Pietro Biassoni
We report measurements of Time-Dependent CP asymmetries in several $b\to s$ penguin dominated hadronic B decays, where New Physics contributions may appear. We find no significant discrepancies with respect to the Standard Model expectations.
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We summarize results on a number of observations of penguin dominated radiative decays of the B meson. Such decays are forbidden at tree level and proceed via electroweak loops. As such they may be sensitive to physics beyond the standard model. The observations have been made at the BaBar experiment at PEP-II, the asymmetric B factory at SLAC.
We report recent results in the study of rare hadronic and radiative penguin decays of B mesons. These results are based on a sample of 23 million B B-bar pairs collected by the BaBar Collaboration at the SLAC PEP-II e+e- B Factory.
We present recent results from the \babar Collaboration on radiative decays. These include searches for new physics via measurements of several observables such as the time-dependent $CP$ asymmetry in $B^0 \to K^0_S π^- π^+ γ$ exclusive decays, as well as direct $CP$ asymmetries and branching fractions in $B \to X_s γ$ and $B \to X_s \ell^+ \ell^-$ inclusive decays.
This article summarises measurements of time-dependent CP asymmetries in decays of neutral B mesons to charmonium, open-charm and gluonic penguin-dominated charmless final states. Unless otherwise stated, these measurements are based on a sample of approximately 230 million Y(4S) to BBbar decays collected by the BABAR detector at the PEP-II asymmetric-energy B-factory.
We report recent results from the BABAR experiment on semileptonic charmless B-meson decays and electroweak penguin processes. Semileptonic charmless decays are used to determine |Vub| and the exclusive modes considered here also begin to constrain QCD-lattice form factor calculations. Radiative penguin decays are both sensitive to physics beyond the Standard Model and can be used to extract Heavy Quark parameters related to the b-quark mass and its motion inside the hadron.
Electro-weak penguin and leptonic decays provide an indirect probe for physics beyond the Standard Model and contribute to the determination of Standard Model parameters. Copious quantities of B mesons produced at the B-Factories permit precision measurements of the electro-weak penguin decays and searches for leptonic decays. We review the current experimental status of b -> s(d) gamma, B^0 -> D^{*0} gamma, b -> s l^+ l^- and finally B->tau nu decays at BaBar.
We present preliminary measurements of time-dependent CP-violation parameters in the decays B0->omegaK0S, B0->eta'K0, B0->pi0K0S, B0->phiK0Spi0, and B0->K+K-K0S, which includes the resonant final states phiK0S and f0(980)K0S. The data sample corresponds to the full BABAAR dataset of 467 million BBbar pairs produced at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center.
Recent BaBar results on rare B decays involving flavour-changing neutral currents or purely leptonic final states are presented. New measurements of the CP asymmetries in B -> K* gamma, B -> K*2(1430) gamma, and b -> s gamma are reported, as well as a new measurement of the B -> K* gamma branching fraction. Also reported are updated limits on B -> mu nu and recent measurements of B -> K* l+ l- and b -> s l+ l-. The data sample comprises 123 10^6 Y4S -> B Bbar decays collected with the BaBar detector at the PEP-II e+e- storage ring.
We report measurements of charmonium resonances (J/Psi, Psi(2S),Chi_c1) using about 25 fb^-1 of data collected by the BABAR detector around the Upsilon(4S) resonance. We present measurements of inclusive charmonium production of charmonium in B decays and from the continuum, as well as exclusive branching ratios of B mesons into charmonium final states. We present also a measurement of the B0 -> K*0 gamma branching ratio and a search for the decay B0 -> gamma gamma.
Knowing the mass of the b-quark is essential to the study of the structure and decays of B mesons as well as to future tests of the Higgs mechanism of mass generation. We present recent preliminary measurements of the b-quark mass and related nonperturbative parameters from moments of kinematic distributions in charmed and charmless semileptonic and radiative penguin B decays. Their determination from charmless semileptonic B decays is the first measurement in this mode. The data were collected by the BABAR detector at the PEP-II asymmetric-energy e+e- -collider at the Stanford Linear Accelera…
Radiative and electroweak decays of B mesong (B to X_{s(d)}γ and B to X_{s(d)}\ell\ell, respectively, where X is a hadronic system and s or d labels the underlying quark process b to s(d)γ) provide good places to search for new physics (NP) beyond the standard model. Recent BaBar measurements are reported: inclusive BF(B to X_s γ), direct CP asymmetry for inclusive X_s γ and X_{s+d} γ, and searches for the rare decays B to π(η)\ell\ell. No evidence for NP was found, but several constraints are discussed.
