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Kaon LT Meetings » mtg_22dec07.txt

Garth Huber, 12/07/2022 11:56 AM

 
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                 Dec 7/22 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 - Garth Huber, Stephen Kay, Ali Usman, Alicia Postuma, Nathan Heinrich
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CSULA - Konrad Aniol, Erika Gwin
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CUA - Richard Trotta
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JLab - Dave Gaskell
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Ohio - Julie Roche, Jacob Murphy
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FIU - Pete Markowitz
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Richard Updates
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---------------
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- LT separation code
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   - it's slow getting information back from Bill
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- Heep analysis
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   - SIMC/hcana calculate variables differently
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   - Adding new variables that calculate it in the same way as hcana into SIMC
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   - DG - In complete recon event or a new subroutine?
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      - In a new one
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      - DG - Should be fine
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         - Maybe call it "recon_hcana"?
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         - Don't do it as a separate branch!
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            - Will be annoying to integrate, also everyone will want this
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         - New submodule is good, will be modular then
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- Total Efficiencies per run for each setting
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   - Needed input into Bill's LT-sep code
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      - Haven't incorporated Ali's updated efficiencies
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         - Error bars are off as a consequence
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         - Some are grabbing the wrong calculations too
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   - -t binning plots/demonstrations shown for Runs 4965-5009 Left-Cent-Right
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      - ~2% downtrend seen in Effs for Right setting, probably following real
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        changes in running conditions
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      - Actual t-binning and diamond cuts will be done in Bill's LT-sep code
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      - Need to use Jacob's code to apply diamond cuts
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   - GH - For MMK plot, should zoom in on Lambda peak and see if it's
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     stable versus run number. Apply finer binning too
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      - RT - Will add it, will do 2D phi dist too
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   - GH - also need to add a slide of what Effs and typical values are used in
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     the TotEff calc, so we can see exactly what was done
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   - *Need to do a HMS calorimeter efficiency study*, can't rely on what
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     the report file gives
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      - DG: this needs to be for all PID detectors
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      - need to select some runs which are sufficiently clean and then apply
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        the obtained values globally, preferably vs. spectrometer momentum
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	 - often, can never get rid of enough pi- (for HMS), so might even
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           have to resport to Heep data, but then have to worry about not
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           illuminating the full focal plane
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      - the studies are simple, but this needs to be completed before starting
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        LT-separations
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- iFarm issues
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   - Tape silo had a robotics failure yesterday, can't get stuff from the tape
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     silo currently
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   - can only replay data already cached to disk
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Ali Updates
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-----------
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- Updates to Error Calculations
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   - Heep coin data from 6.2/8.2/10.6 GeV
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   - Error bars were too big
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   - New calculation using binomial errors
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   - need to *add* a slide showing old and new calculations
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   - New calculation shrinks error bars quite drastically
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   - For 8.2 Gev, maybe even too small
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   - 10.6 GeV looks good with one outlier
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      - All efficiencies seem to be lower for this point
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      - Has lowest beam on time?
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- DG - Need to *correct* EDTM LT for time the beam is off
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   - the issue is that the EDTM keeps counting when beam off, need to
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     correct the scalers via an approximate formula derived by PBosted
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   - Richard's Lumi script should do this?
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   - DG - *Current off correction* from PBosted study:
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      - LiveTime=(Rmeas-(1-f))/f
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      - Rmeas = edtm_accepted/edtm(nominal edtm live time)
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      - f = current(no cut)/current(with threshold)
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      - this formula is an *approximation*, assumes the beam ramp up time is
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        negligible, which may or may not be true, depending on the running
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        conditions, probably this approximation will be worse for early 10.6
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        GeV running
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    - AU - probably tnis is NOT implemented yet for Heep, physics settings,
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      will discuss with RT
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- Delta-Pi
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   - Ali has received an invitation from Stefan Diehl to present some Delta-Pi
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     results at a conference at ECT* in Trento in August
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   - will discuss JLab conference travel funds application with RT 
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Stephen Updates
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---------------
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- No new progress on RF class
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   - Will update hcana in group directory to use new RFtime variables
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   - Stephen will try to do this today, let him know if there are any issues
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     with the new hcana version, should only affect the CT/RF classes
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   - Should not need a DEF file change
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      - RFTime.* is in there currently, this will pick up new variables
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Alicia Updates
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--------------
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- BSA analysis
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   - Edited report files to calculate effs separately for each helicity
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   - Can't separate charge by helicity
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      - Will cut charge in half to normalise dummy subtraction
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   - DG - Should contact Steve Wood wrt to helicity scalers
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      - Might've been added for A1n/d2n?
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      - SK - Would explain why helicity scalers didn't work for KaonLT but were
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        added later (but still had issues)
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      - AP Should CC Carlos Yero when asking Steve on this
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   - shown runs have same TotEffs for +,- helicity to 3rd decimal point
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     but LH2, Dummy do have a different Effs
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      - DG - HGC pion efficiencies are way too low
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      - Just set them to 1 until RT/AU complete their study
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   - Weighted average of BSA for Left-Cent-Right
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   - Experimented w/Complete fit (A=sin-phi,B=cos-phi,C=cos-2phi) and
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     Approximated fit (A=sin-phi only)
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      - complete fit is over-fitting the data, ending up with B,C>A for some
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        fits
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      - DG - can constrain B,C based on world data
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         - we have LT,TT from Fpi-2 but only up to Q2=2.45
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	 - also have CLAS data
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      - SK - Glancing back at old code from his PhD analysis @ Mainz:
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       he ran an *initial fit* with just one Sin/Cos term (dashed red for
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       Alicia), and then fed this into the second fit
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         - Can adjust the second fit in a few ways then, can constraint the
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           asymmetry A to vary in some range, such as permitting A to only vary
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           within 1-2sigma of initial fit
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         - B/C can also be restricted too
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      - Julie discusses some of the difficulties of interpreting the results
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        that were used when presenting DVCS BSA data
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         - Suppressing B,C terms can make things look "more precise", but
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           actually shrinks the error bars in an unrealistic manner
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	 - in the end, the DVCS paper presented both sets of results in a paper
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           and gave a caution that the result and obtained error bar depends on
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           how the analysis is done
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         - GH - Could quote weighted everage of complete/approx fits?
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   - DG - What about *radiative corrections* to the BSA?  This is an issue that
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     just occurred to me now
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   - GH - Unlike the LT-sep results, we aren't quoting a cross section. Not
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     using SIMC to get asymmetry, while we use SIMC in the ratio method to
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     get the cross sections
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      - DG - Yes, Acceptances should cancel in the BSA
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   - GH - From SIMC studies for LT data, can *estimate* how large radiative
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     corrections are for a t bin by turning on/off the rad-corr in SIMC and and
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     how large the effect is, no easy way to see how this corrects the
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     asymmetry
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   - DG - Iterative fit? Put SSA into SIMC and see how it changes things when
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     RadCorr On/OFF
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        - maybe can also use SIMC to do t-bin centering for BSA, just like we
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          do for the cross sections via the Ratio Method
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   - DG - Interesting question, could be an advantage over CLAS analysis in
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     that we can actually study and estimate the RadCorr effects.  Will think
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     about this further
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Next Meeting
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------------
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Wed Dec 14 @ 9:00 Eastern/8:00 Regina/6:00 Pacific
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- PionLT will go first
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