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Kaon LT Meetings » mtg_25feb20.txt

Garth Huber, 02/20/2025 05:45 PM

 
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                 Feb 20/25 PionLT/KaonLT Analysis Meeting Notes
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                 ----------------------------------------------
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                                (Notes by GH)
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                     Today: PionLT will be discussed first
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Present
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-------
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Regina - Garth Huber, Alicia Postuma, Muhammad Junaid, Nathan Heinrich,
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   Vijay Kumar
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CUA - Tanja Horn
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JLab - Dave Gaskell
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Virginia - Richard Trotta
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FIU - Pete Markowitz
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Ohio - Julie Roche
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Junaid
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------
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Implications of updated HMS optics matrix elements
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- reply received from Mark re. optics offsets
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  - for P<5.5 GeV/c, use phi_offset=0 for HMS, phi_offset=-8.6E-10 for SHMS
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    - Dave: the SHMS offset is so small that you can simply use zero for it
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- GH reran the global Heep in-plane offset analysis for 9 settings
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  - beam energy offsets are a bit smaller than before (with old ME), momentum
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    and angle offsets are similar
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  - comparo Data to SIMC Heep distributions:
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    - W distributions look good
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    - various discrepancies between EM and PM components
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    - highest beam energy (10.55 GeV) is worse than the others
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  - we also note that the beam energy offset at 10.55 GeV has a strange value
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    compared to the others, the other 8 are all negative >-0.4, while the
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    highest energy setting is positive +0.4 (the max value allowed by the arc
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    energy measurement uncertainty)
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  - this setting has P_HMS=5.878 GeV/c
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  - Dave: the optics angle offsets for this momentum have been fit, but not yet
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    delta, there might be a residual saturation effect causing the different
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    behavior compared to the others
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    - suggests that GH try fitting offsets where the angle offsets are the same
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      as the other 8, but P_HMS offset is allowed to vary separately by a
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      larger amount
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    - Tanja and Julie confirm that the delta offsets are in progress, hopefully
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      will be done "soon"
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Next steps:
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- Heep Data/MC yield ratios
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Nathan
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------
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Gave some feedback following his talk at WNPPC
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- people were intrigued by the Proton Spin Crisis, but were not familiar with
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  it
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  - this was mentioned as part of the motivation for GPDs and studying the
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    applicability of hard-soft factorization
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- we need to be more proactive in motivating our work to a broad audience
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Richard
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-------
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Continued work on KaonLT L/T-separation
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- changed Wfac to 1/(W^2-M^2)**(polynomial) where W_cent is used instead of W
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  varying for every bin
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  - this made things easier, particularly the W distributions (not shown)
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- initial results shown for Q2=4.4, 5.5 with this parameterization
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  - Q2=4.4, ratios now show a t-dependence
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  - Q2=5.5, only t-bins, statistics are poor
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  - sig_L,T,LT,TT trends vs -t are similar for both settings
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    - results are very preliminary, magnitudes of cross sections don't make too
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      much sense yet, negative sigT in some places
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    - encouraged that same polynomial form can be used for both settings
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  - Garth: in particular for Q2=5.5, where data are sparse, suggests to fix the
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    non-dominant terms in the parameterization during iterations and only
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    letting the most important terms float
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Next steps:
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- will try to have sig_L,T,LT,TT results for Q2=3.0, 4.4, 5.5 using same
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  parameterization by next week
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Vijay
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-----
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Q2=0.425 PionLT analysis
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- shows diamond cut, looks good
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- tried applying Q2=0.375 model in SIMC to Q2=0.425
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  - getting negative weights, diagnosing problem
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  - a bit of a surprise, since the kinematics of the two settings are so
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    similar
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  - Garth: maybe you have hard-coded some W_cent or Q2_cent in the code that
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    needs to be updated for the new setting?
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Next steps:
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- after SIMC, will look at t-binning
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  - as was mentioned last week, will try 7 bins instead of 8
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Alicia
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------
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BSA paper modifications
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- implemented changes per referee comments
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- new title:
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  Probing Hard-Soft Factorization via BSA in exclusive pi+ electroproduction
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  from the proton
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- revisions reviewed by GH, who suggested rearrangement of material in intro
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  - the rearrangement is intended to more closely focus the intro to the new
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    title
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- proposed deadlines:
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  - circulate draft by EoB Feb 21
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  - comments due back no later than Mar 3
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  - Tanja suggests to circulate not only to this group, but to all co-authors,
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    since most comments will come from this group anyways
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    - also suggests to include Alicia's document on the referee comments at the
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      same time
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    - 2 emails to go out:
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      - all co-authors: PDF of paper and referee comments
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      - this group: OverLeaf link
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  - intending to submit to PLB by mid-March
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Next Meeting
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-------------
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- Thur Feb 27 @ 15:30 Eastern/14:30 Regina
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  - KaonLT will go first
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(600-600/600)