Related papers: Tracking down penguins at the poles
K to pi pi matrix elements of the electroweak operator Q_(27,1)^Delta I=3/2 are calculated on the RBC/UKQCD 32^3 x 64, L_s=16 lattices, using 2+1 dynamical flavors and domain wall fermions, with an inverse lattice spacing of a^(-1)=2.42(4)…
The effect of weak annihilation and u-quark penguin contribution on the branching ratio B -> K_1 gamma at next-to-leading order of alpha_s are calculated using LEET approach. It is shown that the value of LEET form factor remains the same…
In the calculation of non-leptonic weak decay rates, a "mismatch" arises when the QCD evolution of the relevant weak hamiltonian down to hadronic scales is performed in unquenched QCD, but the hadronic matrix elements are then computed in…
Based on the low energy effective Hamiltonian with generalized factorization, we calculate the new physics contributions to the branching ratios and CP-violating asymmetries of the two-body charmless hadronic decays $B \to PP, PV$ from the…
We report on the measurement of the decay $B\to K^{\star}\gamma$, lepton-flavor dependent angular analysis of the decay $B\to K^{\star}\ell\ell$, and search for the decays $B\to h\nu\nu$. All these analyses are performed on the 711…
Recent theoretical results of the standard model expectations on $\sin2\beta_{\rm eff}$ from penguin-dominated $b \to s$ decays are briefly reviewed.
Penguin effects in the CP asymmetries of $B^0_d\rightarrow \pi^+\pi^-$ , $\bd\rightarrow\rho^{\pm}\pi^{\mp}$ and $\bd\rightarrow a^{\pm}_1 \pi^{\mp}$ are studied as function of the CKM unitarity triangle $\alpha$. Despite a fairly small…
The question of the relative size of two independent penguin amplitudes is studied using the data on the B^+ to pi^+ K^*0, and B^+ to K^+ \bar{K}^*0 decays. Our discussion involves a Regge-phenomenology-based estimate of SU(3) breaking in…
We perform a study of matrix elements relevant for the Delta I=1/2 rule and the direct CP-violation parameter epsilon-prime from first principles by computer simulation in Lattice QCD. We use staggered (Kogut-Susskind) fermions, and employ…
New data analysis with Pauli blocking explains observation of CP violation in $B^o\rightarrow K\pi$ decays, absence in $B^{\pm} \rightarrow K\pi$ decays and gives new predictions agreeing with experiment. Branching ratio data show pure…
We present a preliminary measurement of the branching fraction of the exclusive penguin decay B^0 -> K^*0 gamma using (8.6+/-0.3) x 10^6 B-anti-B decays BF(B^0 -> K^*0 gamma) = (5.2+/-0.82 (stat.) +/- 0.47 (sys.)) x 10^-5. In addition we…
A search for the decays B --> rho(770) gamma and B0 --> omega(782)gamma is performed on a sample of 211x10^6 Y(4S)->BBbar events collected by the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring. No evidence for the decays…
We show that the CP-violating phases \beta and \beta' can respectively be determined from the time-dependent measurements of B_d \to D^*\pmD^\mp and B_s \to D^*\pm_sD^\mp_s decays, whose final states are non-CP eigenstates. The penguin…
We present a new analysis of the Delta I = 1/2 rule in K --> pi pi decays and the B_K parameter. We use the 1/N_c expansion within the effective chiral lagrangian for pseudoscalar mesons and compute the hadronic matrix elements at leading…
Theoretical errors in the extraction of alpha from B -> pi^+ pi^-, rho^+ rho^-, rho pi decays are usually given in terms of upper bounds on alpha_eff-alpha obtained from isospin or from SU(3) relations, where alpha_eff is measured through…
We present a numerical computation of matrix elements of DI=3/2 K-->pi pi decays by using Wilson fermions. In order to extrapolate to the physical point we work at unphysical kinematics and we resort to Chiral Perturbation Theory at the…
We discuss the implementation and properties of the quenched approximation in the calculation of the left-right, strong penguin contributions (i.e. Q_6) to epsilon'/epsilon. The coefficient of the new chiral logarithm, discovered by…
We present results for the \Delta S=2 matrix elements which are required to study neutral kaon mixing in the standard model (SM) and beyond (BSM). We also provide leading chiral order results for the matrix elements of the electroweak…
We calculate CP-violating rates and asymmetry parameters in charged and neutral $B\to \pi\pi, \pi K$ and $\bar K K$ decays arising from the interference of tree and penguin (strong and electroweak) amplitudes with different strong and CKM…
Recently, we pointed out that chiral transformation properties of strong penguin operators change in the transition from unquenched to (partially) quenched QCD. As a consequence, new penguin-like operators appear in the (partially) quenched…