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Kaon LT Meetings » mtg_24jan25.txt

Garth Huber, 01/30/2024 02:25 PM

 
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                 Jan 25/24 PionLT/KaonLT Analysis Meeting Notes
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                 ----------------------------------------------
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                          (Notes by GH & Richard Trotta)
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                     Today: PionLT 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 - Ali Usman, Muhammad Junaid, Vijay Kumar, Nacer Hamdi, Garth Huber
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JLab - Dave Gaskell
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CSULA - Konrad Aniol
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FIU - Pete Markowitz
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CUA - Tanja Horn, Richard Trotta
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Junaid
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------
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Efficiency studies
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- CSV files of eff values created for all data
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- working on scripts for lumi, heep, and finalizing plotting scripts
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- Plotting scripts for efficiencies read in csv of efficiencies and plot from
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  there
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- updating REPORT FILES but Heep efficiencies are calculating incorrectly.  The
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  issue is the error bar of efficiencies, not the efficiencies themselves.
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  - Ali: there might be a bug in the TEMPLATE file, such as the error formula
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    somehow dividing by zero.  If efficiencies themselves are okay, then DEF
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    files ok.
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Richard
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-------
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Issues replaying Dummy runs
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- dtype error
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  - python cut script gave error for some runs and not processed
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  - fixed code to catch error when there is an empty ROOT tree.  Code now says
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    which trees are empty
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- CT cut issue
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  - met w/Stephen on Jan 24
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  - CT offset was not applied to Dummy runs.  SK missed a few Dummy runs in
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    standard.kinematics
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  - Vijay found a similar issue for some runs
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Weird features in some t-distributions
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- some (e,e'K+) runs had a spiky t-distrubtion
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  - getting events lower than the -t_min for K+ in that setting, which is a
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    sudden jump in distribution from the allowed region
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  - most likely due to insufficient PID cut, both pi+ and proton leakthrough,
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    some evidence of both pi+n and p+omega peaks
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  - after tightening HGC cut, the t-distribution looks better
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  - seems to have evidence of Lambda(1405) and other resonances in Q2=2.115
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    center, low epsilon data
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    - this is pleasant news, in the online analysis only the high epsilon data
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      (w/o diamond cut) showed strong evidence of the higher hyperon states
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- GH: suggests to generate *clean* pi+ and proton spectra, normalize them to the
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  pi+n and p+omega peaks and *subtract* them to get an even cleaner K+
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  distribution
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  - absolutely must be finalized before starting iterations!
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  - also critical to determine the correct PID efficiencies to apply to data
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Fixed binning issue
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- long-standing binning issue, some bins were always empty when binning over
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  Q2-bar, W-bar, t, epsilon
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- rewrote both binning scripts for average kinematics and yields
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- now looks much better
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Separated cross-section script
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- scripts now working!
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- now can debug things properly with average kinematics and yields
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  - some issues were encountered in not treating t-bins in a consistent
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    sequence
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- now can generate Iteration-0 plots, then can try to do the next iteration
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  - process in general works, but need to resolve PID issues first
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- DG: your high epsilon data show a weird left-right phi asymmetry that is
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  unphysical
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  - need to look more closely at what is causing this
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SIMC MM weirdness
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- plot shown for Q2=3.0, W=3.14, low-eps, center
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  - K+L MM distribution has a bizarrely long tail that is much bigger than the
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    data, exactly the opposite situation than was encountered by Alicia, where
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    the pi+n MM tail is under-predicted by SIMC
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- GH: maybe it's a radiative tail flag that is wrong??
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SIMC negative counts for some kinematics at highest Q2
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- for Q2=5.5, the Iteration-0 script gives negative weight events
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  - corresponds to sigT<0 for some kinematics
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  - the initial fit parameters in the SIMC model are completely inappropriate
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    for this Q2, and need adjustment
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  - will set to zero initially
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  - GH: if this doesn't work, then find by hand some reasonable fit parameter
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    values to try initially
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Ali
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---
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- N-Delta Transition GPDs white paper contribution for ECT* draft was sent to
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  collaborators and when feedback is returned he will send to everyone
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- Optimizing BSA code, looking at left and right settings
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  - Q2=2.115, not every bin has enough statistics
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  - If Events<Threshold cut applied, sets these bins to zero
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    - the issue is that the SIDIS+rho fits failed if not enough events
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    - GH: Bill had to do something similar in the omega analysis, as the
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      rho+PhaseSpace fits would fail if not enough statistics, or if radiation
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      corrections were too high.  This is all explained in his thesis if you
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      want
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  - weighted average of everything should cover empty bins for off-center
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    settings
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  - Made changes to weighted average scripts, should have plots for all
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    settings combined soon
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Dave
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----
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hsxpfp vs delta correction for high HMS momenta
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- looked at a subset of runs provided by Ali
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- applied correction: delta=delta+C0*hsxpfp
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  - correction factor C0<0
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- plot of C0 vs P_HMS shows a monotonic decrease to about 5 GeV/c, then
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  is reduced in magnitude from 5 to 6.5 GeV/c
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  - likely the reversal in trend is due to partial HMS saturation correction
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    applied to Matrix Elements
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- 6.59 GeV/c correlation is not totally linear, did a best fit linear
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  correction, but some slight curvature remains
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- Will provide table of numerical C0 values
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- some discussion on how to implement this in hcana
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  - if recalculate hcana values on the fly, then just recalc delta with above
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    correction, and not make any modifications to hcana
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  - Richard will implement into ltsep python framework to recalculate delta
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  - fortunately, this does not affect the PionLT data, as the effect
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    disappeared when the power supply was replaced
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- Final step will to be to optimize SIMC resolution for pi+n to get better
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  agreement between data and MC
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Vijay
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-----
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Busy with making talk for conference in India
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- EIC workshop in Bangalore
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- Will send around draft slides in next few days
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- Leaving for India on Feb 2.  Talk is Feb 9
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Nacer
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-----
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SHMS DC calibration
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- resolved all bugs for KaonLT calib w/Junaid
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- new t0 offsets needed
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- Need to compare parameterization every few runs
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  - systematically checking groups of runs.  6638-6691 shown
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- Pre-calibration X-T and new T0 (red) is usually better than post-calibration X-T
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  - this is because it over-calibrates (i.e. over-fits the wiggles in the data)
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    in particular when there are low stats
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- Basically only need to calibrate t0 and that's it. This is just tedious
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  because need to check how it varies 
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  - set up to check once per 8hr shift of data
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  - ~115 runs still to go, should be done around mid to late February
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  - batch jobs failing and such take a while
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Next Meeting
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------------
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- Thur Feb 1 @ 15:00 Eastern/14:00 Regina
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  - KaonLT will go first
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