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 search for the related penguin decays with a lepton pair in the final state, B^+ -> K^+ l^+l^-, B^0 -> K^*0 l^+l^-. We find no evidence for these decays in 3.7+/-0.1 x 10^6 B-anti-B decays and set preliminary 90% C.L upper limits of BF(B^+ -> K^+ e^+ e^-) < 12.5 x 10^{-6}, BF(B^+ -> K^+ mu^+ mu^-) < 8.3 x 10^{-6}, BF(B^0 -> K^*0 e^+ e^-) < 24.1 x 10^{-6}, BF(B…
We present the new and updated $BABAR$ measurements of CP-violation studies for many $b\to s $ penguin decay modes. We report the first observation of mixing-induced CP-violation in $B^0 \to η^{'} K^0$ with a significance (including systematic uncertainties) of 5.5$σ$. We also present the first observation of the decay $B^0 \to ρ^0 K^0$. Using the time-dependent Dalitz plot analysis of $B^0\to K^+K^- K^0$ decay, the CP-parameters $\mathcal A_{CP}$ and $β_{eff}$ are measured with $4.8σ$ significance, and we reject the solution near $π/2 - β_{eff}$ at $4.5σ$. We also present the updated measurem…
We report on preliminary results of searches for penguin mediated B decays based on 20.7 fb^{-1} of data collected at the Y(4S) peak with the BABAR detector at PEP-II. The following branching fractions have been measured: BR(B+ --> phi K+) = (7.7^{+1.6}_{-1.4} +- 0.8)*10^{-6}, BR(B0 --> phi K0) = (8.1^{+3.1}_{-2.5} +- 0.8)*10^{-6}, BR(B+ --> phi K*+) = (9.7^{+4.2}_{-3.4} +- 1.7)*10^{-6}, BR(B0 --> phi K*0) = (8.7^{+2.5}_{-2.1} +- 1.1)*10^{-6}, BR(B+--> omega pi+) = (6.6^{+2.1}_{-1.8} +- 0.7)*10^{-6}, BR(B --> eta K^*0) = (19.8^{+6.5}_{-5.6} +-1.7)*10^{-6}, where the first error is statistical …
This article gives an overview of the recent searches and measurements of $b\to d$ penguin transitions with the BaBar experiment. The branching fraction of these decays in the Standard Model (SM) is expected to be a factor of 10 or more lower than the corresponding $b\to s$ penguin transitions, but a deviation from the SM prediction would be an equally striking sign of new physics. The exclusive decay $B\toπ\ell\ell$ is searched by BaBar with no excess over the background found. The BaBar measurement of $B\to(ρ,ω)γ$ provides the first evidence of $B^+\toρ^+γ$, is in good agreement with the pre…
We discuss recent experimental studies of radiative penguin decays of B mesons by the Belle and BaBar collaborations.
The BABAR experiment has completed its first year of data-taking during which 21 $fb^{-1}$ of data were accumulated. We present preliminary results on two types of charmless B decays based on this data sample. The first, $B^0 \to K^{*0}γ$, is a so-called electromagnetic penguin. And the second, $B^0 \to h^+h^{'-}$, where $h^{(')}$ can be either a pion or kaon, can come from either penguin diagrams or Cabibbo suppressed tree diagrams.
We present measurements of branching fraction, polarization and charge asymmetry in charmless hadronic B decays with eta, eta', omega, and b_1 in the final state. All the results use the final BABAR dataset.
Proceedings of CKM 2012, the 7th International Workshop on the CKM Unitarity Triangle, University of Cincinnati, USA, 28 September - 2 October 2012.
We present recent results from the BaBar collaboration in several areas of research. These include searches for new physics via measurements of radiative-penguin B decays, lepton-number and lepton-flavor violations in B decays, and CP violation in tau lepton decays.
