[en] The final-state interaction in multichannel decay processes is systematically studied with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like 'Watson's theorem' holds for experimentally observed final states. We first examine in detail the two-channel problem as a toy-model to clarify the issues and to remedy common mistakes made in earlier literature. Realistic multichannel problems are too challenging for quantitative analysis. To cope with mathematical complexity, we introduce a method of approximation that is applicable to the case where one prominent inelastic channel dominates over all others. We illustrate this approximation method in the amplitude of the decay B to pi K fed by the intermediate states of a charmed meson pair. Even with our approximation we need more accurate information of strong interactions than we have now. Nonetheless we are able to obtain some insight in the issue and draw useful conclusions on general features on the strong phases

[en] Two-channel final-state interaction problem is exactly solved and applied to the B meson decay. The final-state interaction in multichannel decay processes is systematically studied in the hadronic picture with application to B decay in mind. Since the final-state interaction is intrinsically interwoven with the decay interaction in this case, no simple phase theorem like 'Watson's theorem' holds for experimentally observed final states. We first solve exactly the two-channel problem as a toy model in order to clarify the issues. The constraints of the two-channel approximation turns out to be too stringent for most B decay modes, but realistic multichannel problems are too complex for useful quantitative analysis at present. To alleviate the stringent constraints of the two-body problem and to cope with complexity beyond it, we introduce a method of approximation that is applicable to the case where one prominent inelastic channel dominates over all others. We illustrate this approximation method with the amplitude of the decay B → Kπ fed by the intermediate states of a charmed-meson pair. Even with our approximation we need more accurate information of strong interactions than we have now. Nonetheless we are able to obtain some insight in the issue and draw useful conclusions on general features on the strong phases

[en] It has been argued that the mystery boson X(3872) is a molecular state consisting of primarily D⁰(bar D)*⁰ + (bar D)⁰D*⁰. In contrast, apparent puzzles and potential difficulties have been pointed out for the charmonium assignment of X(3872). They examine several aspects of these alternatives by semi-quantitative methods since quantitatively accurate results are often hard to reach on them. they point out that some of the observed properties of X(3872), in particular, the binding and the production rates are incompatible with the molecule interpretation. Despite puzzles and obstacles, X(3872) may fit more likely to the excited ³P₁ charmonium than to the molecule after the mixing of c(bar c) with D(bar D)* + (bar D)D* is taken into account

No abstract available

[en] Following a brief survey of nongauge interactions of composite W and Z from a theoretical viewpoint, we point out some of conspicuous signatures of compositeness at supercolliders, in particular Wγ and Zγ production through q anti q by interactions of dimension six. In these processes, a suppression factor 1/Λ² due to compositeness scale Λ is largely compensated by longitudinal polarizations of W and Z, allowing us to probe up to high values of Λ. 10 refs., 3 figs

No abstract available

[en] Extending the dynamics underlying the factorization calculation of two-body decays, we propose simple selection rules for nonresonant three-body B decays. We predict, for instance, that in the Dalitz plot of B⁰→bar D⁰π⁺π^-, practically no events should be found in the corner region of E(π⁺)≤Λ_QCD as compared with the corner of E(π^-)≤Λ_QCD. We also predict that there should be very few three-body decay events containing one soft meson resonance and two energetic mesons or meson resonances. The selection rules are quite different from the soft-pion theorem, since they apply to different kinematical regions. For B⁰→bar D⁰π⁺π^-, the latter predicts that the decay matrix element vanishes in the zero four-momentum limit of π^- instead of π⁺. Since this marked difference from the soft-pion theorem is directly related to the issue of short-distance QCD dominance in two-body B decays, experimental tests of the selection rules will shed light on the strong interaction dynamics of B decay

[en] If one of the recently discovered charmed-strange mesons (D_sJ(2317)) is the 0+ state of cs-bar, the other (D_sJ(2460)) is most likely the 1+ state with j=1/2. They could be produced in e+e- annihilation by fragmentation from cc-bar jets or as decay products of B mesons. If one analyzes the cc-bar jet events and the B decay events separately, one will have a direct test as to whether D_sJ(2460) is the j=1/2 state or not, how much D_sJ(2460) is mixed with the j=3/2 state, and whether the four-quark interpretation is viable

[en] Models of composite weak bosons, the top-condensate model of electroweak interaction and related models we surveyed. Composite weak bosons must be tightly bound with a high compositeness scale in order to generate approximate puge symmetry dynamically. However, naturalness argument suggests that the compositeness scale is low at least in toy models. In the top-condensate model, where a composite Higgs doublet is formed with a very high scale, the prediction of the model is insensitive to details of the model and almost model-independent Actually, the numerical prediction of the t-quark and Higgs boson masses does not test compositeness of the Higgs boson nor condensation of the t-quark field. To illustrate the point, a composite t_R-quark model is discussed which leads to the same numerical prediction as the top-condensate model. However, different constraints an imposed on the structure of the Higgs sector, depending on which particles are composite. The attempt to account the large t-b mass splitting by the high compositeness scale of the top-condensate model is reinterpreted in terms of fine tuning of more than one vacuum expectation value. It is difficult to lower, without a fourth generation, the t-quark mass in the composite particle models in general because the Yukawa coupling of the i-quark to the Higgs boson, _t2/4π = 0.1 for m_t = 200 GeV, is too small for a coupling of a composite particle

[en] If the vector glueball Ο exists in the mass range that theory suggests, its resonant production cross section can be detected in e⁺e^- annihilation only if the decay width is very narrow ((le) a few MeV). Otherwise Ο will be observed only indirectly through its mixing with ψ(prime). We propose a few tests of the Ο-ψ(prime) mixing for future charm factories