CKM angles from non-leptonic B decays using SU(3) flavour symmetry

We discuss the determination of the CKM angles gamma and alpha using recent data from non-leptonic B decays together with flavour symmetries. Penguin effects are controlled by means of the CP-averaged branching ratio B_d \to \pi^\pm K^\mp. The information from A_{CP}(B_d \to J/\Psi K_S) (two solutions for phi_d), Rb and gamma allow us to determine beta, even in presence of New Physics not affecting Delta B=1 amplitudes. In this context we address the question of to what extent there is still space for New Physics.Comment: 3 pages, 2 figures, Invited talk given at International Europhysics Conference on High-Energy Physics (HEP 2003), Aachen, Germany, 17-23 Jul 200

Exploiting the Symmetries of P and S wave for B --> K^* mu^+ mu^-

After summarizing the current theoretical status of the four-body decay B --> K^*(--> K pi) mu^+ mu^-, we apply the formalism of spin-symmetries to the full angular distribution, including the S-wave part involving a broad scalar resonance K0^*. While we recover in the P-wave sector the known relation between the angular observables Pi('), we find in the S-wave sector two new relations connecting the coefficients of the S-wave angular distribution and reducing the number of independent S-wave observables from six to four. Included in the experimental data analysis, these relations can help to reduce the background from S-wave pollution. We further point out the discriminative power of the maximum of the angular observable P2 as a charm-loop insensitive probe of right-handed currents. Moreover, we show that in absence of right-handed currents the angular observables P4' and P5' fulfill the relation P4' = beta P5' at the position where P2 reaches its maximum.Comment: 13 pages, 3 figures; journal versio

A new relation between the zero of AFBA_{FB} in B0→K∗μ+μ−B^0 \to K^* \mu^+\mu^- and the anomaly in P5′P_5^\prime

We present two exact relations, valid for any dilepton invariant mass region (large and low-recoil) and independent of any effective Hamiltonian computation, between the observables $P_i$ and $P_i^{CP}$ of the angular distribution of the 4-body decay $B \to K^*(\to K\pi) l^+l^-$. These relations emerge out of the symmetries of the angular distribution. We discuss the implications of these relations under the (testable) hypotheses of no scalar or tensor contributions and no New Physics weak phases in the Wilson coefficients. Under these hypotheses there is a direct relation among the observables $P_{1}$,$P_2$ and $P_{4,5}^\prime$. This can be used as an independent consistency test of the measurements of the angular observables. Alternatively, these relations can be applied directly in the fit to data, reducing the number of free parameters in the fit. This opens up the possibility to perform a full angular fit of the observables with existing datasets. An important consequence of the found relations is that a priori two different measurements, namely the measured position of the zero ($q_0^2$) of the forward-backward asymmetry $A_{FB}$ and the value of $P_5^\prime$ evaluated at this same point, are related by $P_4^2(q_0^{2})+P_5^2(q_0^{2})=1$. Under the hypotheses of real Wilson coefficients and $P_4^\prime$ being SM-like, we show that the higher the position of $q_0^{2}$ the smaller should be the value of $P_5^\prime$ evaluated at the same point. A precise determination of the position of the zero of $A_{FB}$ together with a measurement of $P_4^\prime$ (and $P_1$) at this position can be used as an independent experimental test of the anomaly in $P_5^\prime$. We also point out the existence of upper and lower bounds for $P_1$, namely $P_5^{\prime 2}-1 \leq P_1 \leq 1-P_4^{\prime 2}$, which constraints the physical region of the observables.Comment: 5 pages, 3 figure