Charmless hadronic decays of B mesons to a pseudoscalar and a tensor meson

We study two-body charmless hadronic decays of B mesons to a pseudoscalar meson (P) and a tensor meson (T) in the frameworks of both flavor SU(3) symmetry and generalized factorization. Certain ways to test the validity of the generalized factorization are proposed, based on the flavor SU(3) analysis. We present a set of relations between a flavor SU(3) amplitude and the corresponding amplitude in the generalized factorization which bridge both approaches in decays. The branching ratios and CP asymmetries are calculated using the full effective Hamiltonian including all the penguin operators and the form factors obtained in the non-relativistic quark model of Isgur, Scora, Grinstein and Wise. We identify the decay modes in which the branching ratios and CP asymmetries are expected to be relatively large. Received: 6 July 2001 / Revised version: 8 October 2001 / Published online: 30 November 2001     

Nonfactorizable contributions to weak D → PV decays

We investigate nonfactorizable contributions to two-body hadronic decays of the charmed mesons to a pseudoscalar meson and a vector meson in Cabibbo-favored, Cabibbo-suppressed and Cabibbo-doubly suppressed modes. Employing SU(3)-flavor symmetry for the nonfactorizable matrix elements, we obtain branching ratios of the decays in consistent agreement with experiment.     

CP-violating asymmetries inη′K and direct CP violation searches with BABAR in charmless hadronicB meson decays

We present preliminary results of the measurement of branching fractions and CP violating asymmetries inB meson decays toη′K and ØK*. We update also the results of the direct CP violation searches with BABAR in charmless hadronicB meson decays.     

Chiral perturbation theory for fDS/FD and BBS/BB

The decay constants for D and D_s mesons, denoted f_D and f_DS respectively, are equal in the SU(3)_V limit, as are the hadronic amplitudes for and mixing. The leading SU(3)_V violating contribution to (F_DS/F_D) and to the ration of hadronic matrix elements relevant for and mixing amplitudes are calculated in chiral perturbatiion theory. We discuss the formalism needed to include both meson and anti-meson fields in the heavy quark effective theory.     

Evidence for B0 s-->phiphi decay and measurements of branching ratio and A(CP) for B+ -->phiK+

We present the first evidence of charmless decays of the B(0)(s) meson, the decay B(0)(s)--> phiphi, and a measurement of the branching ratio BR(B(0)(s)--> phiphi) using 180 pb(-1) of data collected by the CDF II experiment at the Fermilab Tevatron collider. In addition, the BR and direct CP asymmetry for the B+-->phiK+ decay are measured. We obtain BR(B(0)(s)--> phiphi)=[14(+6)(-5)(stat)+/-6(syst)] x 10(-6), BR(B+-->phiK+)=[7.6+/-1.3(stat)+/-0.6(syst)] x 10(-6), and A(CP)(B+-->phiK+)= -0.07+/-0.17(stat)+0.03 / -0.02(syst). Both decays are governed in the standard model by second order (penguin) b-->s(-)ss amplitudes.     

Hadronic B decays to charmless VT final states

Charmless hadronic decays of B mesons to a vector meson (V) and a tensor meson (T) are analyzed in the frameworks of both flavor SU(3) symmetry and generalized factorization. We also make comments on B decays to two tensor mesons in the final states. Certain ways to test the validity of the generalized factorization are proposed, using decays. We calculate the branching ratios and CP asymmetries using the full effective Hamiltonian including all the penguin operators and the form factors obtained in the non-relativistic quark model of Isgur, Scora, Grinstein and Wise. Received: 6 July 2001 / Revised version: 8 October 2001 / Published online: 7 December 2001     

Weak annihilation and the effective parameters <Emphasis Type="Italic">a</Emphasis><Subscript>1</Subscript> and <Emphasis Type="Italic">a</Emphasis><Subscript>2</Subscript> in non-leptonic <Emphasis Type="Italic">D</Emphasis> decays

