilon given the lack
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  of iterations, but the phi distribution has a weird dip
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   - thinks it's a SIMC model issue
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   - DaveG: Could be an artifact of not having offsets, they aren't finalised
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     yet
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   - Peter B: is the 2.7-3 mrad Out of plane offset in?
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         - Typical offset used for coincidence experiments
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         - No, net yet
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- Need to move back to yields, experimental data will move bin to bin
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   - GH: Do not have SIMC model issues, you have experimental issues
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      - Need to finalise offsets, rate dependencies etc then can come back to
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        this
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      - the data will migrate between different phi-bins, depending on the
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        offset, so don't worry about the model or LT-sep until this is
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        finalized and applied
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Nathan Updates
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--------------
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Finished aerogel calibrations
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   - Updated slides from last week, on redmine already
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- Added new calibrations files and updated databases to git
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- GH: Will have to check Redmine, do we have an area for calibrations?
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   - If not, maybe a new area for this would be nice
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   - otherwise, your final slides on the calibration will be difficult to locate
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First look at the HMS cherenkov calibration
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   - Got the existing code going
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   - Ran for 15-20 runs or so
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- GH: Selecting pi- to do the calibration?
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   - Dave G - No, don't need pions to be high momentum, better to use delta
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     knock-on electrons as source of low PE events
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- PeterB: Use a run with a lower momentum setting for two reasons
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   1) Higher pi- to e- ratio at low P
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   2) Lack of pi- Cherenkov radiation
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      - Threshold set to 4.5 GeV/c?
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      - Dave G - Sounds about right
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- Picked a random set of runs between 12000-16000, just ran them to check what
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  they look like
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   - Will do a more systematic pass now, looking more carefully at the pi-/e-
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     ratio (see runplan spreadsheets) and the pi- Cherenkov threshold
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Junaid Updates
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--------------
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HMS DC calibrations
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   - 9.2 GeV beam energy, 2021 run
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   - Applied electron cuts (HMS Cer NPE Sum > 1.5, HMS ETotNorm > 0.7)
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     RED=before calib, BLUE=after calib
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   - Residuals mostly improved, but still get double-peaked distributions for
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     some planes
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   - changed a few parameters and still waiting on second replay
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   - DaveG: Does the code work by doing groups of 16 wires or individual wires?
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      - Not sure, will need to check.  Not sure whether groups of 8 or 16 wires
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        are used
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   - Dave G: Time window cuts are applied?
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      - Yes
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   - GH: Who has the HMS calorimeter on their list?
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      - Junaid
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         - Working on calorimeter already too, modifying batch script
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      - SK: Reminder to be a bit more selective with SHMS calorimeter
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        calibrations, only want -ve polarity runs
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Ali Updates
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-----------
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Heep Coin Analysis, offset studies
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- Richard talked about the new SIMC kinematic variable calculations in the
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  Quarterly Analysis Meeting
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   - Using these when comparing with data
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- Last week reported a constant 13 MeV shift in out of plane offset (Pmy)
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  in all kinematics
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- Juanid: What is the physical origin of the OOP offset?
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   - AU: Correspondence to difference between two reaction/scattering planes
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     compared to what we actually think
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      - HeeP reaction is inherently coplanar
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      - Physically, comes from spectrometer misalignment?