Based on 471 million BB pairs collected with the BABAR detector at the PEP-II e+e- collider, we perform a series of measurements on rare decays B->K(*)l+l-, where l+l- is either e+e- or mu+mu-. The measurements include total branching fractions, and partial branching fractions in six bins of di-lepton mass-squared. We also measure isospin asymmetries in the same six bins. Furthermore, we measure direct CP and lepton flavor asymmetries for di-lepton mass below and above the J/Psi resonance. Our measurements show good agreement with both Standard Model predictions and measurements from other exp…
We present preliminary measurements of CP-violating asymmetries in B decays. These include new results on the CKM angle alpha based on studies of the decay B -> rho+ rho- and several charmonium and hadronic penguin modes, sensitive to the CKM angle beta, including results on B -> phi K0S, B -> K+K-K0, B -> eta' K0S, B -> f0 K0, and B -> pi0 K0S. We also report on several of results related to the extraction of gamma and (2*beta+gamma) and present limits on CPT violation in B decays.
We present a preliminary measurement of the Collins asymmetries in the inclusive process e^+e^- --> qqbar --> pi pi X at center-of-mass energy near 10.6 GeV. We use a data sample of 468 fb^(-1) collected by the BABAR experiment, and we consider pairs of charged pions produced in opposite jets in hadronic events. We confirm a non-zero Collins effect as observed by previous experiments, and we study the Collins asymmetry as a function of pion fractional energies and transverse momenta, and as a function of the polar angle of the analysis axis.
We present measurements of Collins asymmetries in the inclusive process e+e- -->pi pi X, where pi stands for charged pions, at a center-of-mass energy of 10.6 GeV. We use a data sample of 468 fb-1 collected by the BABAR experiment at the PEP-II B factory at SLAC, and consider pairs of charged pions produced in opposite hemispheres of hadronic events. We observe clear asymmetries in the distributions of the azimuthal angles in two distinct reference frames. We study the dependence of the asymmetry on several kinematic variables, finding that it increases with increasing pion momentum and moment…
We report on preliminary measurements of time-dependent CP asymmetries in neutral B decays to CP eigenstates with transition amplitudes that are dominated by penguin-type loops. The results are obtained from a data sample of up to 227 million Upsilon(4S)->BB-bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson Factory at SLAC. The amplitudes of the effective mixing-induced CP asymmetries, sin(2beta)_eff, are derived from decay-time distributions of events in which one neutral B meson is fully reconstructed in a final state without charm and the other B meson is …
Transversity distribution describes the quark transverse polarization inside a transversely polarized nucleon. It is the less known leading-twist piece of the QCD description of the partonic structure of the nucleon. Transversity can be extracted from semi-inclusive deep inelastic scattering (SIDIS) where, however, it couples to a new, unknown fragmentation function, called Collins function. We present the preliminary results of the measurement of the azimuthal asymmetries in the process e^+e^- -> qqbar -> pi pi X, where the two pions are produced in opposite hemispheres. These preliminary res…
In this article, I review the most recent results in radiative penguin decays from the B factories Belle and Babar. Most notably, I will talk about the recent new observations in the decays B -> (rho/omega) gamma, a new analysis technique in b -> s gamma, and first measurements of radiative penguin decays in the B_s meson system. Finally, I will summarize the current status and future prospects of radiative penguin B physics at the B factories.
We report on a preliminary measurement of time-dependent CP-violating asymmetries in B0 --> J/psi K0S and B0 --> psi(2S) K0S decays recorded by the BABAR detector at the PEP-II asymmetric B Factory at SLAC. The data sample consisted of 9.0 fb-1 collected at the Y(4S) resonance and 0.8 fb-1 off-resonance. One of the pair of neutral B mesons produced at the Y(4S) was fully reconstructed, while the flavor of the other neutral B meson was tagged at the time of its decay. The value of the asymmetry amplitude, sin(2beta), was determined from a maximum likelihood fit to the time distribution of 120 t…
Recent branching fraction and asymmetry results of Electroweak Penguin B decays from BaBar, Belle and CLEO experiments are reviewed. While these branching fractions are consistent with the Standard Model expectations and are being used to extract heavy quark model parameters and CKM matrix elements, the asymmetry results are just becoming sensitive to observe any new physics effects.
