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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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