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   - Dave G: Could be something in carriage that isn't flat, not pointing
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     correctly
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   - PeterB: Mark Jones believes it's a property of the magnets, magnetic axis
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     of one spectrometer is a little bit offset
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      - changes ThetaE (xptar) and adds 0.0027 to it
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      - seems to be a property of the spectrometer, also had similar offset in
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        6 GeV era
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         - Add 2.7 mrad to -xptar (theta_e angle)
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         - Lots of ways to check it, HeeP, asymmetries
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      - TH: Yes, had two offsets in this era too
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      - DG: Look at Fig 3.11 in TH thesis
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- First look at Out of plane offset
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   - Constant 13 MeV PMy shift
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      - An angle offset works out into a momentum offset when you calculate
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        momentum quantities, as a percentage of the spectrometer central
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        momentum
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   - Tried applying offset to SHMS first, smaller range of central momenta
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   - found the angle offset needed to put PMy near zero
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   - Plotted Pmy offset vs SHMS momentum
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      - 6.2 beam: 0.0038
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      - 8.2, 10.2 beam: both are 0.0030
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      - projecting to higher P_SHMS would give significantly smaller offsets
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        for physics settings 
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   - Dave G/Tanja: How can you do this for Physics settings? Not kinematically
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     constrained?
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      - Could just use 0.003 everywhere
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   - Tanja - Can't just use an offset/make one up to fix the data
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      - These are just projections/expectations for physics offsets
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   - GH: Should get error bars for three HeeP points, based on the widths of
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     the PMy distributions, then I expect you will find a flat fit will be
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     sufficient
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   - Vijay: How can you get OOP offset without getting other offsets
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      - Garth - OOP offset is independent of the others, since Heep reaction is
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        coplanar
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         - the HeepCheck program only gives the in-plane offsets
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         - Can set/fix OOP offset, then use the HeepCheck program to get the
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           rest, OOP offset is separate
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         - Need to determine OOP first before determining the others
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            - Didn't really fully appreciate this until last week
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   - Vijay: Even after adjustment from Richard, plots still don't match
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      - Ali: Yes but this is a limitation of the data
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   - PeterB: What does Pmy correspond to?
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      - xptar
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   - PeterB: Actually looked at asymmetries of exclusive pions to determine
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     this offset, didn't really have enough HeeP runs
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      - Should take the events, calculate angle between two planes for HeeP
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        settings you have
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      - also looked at the azimuthal asymmetry of the exclusive pi+ events,
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        although this is tricky because of the interference terms
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   - PeterB: Previously found that it was more consistent to apply the offset to
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     the HMS
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      - Offset was consistent in 6 GeV era, only spectrometer in common is the
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        HMS, implies it's an HMS issue
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      - please try an HMS offset and see how well it works
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      - DaveG: Figure 3.11 in Tanja’s thesis has a nice description of how to
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        separate HMS and SHMS out of plane offsets
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   - Peter is applying offset directly to xptar
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      - GH: How do you do this?
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         - recall that PB recalculates all variables from scratch via a script
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         - xptar += 0.0027, manually reconstruct whatever is shifted
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            - Recalculate all Physics variables from xptar etc
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            - Only read in non-offset data from the replay
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      - Plot coplanarity delta
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      - Do it for all settings, see if coplanarity offset is independent of
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        momentum
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      - CYero found a slight dependence in the offset, but basically the same
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        as PB
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   - TH: it's important for everyone to be familiar with what was done in her
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     thesis, Peter and Carlos work, etc.
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      - try to learn from everyone's experience and not lose time working out
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        the procedure
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Very useful offsets discussion.  Summary to things for Ali:
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- review TH, CY theses offsets discussions
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- try an HMS OOP offset
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- try estimating errors in each OOP offset as this affects what conclusions to
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  draw when extrapolating to physics settings
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Alicia Updates
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--------------
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- Finished exams on Tuesday
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   - Hopefully something to show next meeting
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- Experimenting with HGC cuts to see if it makes any difference in BSA data
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- Getting SIMC running
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   - MM changed significantly as a function of t
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   - would like to see that pi+n peak looks like versus t
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- Hopefully some of this to show for next week
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Jacob Updates
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-------------
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- Welcome back Jacob :)
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   - will meet with Junaid and Nathan next week
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- PeterB asks about the status of optics
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   - can show some delta-optimizations next week
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Next Meeting
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------------
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- Thur May 4 @ 16:00 Eastern/14:00 Regina/13:00 Pacific
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- PionLT will go first
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