Isospin constraints from/on $B \to \pi\pi$

Abstract

The Standard Model constraints on α which can be derived from the B → ππ decays are revisited in some depth. As experimental inputs, the B 0 → π + π − , B + → π + π 0 decays complemented by the B 0 → π 0 π 0 decays, the CP parameters S ππ and C ππ , and/or the value of α as determined by the global CKM fit are used. The constraints discussed here are model independent in the sense that they rely only on Isospin symmetry, following the Gronau-London proposal. A new bound on B 00 and the function C 00 (B 00 ) are introduced. While another bound applied to BABAR results is shown to imply that cos(2α eff ) is negative. The Grossman-Quinn bound is rediscussed. A close form expression is given for α as a function of the measurements. Various scenarii for the future of the isospin analysis are explored. To probe the Standard Model the (B 00 , C 00 ) plane is introduced.

Measurements of Branching Fractions and Dalitz Distributions forB0→D(*)±K0π∓Decays

“…Subsequent to the fit, possible residual backgrounds from combinatoric D and K Events appropriately weighted by Wsig (see text) to exhibit the signal distribution [9] are shown as solid points over which the fitted signal PDF is superimposed. For comparison, the mES distribution obtained with |∆E| < 25 MeV (2σ) is included (dotted points).…”

Improved Measurements ofCP-Violating Asymmetry Amplitudes inB0→π+π−Decays

“…Distributions of (a) m ES , (b) E, and (c) F for signal ÿ events (points with error bars), and (d) the distribution of F for q q background events, using the weighting technique described in Ref. [16]. Solid curves represent the corresponding PDFs used in the fit.…”

Measurement of the Branching Fraction and the CP-Violating Asymmetry for the Decay B0 to K0s pi0

“…The evaluation of the systematic uncertainties is described below. Figure 1 shows the background-subtracted distribu- [23]. Events contribute according to a weight constructed from the covariance matrix for the yields (N S and N B ) and the probability P S and P B for the event, computed without the use of the variable that is being displayed.…”