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Kaon LT Meetings » mtg_24feb08.txt

Garth Huber, 02/08/2024 05:31 PM

 
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                 Feb 8/24 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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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, Ali Usman, Muhammad Junaid, Nacer Hamdi
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CSULA - Konrad Aniol
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York - Stephen Kay
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JLab - Dave Gaskell
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CUA - Richard Trotta, Tanja Horn
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Junaid
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------
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Errors on Tracking Efficiencies for Heep singles data
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- found the error in the calculation
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- data is replayed, will be looking at the results soon
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Richard
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-------
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SIMC Weights
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- last week's issue was due to weight not being applied to SIMC yields
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- with this fixed, the 10^6 factor is no longer needed
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- now getting Data/MC ratios of 0.2-0.5
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SIMC Missing Mass
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- last week reported a very long K+Lambda radiative tail, the opposite that was
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  found for the pi+ analysis
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- Dave looked at RT's input files, and found that the wrong K+ decay length was
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  used
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  - 780.4cm was used instead of 371.2cm (i.e. pi+ value instead of K+ value)
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  - SIMC would have generated the correct K+ decay products, but with the wrong
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    probablity
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  - the fact that the user has to input the correct decay length (instead of it
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    being selected automatically since SIMC already knows it's handling K+
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    decay) is a historic artifact from Dave Koltenuk days
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- a second issue was that MM was not recalculated for SIMC events by the
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  recon_hcana_script
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- with these corrected, the K+ radiative tail agrees better with the data, of
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  course the data are still subject to change as well, until the PID cut study
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  is completed
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K+ PID Studies
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- investigating pi+ and proton leakthrough into K+ sample
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- selected three different MM regions:
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  MM<1.05 (should be mostly leakthrough protons)
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  MM>1.16 (will contain leakthrough pi+ as well as real K+)
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  K+Lambda region is 1.06<MM<1.16
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- for MM<1.05 region, look at Aerogel NPE distribution
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  - saw some evidence of proton leakthrough
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  - tightened cut
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    before: events with >3NPE accepted
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    now:  events with >4.5NPE accepted
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  - still need to adjust HGC hole cut
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    - HGC optics were adjusted between low and high epsilon runs, need larger
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      hole cut for 10.6 GeV data
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- MM>1.16 region, again look at Aerogel
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  - will try 4.5NPE cut, maybe need 4NPE if cut is too restrictive
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  - need to apply same Aerogel cut to all MM regions
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Data/MC Yield Comparisons
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- looking at Q2=2.115 yields with different MM cuts
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- ratios are closer to 1 with 1.06<MM<1.16 cut applied
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Separated Xsect Comparisons
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- iteration scripts seem to work
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- some discussion of what units used for cross-sections in SIMC, Richard still
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  doing final checks
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Next Steps
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- finish PID studies
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- finish cut analysis
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Ali
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---
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Compare pi+n MM dists of Data and SIMC with Dave's delta fix
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- Bad News: somehow the Data MM distributions before and after delta fix are
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  identical, which is suspicious.  Will discuss w/Alicia after she's back
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  - Plots for Q2=5 are shown, others behave the same way
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- Good News: adjusted Drift Chamber resolution parameter in SIMC
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  - with the adjustment, the pi+MM peak agreement between Data and SIMC is
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    significantly better
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  - only adjusted the SHMS resolution so far, since it's higher rate
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  - HMS routine already had some resolution tuning (apparently from Doug
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    Koltenuk), while SHMS lacks this code
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- Dave: Abideh will look at HMS inclusive data and tweak HMS resolution there.
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  He can provide his HMS parameters when he's done, so the effects of the two
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  spectrometers can be separated that way
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- Dave: the DC intrinsic resolution should not be strongly rate dependent.
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  However, at higher rates, the Gaussian tail fraction does increase.
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  - Koltenuk's HMS resolution tuning is along this idea, with a double Gaussian
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    distribution giving bigger tails
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- Dave: when comparing SIMC to Data MM distribution, try to confine your study
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  to the region just around the pi+ peak, to avoid attributing DC resolution
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  issues to what might be problems in the treatment of the radiative tail
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  - suggest to look at +/-2 sigma region around pi+ peak, so MM<0.98
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  - really hoping the SHMS DC resolution parameter does not turn out to be
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  kinematics dependent.  If so, this would indicate that other parts of the
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  simulation (such as multiple scattering) are incomplete
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Nacer
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-----
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KaonLT low Q2 DC calibs 95% done
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- submitted last jobs this morning
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Next Steps
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- will need to replay all data with new DC calibs, and offsets
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- then can start looking at K+ PID
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  - Note: Aerogel index (n) will be higher than in Richard's data
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Stephen
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-------
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Notes that starting a new WorkFlow on SWIF seems to give a better success rate
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on iFarm jobs
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- Nacer notices the same effect
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Next Meeting
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------------
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- Thur Feb 15 @ 15:00 Eastern/14:00 Regina
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  - KaonLT will go first
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