Decay Electron Reconstruction Results and Other Studies For the - PowerPoint PPT Presentation

Decay Electron Reconstruction Results and Other Studies For the E-Scale Working Group Joshua Albert March 9/10, 2009

µ+ vs. µ- in MC • Used data in CONVVECT bank to see what parent and decay particles were in MC. • (-/+)11 = e +/- • (-/+)13 = µ +/- • 22 = photon • 0 = failure • The following totals are for all MC events...

µ+ vs. µ- in MC MC Count Decay Type n % µ+ → e+ 15730912 56.9% µ- → e- 9438713 34.2% µ- →γ 1458591 5.3% failure 1004858 3.6% Total: 100.0% 27633184 • (µ+ → e+)/(µ- → e-) = 1.667 • (µ+ → e+)/(µ- → e- & µ- →γ ) = 1.44 • (µ+ → e+)/(µ- → e- & µ- →γ && failure) = 1.32

Data vs. MC with apnmue/apmuetype cut data apmuetype(1) For run numbers: 621XX No Cuts apnmue 0 failure 2 gate 3 byebye Total 0 33861 40.9% 15926 19.2% 0 0.0% 49787 60.1% 1 0 0.0% 30163 36.4% 2135 2.6% 32298 39.0% 2 0 0.0% 619 0.75% 59 0.07% 678 0.82% 3 0 0.0% 14 0.02% 0 0.00% 14 0.02% Total: 33861 40.9% 46722 56.4% 2194 2.7% 82777 100.0% MC apmuetype(1) For run numbers: 621XX No Cuts apnmue 0 failure 2 gate 3 byebye Total 0 49290 59.5% 8719 10.5% 0 0.0% 58009 66.1% 1 0 0.0% 27913 33.7% 1490 1.8% 29403 33.5% 2 0 0.0% 291 0.35% 51 0.06% 342 0.4% 3 0 0.0% 0 0.00% 0 0.00% 0 0.0% Total: 49290 59.5% 36923 44.6% 1541 1.9% 87754 100.0% 39.0%/33.5% = 1.16 There may be a bug in my pulling values out, since there does not appear to be a correlation between #data & #MC events for a given run, which was previously confirmed. I will investigate tonight.

Sample Makeup • The sample used for this is made up of data and MC events for SK-IV which are identified as stopping muons. Then apply: • pass stmufit goodness (bgood != -1) • one probable decay electron found • decay electron type = gate • only use runs where both the data and MC run correctly • Plots have: 40695 MC events 48890 Data events

Selection Cuts • The following cuts were used, attempting to duplicate Ishihara-san’s cuts: • 2µs<t<8µs • n50 (# hits in 50 µs time window)>60 • egood (e recon goodness)>0.5 • Electron reconstructed vertex in FV

Plots to Check Validity • I have changed color schemes to match Mine-san. • Red = Data • Blue = MC • Green = MC truth information • The e+ vs. e- plot is the exception.

decay e vertex x 1200 1000 800 Data 600 400 MC 200 True 0 − 1500 − 1000 − 500 0 500 1000 1500 x (cm) decay e vertex y 1200 1000 800 600 400 200 0 − 1500 − 1000 − 500 0 500 1000 1500 y (cm) decay e vertex z 1000 800 600 Not good agreement 400 200 0 − 1500 − 1000 − 500 0 500 1000 1500 z (cm)

electron vertex recon distance 3500 3000 2500 True vector position - 2000 reconstructed MC 1500 position 1000 500 0 0 50 100 150 200 250 dist (cm)

decay e direction x 800 700 600 500 Data 400 300 MC 200 100 True 0 − 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1 x (cm) decay e direction y 800 700 600 500 400 300 200 100 0 − 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1 y (cm) decay e direction z 800 700 600 500 400 300 200 100 0 − 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1 z (cm)

Time to decay Data MC True 3 10 Decay Time Fits: MC True: 2.068µs MC Recon: 2.071µs Data: 2.063µs 2 10 0 1 2 3 4 5 6 7 8 9 10 t ( s) µ

Time to decay Electron 3 10 Positron Decay Time Fits: Positron: 2.203µs 2 10 Electron: 1.832µs 0 1 2 3 4 5 6 7 8 9 10 t ( s) µ

n50 Data peaks at 1800 lower n50 1600 1400 Data 1200 MC 1000 800 600 400 200 0 0 50 100 150 200 250 300 350 400 n

Number of hits in 50 µs time window n50 (2 − 4 µ s) 1200 1000 2-4 µs 800 600 400 Data 200 0 MC 0 50 100 150 200 250 300 350 400 n n50 (4 − 6 µ s) 450 400 350 4-6 µs 300 250 200 150 100 50 0 0 50 100 150 200 250 300 350 400 n n50 (6 − 8 s) µ 200 180 160 140 6-8 µs 120 100 80 60 40 20 0 0 50 100 150 200 250 300 350 400 n

Recon − True Decay Time 1000 May be two 800 peaks: 0 ns and -100ns ? 600 400 200 0 − 0.5 − 0.4 − 0.3 − 0.2 − 0.1 0 0.1 0.2 0.3 0.4 0.5 t ( s) µ

Reconstructed Momentum of Decay Electron 2500 Mean amome: Data True:38.175 MeV 2000 MC MC: 38.804 MeV True Data: 38.841 MeV 1500 1000 500 0 0 10 20 30 40 50 60 70 Momentum (MeV/c)

Reconstructed Momentum of Electron (2 − 4 µ s) 1200 1000 2-4 µs 800 600 Electron Momentum 400 200 Data 0 0 10 20 30 40 50 60 70 Momentum (MeV/c) MC Reconstructed Momentum of Electron (4 − 6 s) µ 500 400 4-6 µs 300 200 100 0 0 10 20 30 40 50 60 70 Momentum (MeV/c) Reconstructed Momentum of Electron (6 − 8 s) µ 200 180 160 140 6-8 µs 120 100 80 60 40 20 0 0 10 20 30 40 50 60 70 Momentum (MeV/c)

Quantitative results • Mean reconstructed e-momentum and hits in 50µs time window as a function of decay time: 2-4µs 4-6µs 6-8µs amome MC 38.8 MeV 38.7 MeV 38.9 MeV amome data 38.9 MeV 38.7 MeV 38.8 MeV n50 MC 224.0 224.4 225.2 n50 data 219.7 219.7 220.2

Conclusions • Amome mean for Data/MC is accurate to 0.1%, but the fit seems a bit off. • Reason why z-distribution isn’t accurate is not known • Decay time does not seem to appreciably affect other parameters • Data and MC have different numbers of decay electron candidates, something may be wrong with my analysis