Mauro-Silvia comparisonMauro Raggi 26/04/2006 Analysis meeting

Last meeting results

Recent 2 parameter fit SilviaSilvia fracDE=1.3190.096Mauro Phd fracDE=1.320.076

List of selection cutsLKr energy > 10 GeVN tracks = 1. quality>0.7Pp+ > 10 GeVE su P < 0.85Muon veto hits = 00 MeV < T*p+ < 80 MeVFiducial regions cutN clusters > 3 o 4Ng =3 (in time clusters >35 cm track)g minimum energy > 3 GeVMin ene. radiated g>3 GeVCOG < 2 cm|ZVNEU-ZVCHA| < 400 cmOnly one |ZVNEU ZVCHA |< 400 cm|MK-MKPDG|< 10 MeV54 GeV 10 cm)

Acceptance cutsLKR radius track:15 110 cmDCH1 & DCH4 radius:12 150 cm DDEADCELLS:2 cm MUV Radius:12.5-135 cm Min. dist. Track-g:35 cm * Min. dist. g-cluster:10 cm

Reconstruction approachCalculate Mp0 imposing charged vertex Z for each gamma pairSelects the correct gamma coupling selecting the best p0 mass Impose Mp0 to each gamma pair to get 3 values of the neutral vertex ZVCalculate the MK for each ZV(i)Selects the pair with the best Kaon massMauroSilviaLKr > 9 GeVTime window for tracks 116-154 nsTime window for clusters 100-154 nsMore than 1 track (not used for comparison)Non common cuts

Corrections

CorrectionDataMonte-carloa & bXXNon linearities (flag 2)XLKr projectivityXBlue field XXLKr smearOFFLKr clusters shiftOFFOFF

Bad bursts and bad NT-PK runs21K ev

Bad bursts rejectedBad NT-PK runs rejectedSBUR_BADB_DCHRuns: 15652-15663SBUR_BADB_NUTRuns: 15688-15732SBUR_BADB_MBXRuns: 15733-15753 ???SBUR_BADB_HODCSBUR_BADB_LKRSBUR_BADB_MUVSBUR_BADB_PMBSBUR_BADB_PHYS ???

Data comparison

June 2005 comparison results

Starting pointOn the run 15778 from SS3 we got the following result: After a brief agreement on the values of some cuts the comparison has been started in the region of 0 < T*p< 80 MeV.Using a dedicated ppg split produced by Silvia we can now run on all SS123 data in less than 3 hours!!

Main differences discovered Different acceptance approach to gammas and tracks clusters Different kind of correction applied (missing non linearyties in Mauro analysis) LKr smear ON in Mauro analysis (difference in MC only) LKr cluster position shifts in Silvia acceptance (removed) Missing cut on track time in Mauro analysis Bug on the overlapping gammas cut in Mauro analysis

Final comparison result data 0-80Residual differencesThe main difference is due to edge effects in the T*p cut (10/33 - 21/44) - Difference in the T*p resolution to be checkedDifference on the mistagging cut (probably due to difference in ZV_cha res. )

T*p for different eventsT*pT*p

Final comparison result data 55-80The increasing difference in the sample 55

MC comparison

MC comparison: run 15778 K+SilviaTot: 13550MauroTot: 1363213222410 3.1%328 2.5%No further tuning performed so far Differences mainly due to T*p cut0

T*p for different events MCAll the discrepancy are near the edge of the T*p cut

W for different events MC

Mauro Silvia MC(IB)resolutions comparisons

Resolution comparisons T*pThe difference in resolution may explain the difference in number of events

Resolution comparisons W

Resolution comparisons Eg

Resolution comparisons PK

Resolution comparisons MK

MK data resolution MauroMauro MK(res)DAT= 2.575 MeVMauro MK(res)MC = 2.648 MeV Difference(Data-MC) = -0.073 Difference(Data-MC)% = 3%IF the same resolution difference is there also in W it may generate a fake positive interference275KeV shift of the measured MK with respect to PDG

Resolution comparisons ZVneu

Resolution comparisons ZVcha

Conclusion on resolutionsResolution difference in T*p to be understoodTry to compare pion momentumMay be due to the difference in the Lorentz tranformationWe have also a shift in the reconstructed MK that is not yet understood

SilviaMaurodiffDiff %T*p9,023E-046,868E-042,16E-0423,88W4,605E-034,602E-033,00E-060,065Eg0,12920,12866,00E-040,464PK0,37090,372-1,10E-03-0,297MK2,650E-032,648E-032,00E-060,075ZVNEU82,4282,393,00E-020,036ZVCHA81,9782,24-2,70E-01-0,329

SS123 data comparisonSilviaTot: 218811MauroTot: 220034Difference1223 events 0.55%

ConclusionsA general good agreement in term of number of events has been reaced both in data and MC in run 15778Also in all SS123 the agreement remains very goodMauro and Silvia MC resolutions are quite similar for most variables (more statistic needed to spot problems at the % level)A comparison of the MK resolution in data is mandatory Detailed study of the T*p distribution is still needed to understand the reason of the discrepancy induced by this cutMauro-Silvia comparison of data distributions has to be performed (may be different due to corrections in data only)Fit results comparison with the new selection not yet completed