We present a study of B--> D0(CP)K- decays, where D0(CP) is reconstructed in non-CP (K-pi+), CP-even (K-K+,pi-pi+) and CP-odd (KS0 pi0) eigenstates, based on a sample of about 214 million Y(4S) -> BBbar decays collected with the BABAR detector at the PEP-II e+e- storage ring. We measure the ratios of branching fractions R+ = [Br(B- ->D0_CP+ K-)+Br(B+ ->D0_CP+ K+)]/[Br(B- ->D0 K-)] = 0.87 +/- 0.14(stat) +/- 0.06(syst), R- = [Br(B- ->D0_CP- K-)+Br(B+ ->D0_CP- K+)]/[Br(B- ->D0 K-)] = 0.80 +/- 0.14(stat) +/- 0.08(syst), and the CP asymmetries A_CP+ = 0.40 +/- 0.15 (stat) +/- 0.08 (syst) and A_CP- …
We present measurements related to the CKM angle beta from BABAR based on 82 or ~115 fb-1 data samples collected at the PEP-II e+e- asymmetric B Factory collider. A new method allowing to measure the sign of cos(2.beta) with B0->J/Psi"K*0" events is explained and related results reported. Recent CP measurements in the penguin dominated modes B0->phi K0,B0->K+K-K0s, B0->pi0 K0s and B0->f0(980) K0s are presented.
The use of triple-product correlations is described in relation to the search for $CP$ violation in 4-body charm meson decays. The latest results from the LHCb and BaBar Collaborations are reported. A novel interpretation of the asymmetries from triple-product correlations is used for the BaBar results, which enables the extraction of information on the properties of $D$ decays under parity and charge-conjugation transformations.
Electromagnetic radiative penguin decays of the B meson were studied with the BaBar detector at SLAC's PEP-II asymmetric-energy B Factory. Branching fractions and isospin asymmetry of the decay B -> K* gamma, branching fractions of B -> K2*(1430) gamma, and a search for B0 -> phi gamma are presented. The decay rates may be enhanced by contributions from non-standard model processes.
Charmless $B$ decays are dominated by contributions from the short distance amplitudes from tree level and penguin loop-level amplitudes. The Tree contribution presents a weak phase $γ$. The relationship between these two amplitudes can generated a CP asymmetry depending from the relative amount among them in a particular decay. In multi-body charmless $B$ decays, these relative contribution can change along the phase space, given a non isotropic distribution of CP asymmetries in the Dalitz plot. Two recent LHCb analyses involving charmless multi-body B decays are discussed: the obsevation of …
Determination of the CP-violating parameters \sin 2βand \sin 2β' is shown to be possible from B^0_d vs \bar{B}^0_d \to D^{*+}D^{*-} and B^0_s vs \bar{B}^0_s \to D^{*+}_sD^{*-}_s decays {\it without} doing the angular analysis. The P-wave dilution factors of these two asymmetries are found to be 0.89 and 0.90, respectively, using the factorization approximation and heavy quark symmetry. The penguin-induced corrections amount to about 2% and 3% in the corresponding B_d and B_s channels. Final-state rescattering effects could be handled by detecting the neutral modes B^0_d and \bar{B}^0_d \to D^{…
The computation of direct CP asymmetries in charmless B decays at next-to-next-to-leading order (NNLO) in QCD is of interest to ascertain the short-distance contribution. Here we compute the two-loop penguin contractions of the current-current operators Q_{1,2} and provide a first estimate of NNLO CP asymmetries in penguin-dominated b -> s transitions.
We present the results of searches for rare B meson decays. The measurements use all or part of a data sample of about 88 million $Υ(4S)\to B{\bar B}$ decays collected between 1999 and 2002 with the \babar detector at the PEP-II asymmetric energy B Factory at the Stanford Linear Accelerator Center. We study a variety of decays dominated by electromagnetic, electroweak and gluonic penguin transitions, and report measurements of branching fractions and other quantities of interest.
A sample of 23 million B B-bar events collected with the BABAR detector at the PEP-II collider is used in a search for direct CP violation in charmless two-body B decays, quasi two-body B decays, and the radiative penguin decays B to K* gamma. No evidence for direct CP violation is found in the considered modes and 90% confidence level limits are reported. We also present a limit on the branching fraction of the decay B0 to gamma gamma.
This article summarises measurements of time-dependent CP asymmetries in decays of neutral B mesons to charm final states using data collected by the BaBar detector at the PEP-II asymmetric-energy B-factory. All results are preliminary unless otherwise stated.