Based on SU(3) flavor symmetry, many of the quark-graph amplitudes in two-body non-leptonic decays of charmed mesons can be extracted from experiment, which enable us to see the relevance and importance of weak annihilation topologies and to determine the complex parameters a₁ and a₂ to test the factorization approach. It is found that a ₂ /a ₁ in and can be different by a factor of 2, indicating that non-factorizable corrections to the latter are far more important than the former. The relative phase between a₁ and a₂ is about 150°. Weak annihilation topologies induced by nearby resonances via final-state rescattering can be described in a model-independent manner. Although the W-exchange contribution in decays is dominated by resonant final-state interactions (FSIs), its amplitude in VP decays (V: vector meson, P: pseudoscalar meson) receives little contributions from FSIs in the quark-antiquark resonance formation. As a consequence, the sign flip of the W-exchange amplitude in and decays, which is needed to explain the relatively real decay amplitudes of , remains unexplained. SU(3) symmetry is badly broken in some Cabibbo-suppressed modes and this can be accounted for by the accumulation of some modest SU(3) violation in individual quark-graph amplitudes. Received: 19 July 2002 / Published online: 20 November 2002     

Study of exclusive radiative B meson decays

We have studied exclusive, radiative B meson decays to charmless mesons in 9.7x10(6) B&Bmacr; decays accumulated with the CLEO detector. We measure B(B0-->K(*0)(892)gamma) = (4.55(+0.72)(-0. 68)+/-0.34)x10(-5) and B(B+-->K(*+)(892)gamma) = (3.76(+0.89)(-0. 83)+/-0.28)x10(-5). We have searched for CP asymmetry in B-->K(*)(892)gamma decays and measure A(CP) = +0.08+/-0.13+/-0.03. We report the first observation of B-->K(*)(2)(1430)gamma decays with a branching fraction of (1.66(+0.59)(-0.53)+/-0.13)x10(-5). No evidence for the decays B-->rhogamma and B0-->omegagamma is found and we limit B(B-->(rho/omega)gamma)/B(B-->K(*)(892)gamma)<0.32 at 90% C.L.     

Vector states in e+e− annihilation at 3.9–4.5 GeV

The structure observed at SPEAR in e⁺e^? annihilation in the energy range 3.9–4.5 GeV is explained in an SU(8) × SL(3, R) color quark model. The model can account for the mass differences, total hadronic and leptonic widths, as well as for the rise in, and the magnitude of, R. Main predictions are the SU(3) properties of these states, strong suppression of their decays into the ψ(3.1) and the existence of another vector meson around 6 GeV.     

Rates, polarizations, and asymmetries in charmless vector-vector B meson decays

With a sample of approximately 89 x 10(6) B(-)B pairs collected with the BABAR detector, we perform a search for B meson decays into pairs of charmless vector mesons (phi, rho, and K*). We measure the branching fractions, determine the degree of longitudinal polarization, and search for CP violation asymmetries in the processes B+-->phiK(*+), B0-->phiK(*0), B+-->rho(0)K(*+), and B+-->rho(0)rho(+). We also set an upper limit on the branching fraction for the decay B0-->rho(0)rho(0).     

Proton decay in terms of an effective baryon-lepton transition

We calculate the two-body decay rates for the hadronic and electromagnetic decays of proton and neutron in terms of the effective baryon-lepton transition matrix element. Further ingredients like PCAC and vector meson dominance are used. We compute these transition amplitudes within the framework of a relativistic quark model involving Bethe-Salpeter amplitudes and present the nucleon lifetimes and branching ratios of various decay modes for three different grand unification models.     

Observation of B --> K(+/-) pi(0) and B --> (K)0 pi(0), and evidence for B --> pi(+)pi(-)

We have studied charmless hadronic decays of B mesons into two-body final states with kaons and pions and observe three new processes with the following branching fractions: beta(B-->pi(+)pi(-)) = (4.3(+1. 6)(-1.4)+/-0.5)x10(-6), beta(B-->K(0)pi(0)) = (14.6(+5.9+2.4)(-5.1-3. 3))x10(-6), and beta(B-->K(+)/-pi(0)) = (11.6(+3.0+1.4)(-2.7-1.3))x10(-6). We also update our previous measurements for the decays B-->K(+)/-pi(-/+) and B+/--->K(0)pi(+/-).     

Implications of the LHCb evidence for charm CP violation

The LHCb collaboration recently announced preliminary evidence for CP violation in D meson decays. We discuss this result in the context of the standard model (SM), as well as its extensions. In the absence of reliable methods to evaluate the hadronic matrix elements involved, we can only estimate qualitatively the magnitude of the non-SM tree level operators required to generate the observed central value. In the context of an effective theory, we list the operators that can give rise to the measured CP violation and investigate constraints on them from other processes.     

