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Fit Region

Fit Region. [-0.1,0.2] GeV 2 are chosen Fits ending at 0.2, 0.38, 0.5 are studied. I found fit in [-0.1, 0.2] region gives the largest significance for ; because More BG appear in higher region Cannot trust MC for other  decays in higher region. Comparison (1).

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Fit Region

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  1. Fit Region • [-0.1,0.2] GeV2 are chosen • Fits ending at 0.2, 0.38, 0.5 are studied. I found fit in [-0.1, 0.2] region gives the largest significance for ; because • More BG appear in higher region • Cannot trust MC for other  decays in higher region

  2. Comparison (1) • Eff.’s and shapes from signal MC are weighed average by # tags from data.

  3. Comparison (2) Data # of candidates - sideband Sidebands from 5s Total fake Ds background is 17.0  3.1 in [-0.05, 0.2]

  4. Ds+ t+n; t+  p+n Case 2 Case 1

  5. Other Backgrounds from Ds Expected # for data in [-0.1,0.2] GeV2 Case 2 Case 1 From MC

  6. Fit Technique • Fit detail: a 2D fit • All Shapes in MM2 except fake Ds are fixed to MC, but normalizations are allowed to float • The signal shape in MDs (double Gaussian) obtained from Data when determining Ntag, and fixed • Fake Ds is described by a second order in MM2 and a first order polynomial in MDs, and the three shape parameters are allowed to float

  7. Data Fit (previous tag modes) • Fit sum of two cases •  &  dependent fit, fix N/N = Rbr  Reff =1.059  0.459 = 0.486 • Use the eff. and number of BG in the paper • Breff(Ds+  +) = (0.618  0.056)% [ (0.638  0.059)% in paper] • The 3% lower due to 3% higher in the number of tags # in 17.5 MeV MDs & [-0.1, 0.2] GeV2 MM2 region Fake Ds in [-0.05, 0.2] GeV2 is 9.5  1.9 comparing with data 9.0  2.3

  8. Data Fit (Sum two cases) •  &  dependent fit • Fix N/N = Rbr  Reff =1.059  0.455 = 0.482 • Ntag = 23286  617 • Breff (Ds  ) = (0.606  0.050)% • # of fake Ds in [-0.05, 0.2] is 19.2  2.4, consistent with 17.0  3.1 from sideband estimation # in 17.5 MeV MDs & [-0.1, 0.2] MM2 region

  9. Data Fit (case 1) •  &  dependent fit • Fix N/N = Rbr  Reff =1.059  0.243 = 0.256 • Br (Ds  ) = (0.588  0.050)% # in 17.5 MeV MDs & [-0.1, 0.2] MM2 region

  10. Data Fit (case 1) •  &  independent fit • Br (Ds  ) = (0.607  0.062)% • Br (Ds  t) = (4.9  1.9)% # in 17.5 MeV MDs & [-0.1, 0.2] MM2 region

  11. Data Fit (case 2) •  &  independent fit • Br (Ds  ) = (0.617  0.063)% • Br (Ds  t) = (6.0  1.3)% • Br (Ds  t) = (5.7  1.1)% from case 1 &2 # in 17.5 MeV MDs & [-0.1, 0.2] MM2 region

  12. Ntags My Fit KKp From CBX

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