We present an update on total and partial branching fractions and on CP asymmetries in the semi-inclusive decay B -> Xs l+l-. Further, we summarize our results on branching fractions and CP asymmetries for semi-inclusive and fully-inclusive B -> Xs gamma decays. We present the first result on the CP asymmetry difference of charged and neutral B -> Xs gamma$ decays yielding the first constraint on the ratio of Wilson coefficients Im (C8/C7).
Recent BaBar results on rare B decays involving flavour-changing neutral currents are presented. New measurements of the CP asymmetries in $b \to s γ$ decays are reported as well as $b \to s l^+l^-$ branching ratio measurements.
We report on measurements of time-dependent CP-violation asymmetries in neutral B meson decays to charmonium and charm final states. The results are obtained from a data sample of 467+/-5 million Y(4S)->BBbar decays collected with the BaBar detector at the PEP-II B factory.
We report recent measurements of branching fractions and charge asymmetries of charmless hadronic B decays using the data collected with the BABAR detector at the PEP-II asymmetric energy e+e- collider.
Recent measurements of branching fractions and CP-violating partial-rate asymmetries for rare hadronic B-meson decays by the asymmetric-energy B-factory experiments, Belle and BaBar, are reviewed.
We report on our recent measurements of the Cabibbo-Kobayashi-Maskawa CP-violating phase gamma and of related CP-asymmetries and branching fraction ratios. The measurements have been performed on samples of up to 465 million BBbar pairs collected by the BaBar detector at the SLAC PEP-II asymmetric-energy B factory in the years 1999-2007.
We summarise the most recent results of the Belle experiment about flavour changing neutral current (FCNC) radiative and (semi-) leptonic B decays. In particular, we report about the first observation of the decays B->K*l+l-, B->phi K gamma, the inclusive B->Xs l+l-$. We also report about searches for B->l+l- decay and for CP asymmetries in B->K*gamma.
I present some of the most recent BaBar measurements for rare B decays. These include rate asymmetries in the B decays to K(*) l+ l- and K+ pi- and branching fractions in the B decays to l+ nu_l, K_1(1270)+ pi- and K_1(1400)+ pi-. I also report a search for the B+ decay to K0_S K0_S pi+.
We present recent results on time integrated and time dependent CP violation for charmless hadronic B decays using BABAR detector at the PEP-II B-factory.
Using a sample of 227 million $Υ(4S) \to B \bar{B}$ events collected with the $BABAR$ detector at the PEP-II $B$ Factory in 1999--2004, we study $B^- \to D^0 K^*(892)^-$ decays where $K^{*-} \to K^0_S π^-$ and $D^0 \to K^-π^+, K^- π^+ π^0, K^-π^+ π^+ π^-$ (non-CP final states), $K^+ K^-, π^+ π^- (CP+$ eigenstates), $K^0_S~π^0, K^0_S ϕ$ and $K^0_S ω(CP-$ eigenstates). The partial rate charge asymmetries $\mathcal{A}_{CP}$ and the ratios $\mathcal{R}_{CP}$ defined in the literature as the sum of the $B^+$ and $B^-$ partial rates to a charged $K^*$ and a $D^0 CP$-eigenstate divi ded by the $B \to…
We present recent results on charmless hadronic B decays using data collected by the BaBar detector at the PEP-II asymmetric-energy e+e- collider at the Stanford Linear Accelerator Center. We report measurements of branching fractions and charge asymmetries in several charmless two-body, three-body, and quasi-two-body decay modes. We also report measurements of polarization in charmless B decays to exclusive final states with two vector mesons.
We provide Standard Model expectations for the rare radiative decays B->K^* gamma, B->rho gamma and B-> omega gamma, and the electroweak penguin decays B->K^* l^+ l^- and B->rho l^+ l^- at the next-to-leading order (NLO), extending our previous results to b->d transitions. We consider branching fractions, isospin asymmetries and direct CP asymmetries. For the electroweak penguin decays, the lepton-invariant mass spectrum and forward-backward asymmetry is also included. Radiative and electroweak penguin transitions in b->d are mainly interesting in the search for new flavour-changing neutral cu…
We present updated results on time-dependent CP-violating asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 62 million Y(4S) --> B Bbar decays collected between 1999 and 2001 with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure sin2beta = 0.75 +/- 0.09 (stat) +/- 0.04 (syst) and |lambda| = 0.92 +/- 0.06 (stat) +/- 0.02 (syst).
