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Sep 26/25 PionLT/KaonLT Analysis Meeting Notes
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----------------------------------------------
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(Notes by GH)
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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, Nermin Sadoun, Nathan Heinrich, Alicia Postuma,
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Nacer Hamdi, Muhammad Junaid, Jing Sin Hu
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JLab - Dave Gaskell
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York - Stephen Kay
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CUA - BC Manoj, Sameer Jain, Tanja Horn, Chi Kin Tam
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FIU - Pete Markowitz
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MSU - Wenliang Li
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Virginia - Richard Trotta
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JMU - Ioana Niculescu
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CSULA - Konrad Aniol
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Alicia
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------
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- please have your comments on the BSA paper and response to referees by
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mid-next week, if possible
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u-channel initial results
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- improved MC fitting algorithm
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- using Pythia, rho, omega, eta, eta', pi0, as well as pi+, K+ leakthrough
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Q2=3, W=3.14, SHMS center
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- no t-phi binning, but a cut to exclude high -u where there are few omega
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counts
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- after subtracting backgrounds, the omega SIMC and Data have fairly good
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agreement over the 0.7<MM<1 GeV^2 region
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- divide into 8-phi bins, fits for each work reasonably well
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- BSA for all phi-bins except one are non-zero, A=-0.2 +/- 0.2, no clear
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sin(phi) shape
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- Bkd Asymmetry is essentially zero
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- this is one of the higher statistics settings, BSA analysis does not look
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very promising
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- Looked briefly at omega/eta, omega/eta' ratios
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- eta, eta' have different u-coverages, which makes forming ratios at common
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u difficult
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- maybe could do omega/eta, omega/eta' vs Q2, each one integrated over full
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u-range, so the integrated region would not be the same for different
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mesons
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- the uncertainties for this are likely high, not the best use of Alicia's
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time, but it would make a good summer student project
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- Looking at options for L/T-separation
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- compared statistics w/Bill's thesis. Looks to be a bit higher after
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diamond cut is added
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- lowest stats Q2=5.5, W=3.02 setting would be comparable to Bill's worst
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stats
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To Do:
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- run all SIMC models for all settings
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- replay low epsilon data, push code to GitHub
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Bill: the Pythia fit is really nice, it looks like you would be able to extract
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u-channel rho cross sections for the first time, since the MM distribution is
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clearly different from Pythia
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- he is also interested in seeing if this will allow rho to be extracted from
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his thesis data, since people have been asking about it
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Nacer
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-----
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KaonLT Q2=0.5 LT-sep Iteration=3
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- keeping LT,TT=0 in model but not in Rosenbluth fit
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- both L,T use the same functions, but the exp(-p*(t-tmin)) parts have
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significantly different values
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- plots of sigL,T vs t show that sigT_model doesn't have a good fit compared
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to sigT_exp
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- sigL function goes crazy at low -t<0.08
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- data/MC ratio ~1 for all t-bins except lowest one
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- some phi-oscillation for 3 highest t-bins, a bit flatter at low epsilon
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which makes sense due to the epsilon-dependence
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- trying to keep sigL exponent from exploding at low -t, setting p5 in exp term
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- ad-hoc set a plateau for -t=0.08, for -t<0.08 sigL is flat at the -t=0.08
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value
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- then Data/MC=1 for lowest t-bin, but ratios in other bins are a bit
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higher
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- after looking closely at how the ratios behave, decide to fix p5=100 in the
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sigL model
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- sigL still rises, but only to ~8 at low -t, instead of ~80
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- get Data/MC ratios ~1 for all bins, some phi-oscillations
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- asks whether it is better for him to next try a polynomial for sigL,T, or is
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it better instead to accept fixing p5 and move to LT,TT?
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- Dave: the behavior of sigL,T at low -t is suspicious, is there a slight
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shift in between the t-distributions at high,low epsilon that could cause
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this?
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- *NB* suggests to look at MM peak compared to SIMC, are these MM offsets
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much different between high, low epsilon?
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- it would also be interesting to see if there's a t-dependence to the
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offset?
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- *NB* Nacer will also recheck the pion-subtraction at low -t, as earlier
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suggested by Richard
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- Nathan: mentions the bug in Heepcheck that Gabi mentioned at the quarterly
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analysis meeting
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- *NB* Garth needs to investigate
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Richard
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-------
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Working on Q2=4.4, 5.5, will present results next week
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Junaid
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------
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PionLT Q2=3.85 changes to functional form
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- LT,TT both have a p1/(p2+|t|^2) form
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- LT goes crazy at low -t, while TT seems better behaved
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- try LT with p1/(|t|^p2) form, still sees big phi-oscillations in Exp/MC
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ratios, need to try something different for LT, happy with TT form
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- *NB* Richard: suggests to remove 1/Q^2 term in LT,TT
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- look at Fpi-2 parameteriation, LT function was complicated and TT simpler
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- *NB* Garth suggests to try TT form for LT
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- Junaid can also try Bosted LT form
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Nathan
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------
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PionLT Coin Lumi update after Quarterly analysis meeting
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- iFarm is back up, will have updated plots by end of day
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- *NB* need to double check Tracked Boiling Study, the yield calc had a bug,
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was fitting instead of integrating the plot, hoping this will result in
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better Tracked Boiling results
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- regarding the CoinTime Blocking Corr, at the Quarterly meeting Mark had
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suggested to place tighter timing cuts on individual hodoscope planes
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- *NB* planning to look at this, might need to ask Mark for a suggestion on
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how best to do this
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- the hope is that this would result in less scatter in the Normalized
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Yields used in the Coin Lumi vs Rate, used to determine the AdHoc
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correction
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- if the scatter is less, so will be the systematic uncertainty, which
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would be quite valuable since the AdHoc correction is at the moment one
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of our larger systematic uncertainties
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Chi Kin
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-------
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KaonLT Q2=3.0 W=3.14 LT-sep
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- finished iteration scripts
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- tried doing own t-phi binning as an exercise
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- Garth: it's important that the phi bins be of equal size
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- *NB* Nacer: plot high and low epsilon t-dependences on top of each other,
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so you can try to optimize the statistics between them, both epsilons
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require the same t-binning
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- finding that the Data/MC ratios are diverging after more iterations
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- some suggestions on looking at all of the intermediate plots to better
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diagnose what is going on
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- both Richard and Nacer are available for consultations
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Next Meeting
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------------
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- Fri Oct 3 @ 11:00 Eastern/9:00 Regina
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- PionLT will go first
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- as the meetings are getting quite long, and we don't want to miss important
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issues in discussions, we should discuss various options, such as maybe 2
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shorter meetings per week
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