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Kaon LT Meetings » peter_mtg_23jun25.txt

Garth Huber, 06/29/2023 03:45 PM

 
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                NOTES FROM ALI_MINI MEETING (2023-06-25)
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                         Richard L. Trotta III
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◊ Look into absolute error on target thickness
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◊ HGCer efficiency
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  ◊ Peter said I didn't need to use HGCer for kaon cut
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  ◊ SIMC HGCer cut, hgcer_eff*weight as the correction
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  ◊ SIMC aerogel tray cut
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  ◊ HGCer for two regions, in each region plot avg photo-electrons as a function of the momentum
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    ◊ Poisson distrobution was used to get the actual efficiency for given number of photo-electrons
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  ◊ For each region of the HGCer, Avg number of photo-electrons for all runs of a momentum setting. Then plot this avg vs momentum in each region.
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    ◊ Apply hole cut
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    ◊ Plot NPE of each region
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    ◊ Root can provide the avg NPE.
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    ◊ Repeat for each run of a momentum setting and get the total avg for that momentum setting
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    ◊ Modify HGCer eff script to get NPE of each region per run. Make a CSV file with momentum, avg NPE, run number. Use CSV to get avg NPE per momentum and fit with a Poisson to get the efficiency (by integrating under the curve??).
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◊ Luminosity
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  ◊ BCM correction factor: if current < 60 then bcmcorr = 1.0+0.045 * (log(60.) - log(current)) /(log(60.) - log(2.))
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  ◊ BCM correction factor: if current > 60 then bcmcorr = 1.00+0.010 * (current - 60.) / 25.
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  ◊ Apply to current as current = current * bcmcorr
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  ◊ Plot EL_CLEAN with no cuts, should be very stable
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  ◊ Peter had scalers (EL_CLEAN) within 0.1-0.2%
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  ◊ Plot production with HMS EL_CLEAN vs current for settings with a variety of currents. Study each individually (even dummy can be used) and the boiling should be obvious.
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◊ Kaon PID
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  ◊ For pi/proton peaks in MM_k, simulate in SIMC and then subtract
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  ◊ Aerogel
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    ◊ make sure geometric cuts match in data and SIMC and don't include any low efficiency regions
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    ◊ use 3 NPE cut rather than 1.5 to have less protons
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  ◊ HGCer
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    ◊ In data, require <1 NPE
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    ◊ In SIMC, remove events that have pion ID (i.e. kaon has decayed) at the aerogel position AND are outside the hgcer hole
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    ◊ The simc ntuple variables that give the particle mass squared and position in spectrometer can be used to remove these kaon decay events
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    ◊ This is an important correction, especially at low momentum. Quite a lot of kaons decay in the hut, but the decay pion makes a track and passes all the way to the aerogel and calorimeter.
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    ◊ To be even more accurate, the "weight" can be multiplied by (1-pi_eff) IF the particle is a pion and L<21 meters or so (where 21 is the aerogel L).
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    ◊ To simulate the shape vs MM of pions in SIMC, again multiply the weights by (1-pi_eff)
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    ◊ In simc, you should not only run ep->(e, n, pi+), but also the channel ep->(e, pi, Delta0). The threshold for this reaction is 1.08 GeV, and so it falls under the 1115 Lambda peak. The shape is a curve that rises very quickly above 1.08 GeV, so exclusive pions would underestimate the pion background.
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