## Kaon LT Meetings » mtg_24apr04.txt

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Apr 4/24 PionLT/KaonLT Analysis Meeting Notes |
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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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Regina - Garth Huber, Nathan Heinrich, Nacer Hamdi, Ali Usman, Alicia Postuma, |

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Muhammad Junaid, Vijay Kumar |

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FIU - Pete Markowitz |

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Nathan |

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PionLT Lumi update |

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- still waiting on Dave Mack re BCM calib, will prompt him tomorrow |

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- have calibs that are valid for 2 lumi scans @ 9.2 GeV, show first results |

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9.2 GeV Carbon Scan #1 |

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- sees a small trend in HMS TrkEff over 0-15 kHz range, 99.8-99.75% |

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- SHMS TrkEff shows similar trend, but up to 200 kHz |

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- sees a 5% drop in RelYield at low beam current, corresponding to a 5% |

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over-estimate of beam current at 3uA, a 0.15uA offset |

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9.2 GeV Scan #2 |

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- similar trends seen |

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Some questions about corrections to the beam current in the scripts |

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- first there is an unusual logarithmic correction to the beam current |

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attributed to Peter Bosted |

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- after this, a second correction is applied |

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- both are applied to the values used in Nathan's analysis |

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- more investigation is needed to understand these |

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- would like to discuss them with Richard |

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- it would be helpful also if Vijay could check what's in his code |

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Junaid |

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PionLT Heep Coin settings |

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- list of cuts shown for both data and SIMC |

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- data are normalized for Q and TrkEff |

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- DetEff and EDTM are not yet applied |

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- BCM calibs not yet correct |

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- Data MC comparos shown for a variety of variables for all 9 Heep settings |

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- overall the shapes agree nicely |

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- rebinned plots for Heep offsets |

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- PMY will be used to determine OOP offsets |

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- Ali: notices that PMZ, EM resolution is much worse than predicted by SIMC |

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- could be due to a BPM calib error |

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- will discuss this further with Junaid |

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Ali |

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piDelta BSA study |

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- results shown for Q2=3.0, W=3.14 high statistics setting |

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- 2 t-bins, 8 phi-bins |

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- bins with very low statistics or Delta fit fails are excluded |

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- Procedure used for MM fit: |

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1) fit pi+n MC by matching integrals over 0.92-0.96 |

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- MC is narrower than data, so matching integrals results in the peak being |

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too high, which is offset by being below data in the width |

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2) fit SIDIS MC in region with minimal Delta contrib, 1.4-1.5 |

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- for bins where the data don't extend all the way to 1.5, the fit region is |

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slid slightly lower, keeping the fit region width the same |

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3) then fit piDelta MC to Bkd subtracted data |

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4) sum of MC is formed after all fitting |

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- Result of fit shown for low -t, all phi bins, L,C,R SHMS |

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- this is first time fits are shown with longer SIMC data runs |

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- resulting MC distributions are smoother, resulting in better fit overall |

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- MC consistently under-predicts 1.0-1.06 MM region |

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- possibly the SHMS collimator scattering that GH is implementing will help |

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fill in this region |

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- there is a slight over-prediction of data around 1.1 in -90 to -45 phi bin, |

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can be included in systematic |

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- Right SHMS: 4 phi bins |

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Left SHMS: only 2 phi bins, 2 bins removed due to failed fits, will show GH |

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later |

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- BSA shown vs phi, weighted average of L,R,C |

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- BSA calculated by integrating Delta MM from 1.12-1.4 GeV |

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- will do a MM cut dependence study later |

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- resulting asymmetry is very nicely sinusoidal |

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Vijay |

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Low Q2 pi+ LTsep iterations |

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- getting some weird results fitting interference terms |

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- new params from fitting process not behaving as expected |

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- going through code again to see if there is a bug |

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- if checks don't find anything, will try setting LT,TT to zero and try |

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improving from there |

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Alicia |

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pi+n BSA error analysis Part 2 |

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- first show of Q2=3, W=2.32 results |

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- BSA are similar to before delta-correction |

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- t=0.25-0.30 still has a wonky phi distribution |

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- Q2=2.1, W=2.95 |

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- first bin (-t=0.01-0.04) full fit is over-fitting, but still gives results |

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consistent with other bins |

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- Some small changes to Systematics Calc from Tuesday's discussion |

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- will not include (A-A') simple vs full fit comparison in RMS of |

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cut-dependence study |

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- (A-A') is much larger than the others, so lumping it into RMS calculation |

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would result in under-estimate of uncertainties |

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- delta(CUTS)=RMS[ (A-CN), (A-CW), (A-MN), (A-MW) ] |

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- shows table of errors for each point at one Q2, STAT, CUTS, BPOL, FIT |

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- then takes SYST as sum of CUTS, BPOL, FIT in quadrature |

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- shows LT' results vs -t for each setting, with double error bars |

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- we should be able to finalize the selection of CLAS data to compare to ours |

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for Q2-scan at fixed X_B soon |

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Nacer |

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Low Q2 KaonLT RFtime correction |

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- plot of P.gtr.th vs RFtime shows correlation, data is for 4-5 runs |

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- fits a straight line: 0.64-3.05*xptar |

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- applies this as an adhoc correction, RFcorrected |

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- plot of MM vs RFcorrected shows even better separation between K+L, K+S and |

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piDelta than before |

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- width of piDelta band is narrower than before |

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- will redo cut study using RFcorrected |

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- can clearly see some K+L events wrapped around the bottom of plot |

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- could not see these before due to wider pion background |

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- will need to place a lower limit on pion cut at ~0.1 to keep them |

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- alternately, can adjust RF offset by ~0.5ns to better center the K+L |

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events in the RF window |

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Next Meeting |

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- Thur April 11 @ 15:00 Eastern/13:00 Regina |

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- KaonLT will go first |