We report on preliminary measurements of time-dependent CP-violation asymmetries in charmless neutral B meson decays to K+K-K0 (including resonant decays phiK0 and f0K0), eta'K0, pi0K0s, K0sK0sK0s, K0sK0s, rho0K0s, omegaK0s. The results are obtained from a data sample of up to 347 million BBbar pairs produced by e+e- annihilation at the Y(4S) resonance collected with the BaBar detector at the PEP-2 asymmetric-energy B-meson Factory at SLAC.
Recent results from BaBar and Belle experiments on $B \bar B$ mixing and $\sin 2ϕ_1$ are presented. Accuracy of $Δm_d$ measurements has reached 1.2%. Higher order effects within the Standard Model or possible new physics effect that might appear in the $B \bar B$ mixing through non-zero $ΔΓ/Γ$, CP violation, or $CPT$ violation have been explored. The BaBar and Belle results on $\sin 2ϕ_1$ from the $b \to c \bar{c} s$ modes are in good agreement with each other and a combined result with an accuracy of 8% is in good agreement with a global CKM fit. A simple average of the $\sin 2ϕ_1$ values tha…
A first measurement of time-reversal (T) asymmetries that are not also CP asymmetries has been recently achieved by the BaBar collaboration. We analyze the measured asymmetries in the presence of direct CP violation, CPT violation, wrong strangeness decays and wrong sign semileptonic decays. We note that the commonly used S_{ψK} and C_{ψK} parameters are CP-odd, but have a T-odd CPT-even part and a T-even CPT-odd part. We introduce parameters that have well-defined transformation properties under CP, T and CPT. We identify contributions to the measured asymmetries that are T conserving. We exp…
We present improved measurements of the branching fractions and CP asymmetries in the two-body decays B0 --> pi0 pi0, B0 --> K0 pi0 and B0 --> K+ pi- as well as the quasi two-body B0 --> K_1(1270)+ pi- and B0 --> K_1(1400)+ pi- decays. These updated measurements are made using the complete set of BABAR data taken at the Y(4S) resonance, collected between 1999 and 2007 at the PEP-II collider at SLAC.
The huge datasets collected at the two B factories, Belle and BaBar, have made it possible to explore the radiative penguin process b --> s gamma, the electroweak penguin process b --> s l+ l- and the suppressed radiative process b --> d gamma in detail, all in exclusive channels and inclusive measurements. Theoretical tools have also advanced to meet or surpass the experimental precision, especially in inclusive calculations and the various ratios of exclusive channels. In this article, we review the theoretical and experimental progress over the past decade in the radiative and electroweak p…
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 is seen. We set the following limits on the individual branching fractions: BF(B --> rho+ gamma)<1.8 x 10^-6, BF(B --> rho0 gamma)<0.4 x 10^-6, and BF(B --> omega gamma)<1.0 x 10^-6 at the 90% confidence level (C.L.). We use the quark model to limit the combined branching fraction BFbar[B --> (rho/omega) gamma]<1.2 x 10^-6, from which we determine a constrain…
The decay $B^0 \to K^0 π^0$, dominated by a $b \to s$ penguin amplitude, holds the potential for exhibiting new physics in this amplitude. In the pure QCD penguin limit one expects $\ckp = 0$ and $\skp = \sin 2 β$ for the coefficients of $\cos Δm t$ and $\sin Δm t$ in the time-dependent CP asymmetry. Small non-penguin contributions lead to corrections to these expressions which are calculated in terms of isospin-related $B\to Kπ$ rates and asymmetries, using information about strong phases from experiment. We study the prospects for incisive tests of the Standard Model through examination of t…
The BABAR collaboration measurements of the B -> pipi, B -> rhopi and B -> rhorho decays are presented. New results, from a 113 fb-1 data sample, on the time-dependent CP asymmetries of the longitudinally polarized component of the B0 -> rho+rho- channel are S_{rhorho,long}=-0.19 +/- 0.33 +/- 0.11 and C_{rhorho,long}=-0.23 +/- 0.24 +/- 0.14. Constraints on the Unitarity Triangle angle alpha from the pipi and the rhorho systems are derived.
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