## Kaon LT Meetings » mtg_24feb15.txt

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Feb 15/24 PionLT/KaonLT Analysis Meeting Notes |
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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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Regina - Garth Huber, Ali Usman, Muhammad Junaid, Nathan Heinrich, |

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Alicia Postuma, Nacer Hamdi |

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JLab - Dave Gaskell |

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York - Stephen Kay |

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CUA - Casey Morean, Richard Trotta, Tanja Horn |

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FIU - Pete Markowitz |

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CSULA - Konrad Aniol |

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Richard |

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Updated Efficiencies |

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- needed to fix used HMS Cherenkov and Calorimeter Effs in Effective Charge |

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script |

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Now using: hcer eff=0.9730 unc=0.0006 |

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hcal eff=0.9961 unc=0.0005 |

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Fixed issue with Data/MC average ratios script |

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- was over-writing ratio values w/ just ones from Center Setting in |

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average_ratios.f |

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- this means Left and Right settings were not included |

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- of course this makes a big difference to the phi-coverage at higher -t |

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- a short discussion followed on the optimal number of t,phi bins to use, how |

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many is too many? |

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- the important issue is to have sufficient statistical significance to |

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distinguish a potentially small sig_L from zero |

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- From the online KaonLT statistics, GH had estimated #t-bins (K+Lambda): |

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Q2=0.50 x=0.09 5 t-bins |

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2.115 x=0.21 5 t-bins |

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3.00 x=0.25 5 t-bins |

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3.00 x=0.40 2 t-bins |

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4.40 x=0.40 2 t-bins |

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5.50 x=0.40 2 t-bins |

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This is only an approximate guide, might need fewer bins to have good |

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L/T-separation |

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- using 10 phi bins now. Seems appropriate. pi+ channel can probably use 16 |

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bins. |

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Corrections to calculation of statistical uncertainties |

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- had a long discussion w/ Ali, a second meeting with GH |

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- reviewed equations from T.Horn and W.Li theses |

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- for Q2=2.115 delta-R_bin: 5-10%, and dY_data_bin~dY_simc_bin |

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- surprised SIMC errors aren't smaller, given #evnts generated, will |

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investigate further |

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Aerogel/HGC cuts in SIMC |

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- aerogel tray cut applied in recon_hcana, while HGC cut is applied in |

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lt_analysis |

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- the HGC cut is arranged this way to be more consistent w/ data analysis |

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- comparing data & SMC x,y_HGC plots w/ hole cut |

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- sees a 10cm X-shift in HGC cut compared to Vijay |

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GH: perhaps RT and VK are projecting to different z_HGC locations? |

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Pion/proton leakage subtraction script |

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- GH: need to use pi+ data instead of simulation, since the K+L peak lies above |

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the Delta0pi+ and inclusive region, pi+n simulation would only include |

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radiative tail and none of these other contributions, would then have to run |

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multiple SIMC generators to get all of the contributions, making for a much |

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more complicated fit |

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- This is even more important for K+Sigma extraction! |

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Unseparated XSect systematic studies |

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- met with TH to discuss systematic error table |

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- nice table listed on what cuts to vary for each systematic study |

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Tracking: compare pruning and chi-square methods |

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Acceptance: vary acceptance cuts |

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PID: compare high, low epsilon HGC hole cuts |

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Kinematics: vary angle, momentum, energy offsets |

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MC Model: vary fit model parameters from final iteration values |

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Radiative Tail: SIMC w/ and w/o rad flag |

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Issues w/ generating new parameterization |

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- now that L,R,C ratios issue fixed, things starting to look good |

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- initial indications is that t-dependence in the model is wrong |

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- will try removing t-dependence to sigT |

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Ali |

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--- |

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Optimizing SIMC MM resolution |

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- high epsilon 10.6GeV data have worst resolution mismatch |

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- using data dists from most recent full pass replay, incl TOF-CT leakage |

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correction and offsets |

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- SIMC also offset corrected |

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- initial plots only for SIMC resolution tuning |

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- Dave's delta correction not included |

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- shows plots for central settings only, expect L,R to be very similar |

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- one SHMS resolution tuning parameter used for all kinematics |

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- Q2=3.0 W=2.32 HMS=6.58 - mismatch is fairly large here |

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- Q2=5.5 W=3.03 HMS=3.26 - best resolution agreement |

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- shows t-binned Q2=5.5 plots from Alicia |

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- overall, the agreement is better now |

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- definitely see a t-dependence to the discrepancy, so the t-binned plots |

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will be vital for determining a final correction |

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- added HMS DC resolution correction from Abhyuday |

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- didn't see any significant improvement for Q2=3.0 W=2.32 center |

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- DG: how much is the SHMS resolution changed by? |

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- a multiplicative factor is used in SIMC, 9x |

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- seems very high! |

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- Nacer: asks some questions about the pi+n SIMC model |

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- GH: it would be valuable to check 1-2 low epsilon settings where P_HMS is |

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lower |

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- Nacer: any final discrepancy between data and MC agreement should end up |

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being quoted as part of the Model systematic error |

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- GH agrees with this |

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Alicia |

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Recap of BSA analysis status |

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- need to implement Dave's delta-correction and troubleshoot |

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- then rerun BSA calc, mean kin, cut dependence scripts |

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- will arrange a separate future meeting to discuss error propagation |

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- then finalize Q2-scans at fixed xB including Hall B data |

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- goal of distributing draft paper by end of March |

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Troubleshooting delta-correction |

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- delta_corr=hsdelta+6.0*hsxpfp |

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- Problem: finding that MM resolution w/o correction is worse than from hcana |

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- DG: to do a quick check, used an old script which calculated MM like old |

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6GeV ENGINE |

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- should use Richard's recon script instead, which has same MM formulas as |

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hcana |

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- the issue is that hcana has improved corrections for xtar dependence |

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compared to ENGINE, since longer target lenghts are used in 12GeV running |

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compared to 6GeV |

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- sees an improvement when the delta-correction is applied, but will need to |

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redo the study due to different MM calc than hcana |

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- Ali will also have to retune SHMS resolution study after Alicia is done her |

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study |

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- Alicia's t-binning plots at Q2=4.4 shows that Ali's 9x resolution factor is |

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too big |

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- would like SIMC to never be wider than data, for any t-bin |

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Nacer |

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DC calibs |

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- pushed changes to GitHub |

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- Junaid should check things over before accepting |

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- maybe Ali can look things over as well, as he's more familiar with KaonLT |

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layout |

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- hoping to submit full replay over weekend |

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Nathan |

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- catching up on things after being RC |

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- BCM param map now set up |

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- hoping to have some Lumi plots next week |

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- will start with the robust singles study from end of PionLT run |

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Junaid |

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Tracking Eff study |

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- plots of EDTM, Elec_sing_TrkEff, Elec_COIN_TrkEff, Hodo3/4Eff for HMS |

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- a small number of outlier runs (eff=0) that need checking, but overall |

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looks good, with reasonably tight, monotonic trends vs rate |

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- similar plots for SHMS |

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- also a few outliers that need checking |

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- pTRIG6 runs for HMS also shown |

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- these were for the ELREAL trigger efficiency study |

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- HeepCoin data plots |

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- plot of SHMS >1MHz Hodo rate shows sharper drop off of eff at very high |

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rate |

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Next Meeting |

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- Thur Feb 22 @ 15:00 Eastern/14:00 Regina |

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- PionLT will go first |

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