B h h h hKpi Physics motivation

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B ? hhh- (hK/pi)Physics motivation

• Charmless hadronic decays of B meson can be used
  to
• Constrain parameters of the CKM matrix. SU(3)
  symmetry in the light-quark sector can be used to
  reduce theoretical uncertainties.
• Study hadronization dynamics
• Three body decays can proceed via multiple
  interfering channels. An amplitude analysis
  allows to determine contributing quantum
  mechanical amplitudes.
• SU(3) relations can be used to place
  model-independent constraints on Penguin
  contributions.
• Amplitude analysis can be used to determine UT
  angles a, ?.

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B ? hhh- (hK/pi)References

• Theoretical
• M. Beneke, G. Buchalla, M. Neubert and C.T.
  Sachrajda, Phys.Rev.Lett 83 (1999) 1914
• Y. Grossman, Z. Ligeti, Y. Nir, H. Quinn, Phys.
  Rev. D68 (2003) 051801
• Experimental
• BABAR quasi two-body or inclusive Phys. Rev.
  Lett. 91 (2003) 051801, hep-ex/0308065
• BELLE-CONF-0338 (amplitude analysis of B ?
  KKK-, B ? Kpp-)

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B ? hhh- (hK/pi)Datasets, final States

• Using BABAR Run 1-3 datasets (113.3 fb-1
  on-resonance, 12.1 fb-1 40 MeV below ?(4S)
  resonance).
• Using three body charmless preselection
• Final states include pipipi-, Kpipi-,
  KpiK-, KKK-, pipiK, KKpi-
• Simultaneous analysis of multiple final states
  because of K/pi misidentification
• Branching fractions are of order 10-5, no signal
  is expected in the two modes, they are used to
  control K/pi misidentification
• Kaon loose PID selector used to classify
  candidate into final states
• Candidate multiplicity per event is 1.02, random
  candidate is chosen if multiple candidates are
  present

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B ? hhh- (hK/pi)Classification
probabilities, KaonLoose
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B ? hhh- (hK/pi)Continuum background
suppression

• Three layer, four input perceptron neural
  network is used to suppress the dominant qqbar
  continuum background. The variables used are
• Cosine between candidate thrust axis and z axis
• Cosine between candidate momentum in c.m. and z
  axis
• L0, L2 Legendre moments of rest-of-event
  momentum flow w.r.t. candidate thrust axis
• Some correlation is observed between neural
  network output and Dalitz plot coordinates. Mode
  dependent cut on neural network output is applied
  to achieve qqbar background suppression

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B ? hhh- (hK/pi)Neural network output
Simulation Data
Red - signal MC, green - B-bkg, blue - sideband
Black data, blue fit
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B ? hhh- (hK/pi)mES fits
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B ? hhh- (hK/pi)Event counts
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B ? hhh- (hK/pi)Ready for amplitude fits