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Kaon LT Meetings » mtg_22aug17.txt

Garth Huber, 08/19/2022 08:54 PM

 
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                Aug 17/22 PionLT/KaonLT Analysis Meeting Notes
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                ----------------------------------------------
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                           (Notes by GH and SJDK)
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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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Regina - Stephen Kay, Garth Huber, Vijay Kumar, Ali Usman, Nathan Heinrich,
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   Muhammad Junaid, Love Preet
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CUA - Richard Trotta, Tanja Horn
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JLab - Dave Gaskell
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Richard Trotta Updates
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----------------------
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- Comparing PM, EM equations between SIMC and hcana
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   - showed some derivations comparing the equations in the two codes
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   - confirmed the PM equations have a flipped minus sign in SIMC versions
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     being used for pmx etc
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   - pmy and pmz look better, pmx seems to have some tail still
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   - However, it is very important to also be sure the coordinates are not
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     rotated, in addition to the sign change
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      - SIMC x is data y
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      - Sign flip and component flip
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      - Z along beam, x points down, y is beam left (SIMC co-ordinates)
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- SIMC elastics analysis
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      - From W dist, very few inelastics
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      - From hcana, Emiss is -ve, secondary particle causing issues?
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         - shift in EM is almost certainly an offset issue, not real
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      - data EM wider than SIMC.
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         - Vijay saw it was wider than SIMC, but not by as much as Richard's
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         - Richard/Ali at higher momentum
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            - Are the "best" SHMS matrix elements being used here?
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            - Magnetic reconstruction matrix is probably the cause of the
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              broadening
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         - DG: EMiss vs SHMS delta might be a useful plot
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            - Check for unphysical correlations, e.g. that EM is not same
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              for all delta, or wiggles in correlations where they are
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              expected to be smooth
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         - Will post HeeP plots and write up on redmine
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            - Strongly looks like some magnetic optics reconstruction effect
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            - Will add EMiss/PMiss vs delta/xp/yp etc, look for wiggles and
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              correlations
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         - Will also check with Peter B if he saw anything like this in his
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           analysis of KaonLT data
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Ali Usman Updates
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-----------------
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- In switching matrix elements, Online_PionLT uses a different SHMS matrix
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  element to the one Richard/Ali are using
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   - KaonLT was using Holly's matrix elements
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   - Online_PionLT is using Mark Jones updated matrix elements
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   - Ali is replaying data with Mark Jones' matrix elements
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      - These matrix elements are expliticly labelled by MJ as the ones that
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        should be used for the 2021 PionLT data
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      - A little unclear which matrix elements are "newer" though
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      - Waiting on replays to finish
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- What about the HMS matrix elements?
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   - Some high HMS momenta in the settings Ali is looking at
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   - Haven't checked matrix elements here yet, will follow up with Jacob
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   - There are two lower momentum HMS matrix elements available, Jacob
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     recommends a certain one
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      - Compare with cdaq, see the one that is being used currently in
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        hcana.param
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- Haven't tried plotting physics data yet, just looking at HeeP
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- Richard/Ali discussed implementing efficiency script to the data
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   - When calculating normalized yields, should we apply it averaged to all fo
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     the data in a setting, or run-by-run?
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      - Yes, do it run by run
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      - In Fpi-2, we calculated an "effective beam charge"
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        Qeff=Q*effic*livetime, run by run, so the charge was scaled down,
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	rather than scaling up the observed counts
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      - also propagate the statistical and random errors run-by-run
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      - normalization systematic uncertainties should be dealt with at the end
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Vijay Kumar Updates
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-------------------
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- HeeP study for 2.7, 3.6, 3.8, 4.5 and 4.9 GeV
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   - Low energy PionLT and KaonLT settings
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   - Offsets for each energy and angle offsets for each
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   - Large momentum offset at low SHMS momentum
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      - Small offset at moderate momentum
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      - Increases again at large momentum
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      - Similar in the energy offsets too
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   - Two points with 2.583 GeV/c SHMS momentum
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      - Two different offsets at the same momentum
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      - These two points are both from KaonLT (December 2018), 3.8 GeV and 4.9
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        GeV
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      - Implies SHMS is not reproducible, which is not the case
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      - Fix certain parameters, let others vary, based upon physics knowledge
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   - Can we find some consistent set of offsets?
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      - Can't just ignore two points because they don't fit the trend
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      - Do a new offset iteration on all five settings, try and get something
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        that is globally self consistent     
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   - DG: In the past, could fit bulk of HMS settings with a single angle offset
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      - Single momentum offset until they reached higher momenta and saturation
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        effects came in
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      - no non-linearity in dipoles should exist at these momenta, don't
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        understand why the offset should be varying a low momenta
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      - i.e. the offset should depend on the physics of the spectrometer
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        (saturation) and should not be random, just to get agreement between
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	data and MC
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      - Should be able to get a consistent set, it doesn't have to be the
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        "optimal one" but rather an "acceptable and justifiable one"
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          - Vijay has an offset solution, but not the correct one yet
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   - Consider the five settings globally, not in isolation from each other
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Nathan Heinrich Updates
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-----------------------
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- Prepping for comprehensive, no report
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Muhammad Junaid Updates
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-----------------------
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- Working on runplan
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- Comprehensive prep, no report
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- Status page up to date?
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   - Stephen, working on adding the Q2 = 2.12 setting
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Next Meeting - Aug 31 @ 11:30 Eastern/09:30 Regina time
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  - GH: this will likely be the last meeting at that time, and after the run is
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    over we should reconsider the meeting schedule
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     - KaonLT/PionLT related, but at different analysis stages, should we
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       divide the meetings?  i.e. everyone is invited to both, but who gets to
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       present will be different    
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      - KaonLT meeting one week, PionLT the next?  Richard in particular thinks
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        this is a good idea
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At end, Vijay shows a New Plot
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------------------------------
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- starting to look at possible t-phi binning for the physics data
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   - One binning for pion data, different one for kaon
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   - Don't look separately at L,R,C  Add together left/center/right, see what
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     binning looks like
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- Vijay asks to have a separate meeting where GH explains in more detail how
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  the SIMC model optimization is done
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   - GH: next week would be good
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   - the way it is done in practice probably differs a bit from how its
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     explained in theses,
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