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Kaon LT Meetings » mtg_23feb09.txt

Garth Huber, 02/10/2023 04:29 PM

 
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                 Feb 9/23 PionLT/KaonLT Analysis Meeting Notes
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                 ---------------------------------------------
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                           (Notes by GH and SJDK)
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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 - Stephen Kay, Ali Usman, Alicia Postuma, Nathan Heinrich, Garth Huber,
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   Vijay Kumar, Muhammad Junaid, Love Preet
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JLab - Dave Gaskell
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CSULA - Konrad Aniol
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CUA - Tanja Horn, Richard Trotta
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Nathan Updates
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--------------
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Result of detector time and reference time cut analysis
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- Q2 = 3.85, W = 2.62, Left, Low eps (LH2+), whole setting
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   - With new cuts, fine ~200 more pions compared to online
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   - ~2.5% more events (8261 vs 8070)
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   - Distributons look slightly better, very subtle changes
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- DG - Probably worth checking a setting with a poor real/random ratio
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   - May see a more dramatic difference
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   - Try a pi- run
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   - Nathan has it, but no online plots for comparison
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      - Q2 = 3.85, W= 2.62, low eps, left
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      - https://logbooks.jlab.org/files/2022/09/4039344/Q3p85W2p62left_lowe_LD-_Pion_Analysis_Distributions.pdf
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      - 4806 pions
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      - Looks like we have less now
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         - Could be that some runs were missed (setting was split in two)
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         - Please do a more thorough comparison for a pi- run
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         - REMEMBER: All data are guilty until proven innocent!
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- Pushed changes to param files, std.kin
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   - not everything is replayed yet
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   - ref time cuts stable so this part should be okay now
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   - Next step is Cherenkov calibs
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Junaid Updates
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--------------
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Back from Pakistan
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- Trying to catch up on classes/get back on track with analysis
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- DC and calorimeter calibration is next step
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Richard Updates
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---------------
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Changes to PM/EM calcs in SIMC
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- For SIMC/hcana comparison, complicated doing it in SIMC
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- Use a script to convert root file
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   - Made this and ran it
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   - Nothing looks different?
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   - New variables look the same as the old ones
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      - DG - Seems very strange
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      - RT will meet with DG tomorrow about this
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Weird Right setting from last week
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- tightened up CoinTime cuts
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- CT peaks slightly offset, will correct for at some point
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- Dramatically imrpoved MM distributions
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- Black is right, green centre, red left
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   - Black looks much improved
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   - Still a bit high, but now only by ~50% instead of 10x
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   - -t distribution no longer going through 0
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      - SK - Thought, we never plot 2D t vs anything other than phi
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      - Could be interesting to check and remove junk events
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      - t vs CT/RF?
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- For black (right) CT dist, tails are being removed - real events removed
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   - GH - Do we need to correct for this? Cutting real events?
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   - DG - Is this a final cut or just a diagnostic?
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      - In principle, spectra should look the same with tight cut or with
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        random subtraction, not the same indicates a problem that needs to
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        be investigated
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        e.g. if peaks left/right of real peak are actual physics events from
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        other process
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- Still need to optimize PID cuts
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   - only temporary cuts
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   - will have to investigate where e-pi, e-p coins are compared to e-K and
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     adjust cuts accordingly
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- Maybe cuts not being applied correctly for right setting?
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   - Something is clearly dramatically different for the right setting
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   - GH: Right setting probably has high SHMS rates, at very forward angle
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     Please *look up* running conditions of right setting comp to cent, left
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Ali Updates
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-----------
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HMS Cherenkov and calorimeter efficiency study
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- slide nicely lists ALL cuts applied
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- Wide range of kinematics investigated in KaonLT data
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- Run 4871: 
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   - Cherenkov efficiency is very low (94.82%)
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   - Cal eff=98.66%
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- Run 4919:
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   - Cher eff=93.96%
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   -  Calorimeter efficiency v.low (90.75%)
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   - A lot of pi- contamination present, not a good setting for efficiency study
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- Run 4987:
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   - Cherenkov efficiency ~97.15%
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   - Cal 98.93% - Calorimeter a little low?
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- Run 5222:
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   - Cherenkov 96.16%, calorimeter 99.18%
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   - DG: this looks like a classic case of FADC-DT effect due to HMS-Cer light
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     leak
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     This is a *real effect* that will have to be included in efficiency
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     The complication is that this FADC-DT is in priciple rate dependent and it
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     may be tricky to separate out the rate dependence from other inefficient
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     effects
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   - Looks like we have a light leak in the Autumn 2018 data
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   - Could've been introduced when the HMS mirror was fixed
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   - Will be there for *all* KaonLT data and Summer 2019 PionLT data, so Vijay
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     needs to be careful about this in low Q2 analysis as well
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Spring 2019 data efficiencies
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- Run 7909:
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   - 75.71% Cherenkov efficiency, 96.98% calorimeter efficiency
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   - Low total efficiency in low epsilon data - it's all the pions!
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- Run 7979:
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   - Cer 94.92%, cal 99.09%
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   - Calorimeter efficiency is pretty good
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   - DG: I would expect a cal eff closer to 99.5%
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   - AU: will try applying a neutron MM cut to further clean the sample,
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     expecting a further increase of 0.5%, i.e. closer to what DG expects
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- Run 8255:
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   - Cer 71.66%, Cal 95.58%
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   - low stats in a single run, this is high Q2 low epsilon
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   - need to add more runs to get better #events
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- DG - Suggest to Look at HeeP singles to get a handle on these efficiencies
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   - Cut tightly on W2 dist, eliminate pions
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      - Should have a nice clean sample
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   - GH - Hopefully singles fill more of the focal plane than HeepCoin
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   - Most of the physics settings it's hard to get a usable efficiency number
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     due to pi- contamination in HMS
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   - GH - Focus on 1-2 settings that look promising, otherwise, focus on the HeeP
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      - Don't do a run by run efficiency, just use result from HeeP to guide this
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Vijay Updates
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-------------
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Analysing Summer 2019 Q2=0.38 data with 3 epsilon settings
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   - fixed issue with cut file, weird random peak to left of prompt peak is gone
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   - Can probably take a lot more peaks on each side of the prompt peak for
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     random subtraction
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      - At least 2 more on each side
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- Diamond cut implemented, needs some small adjustment on top edge in
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  comparison to low epsilon data
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- Still finalising t-binning
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   - ~ 45k events per bin (summed over all SHMS angles and epsilon)
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   - 8 t bins
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   - GH for first t bin, should move left edge of the bin closer to the data
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      - For low Q2 FF test, the dependence at low -t is crucial
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      - Should go very narrow on binning at low -t
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     - Could go up to 10 bins
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   - DG - What is the -t resolution?
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      - Can't bin finer than this or t0bin migration will be a big issue
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      - GH will discuss with VK how to get this info from SIMC
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Alicia Updates
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--------------
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- Assignments/presentation updates
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- No new updates, will have something after WNPPC
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Next Meeting
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------------
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Thur Feb 16 @ 17:00 Eastern/16:00 Regina/15:00 Mtn/14:00 Pacific
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- KaonLT will go first
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- SK, NH, GH, AP, LP will connect from our hotel room in Banff
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- GH, AP, LP might be a bit late
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