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Global CKM Fits with the Scan Method

High Energy Physics - Experiment 2015-06-12 v4 High Energy Physics - Phenomenology

Abstract

We present results of a unitary triangle fit based on the scan method. This frequentist approach employs Gaussian uncertainties for experimental quantities, but makes no arbitrary assumptions about the distribution of theoretical errors. Instead, we perform a large number of fits, scanning over regions of plausible theory errors for each quantity, and retain those fits meeting a specific confidence level criterion, thereby constraining the ρˉηˉ\bar \rho - \bar \eta plane using the standard input measurements (CKM matrix elements, sin2β,Bd,s0\sin2 \beta, B^0_{d,s} mixing, ϵK\epsilon_K) as well as branching fraction and \CP asymmetry measurements of B decays to PP,PV,VVPP, PV, VV, and a1Pa_1 P final states to determine α\alpha, D()K()D^{(*)}K^{(*)} modes to determine γ\gamma, and D()πD^{(*)}\pi and DρD\rho modes to determine 2β+γ2\beta +\gamma. We parameterize individual decay amplitudes in terms of color-allowed tree, color-suppressed tree, penguin, singlet penguin, electroweak penguin, as well as WW-exchange and WW-annihilation amplitudes. With this parameterization, we obtain a good fit to the measured branching fractions and \CP asymmetries within the Standard Model {\it ansatz}, with no new physics contributions. This simultaneous fit allows us to determine the correlation between α\alpha and β\beta as well as between γ\gamma and β\beta.

Keywords

Cite

@article{arxiv.1301.5867,
  title  = {Global CKM Fits with the Scan Method},
  author = {Gerald Eigen and Gregory Dubois-Felsmann and David G. Hitlin and Frank C. Porter},
  journal= {arXiv preprint arXiv:1301.5867},
  year   = {2015}
}

Comments

10 pages, 8 figures, version uploaded to Phys. Rev. D

R2 v1 2026-06-21T23:14:54.271Z