Measurement of the inclusive charmless semileptonic branching ratio of B mesons and determination of |V ub|

We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample of 89 x 10(6) (-)BB events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson. The number of signal events is extracted from the mass distribution of the hadronic system accompanying the lepton and is used to determine the ratio of branching fractions B((-)B-->X(u)lnu;)/B((-)B-->Xlnu;)=[2.06+/-0.25(stat)+/-0.23(syst)+/-0.36(theo)]x10(-2). Using the measured branching fraction for inclusive semileptonic B decays, we find B((-)B-->X(u)lnu;)=[2.24+/-0.27(stat)+/-0.26(syst)+/-0.39(theo)]x10(-3) and derive the Cabibbo-Kobayashi-Maskawa matrix element |V(ub)|=[4.62+/-0.28(stat)+/-0.27(syst)+/-0.48(theo)]x10(-3).     

Determinations of from inclusive semileptonic decays with reduced model dependence

We report two novel determinations of /|Vub/ with reduced model dependence, based on measurements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from Upsilon(4S)-->BB events. In one approach, we combine the inclusive B-->Xulambdav rate, integrated up to a maximum hadronic mass mX<1.67 GeV/c2, with a measurement of the inclusive B-->Xsgamma photon energy spectrum. We obtain /Vub/=(4.43+/-0.38stat+/-0.25syst+/-0.29theo) x 10-3. In another approach we measure the total B-->Xulambdav rate over the full phase space and find /Vub/=(3.84+/-0.70stat+/-0.30syst+/-0.10theo) x 10-3.     

Study of charmless hadronic B meson decays to pseudoscalar-vector final states

We report results of searches for charmless hadronic B meson decays to pseudoscalar( pi(+/-), K+/-, pi(0), or K(0)(S))-vector( rho, K(*), or omega) final states. By using 9.7x10(6) BB pairs collected with the CLEO detector, we report the first observation of B(-)--->pi(-)rho(0), B(0)-->pi(+/-)rho(-/+), and B(-)-->pi(-)omega, which are expected to be dominated by hadronic b-->u transitions. The measured branching fractions are (10.4(+3.3)(-3.4)+/-2.1)x10(-6), (27.6(+8.4)(-7.4)+/-4.2)x10(-6), and (11.3(+3.3)(-2.9)+/-1. 4)x10(-6), respectively. Branching fraction upper limits are set for all of the other decay modes investigated.     

Isospin amplitudes and CP violation in (B \to K \pi) decays

We present a simple isospin invariant parametrization for decay amplitudes which consistently includes CP violation and (quasi-elastic) hadronic final state interactions. We find that the observed decays do not lead to a significant bound on the angle of the unitarity triangle. On the other hand, we claim that a sizeable CP violation asymmetry in rates is by no means excluded. Received: 9 June 1998 / Published online: 8 September 1998     

SU(N) elastic rescattering in B and D decays

The treatment of elastic final-state interactions (FSIs) under a symmetry group is presented. The proposed model is based on Watson's theorem, i.e. on symmetry properties of the -matrix and on its unitarity. This theorem provides an easy way to introduce rescattering effects by defining final-state interactions mixing matrices. A symmetry group fixes the structure of such mixing matrices, and the passage from one group to another is studied (for example, SU(2) to SU(3)). Mixings among two charmless pseudoscalar decay product states will be systematically analyzed. Finally, these mixing matrices will be used on quark diagram parametrizations of B and D decay amplitudes. This will have some important consequences on the definition of quark diagrams. It will be argued that these diagrams should not contain any FSI effects, i.e. they should be real (except for CKM factors). FSIs are then introduced at the hadronic level, by mixing basic quark diagram topologies. Received: 17 December 1998 / Revised version: 17 February 1999 / Published online: 28 September 1999     

Grand unification of quark and lepton flavor changing neutral currents

In the context of supersymmetric grand unified theories with soft breaking terms arising at the Planck scale, it is generally possible to link flavor changing neutral current and CP violating processes occurring in the leptonic and hadronic sectors. We study the correlation between flavor changing squark and slepton mass insertions in models à la SU(5). We show that the constraints coming from lepton flavor violation exhibit a strong impact on CP-violating B decays.     

Tensor Meson Dominance and e+e−-Physics

We report on the phenomenological status of tensor meson dominance. Some new results, mainly concerning hadronic decays of the 2⁺⁺-meson χ₂(3.55) and the heavy lepton τ are also included. Considering experimental errors, we find agreement of tensor meson dominance with experiment.