302 research outputs found

    Heavy Baryon Production and Decay

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    The branching ratio B(Lambda_c -> p K- pi+) normalizes the production and decay of charmed and bottom baryons. At present, this crucial branching ratio is extracted dominantly from B.bar -> baryons analyses. This note questions several of the underlying assumptions and predicts sizable B.bar -> D(*) N N'.bar X transitions, which were traditionally neglected. It predicts B(Lambda_c -> p K- pi+) to be significantly larger (0.07 +/- 0.02) than the world average. Some consequences are briefly mentioned. Several techniques to measure B(Lambda_c -> p K- pi+) are outlined with existing or soon available data samples. By equating two recent CLEO results, an appendix obtains B(D0 -> K- pi+)= 0.035 +/- 0.002, which is somewhat smaller than the current world average.Comment: 27 pages, 4 eps figures, revte

    Enhanced CP Violation with BKD0(D0)B\to K D^0 (\overline D^0) Modes and Extraction of the CKM Angle gamma

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    The Gronau-London-Wyler (GLW) method extracts the CKM angle γ\gamma by measuring B±B^\pm decay rates involving D0/D0D^0/\overline D^0 mesons. Since that method necessitates the interference between two amplitudes that are significantly different in magnitude, the resulting asymmetries tend to be small. CP violation can be greatly enhanced for decays to final states that are common to both D^0 and D0\overline D^0 and that are not CP eigenstates. In particular, large asymmetries are possible for final states f such that D0fD^0\to f is doubly Cabibbo suppressed while D0f\overline D^0\to f is Cabibbo allowed. The measurement of interference effects in two such modes allows the extraction of γ\gamma without prior knowledge of Br(BKD0)Br(B^-\to K^- \overline D^0), which may be difficult to determine due to backgrounds.Comment: 12 pages, LaTeX, no figure

    Theoretical correction to the neutral B0B^0 meson asymmetry

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    Certain types of asymmetries in neutral meson physics have not been treated properly, ignoring the difference of normalization factors with an assumption of the equality of total decay width. Since the corrected asymmetries in B0B^0 meson are different from known asymmetries by a shift in the first order of CP- and CPT-violation parameters, experimental data should be analyzed with the consideration of this effect as in K0K^0 meson physics.Comment: 7 page

    Extracting Weak Phase Information from B -> V_1 V_2 Decays

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    We describe a new method for extracting weak, CP-violating phase information, with no hadronic uncertainties, from an angular analysis of B -> V_1 V_2 decays, where V_1 and V_2 are vector mesons. The quantity sin2(2β+γ)\sin^2 (2\beta + \gamma) can be cleanly obtained from the study of decays such as B_d^0(t) -> D^{*\pm} \rho^\mp, D^{*\pm} a_1^{\mp}, D^{*0} K^{*0}, etc. Similarly, one can use B_s^0(t) -> D_s^{*\pm} K^{*\mp} to extract sin2γ\sin^2 \gamma. There are no penguin contributions to these decays. It is possible that sin2(2β+γ)\sin^2 (2\beta + \gamma) will be the second function of CP phases, after sin2β\sin 2\beta, to be measured at B-factories.Comment: 4 pages, RevTeX, no figure

    Improved Methods for Observing CP Violation in B+/- --> K+/- D0 and Measuring the CKM Phase gamma

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    Various methods are discussed for obtaining the CKM angle gamma through the interference of the charged B-meson decay channels B- -> K- D0 and B- -> K- D0-bar where the D0 and D0-bar decay to common final states. It is found that choosing final states which are not CP eigenstates can lead to large direct CP violation which can give significant bounds on gamma without any theoretical assumptions. If two or more modes are studied, gamma may be extracted with a precision on the order of +/-15 degrees given about 10^8 B-mesons. We also discuss the case of three body decays of the D0 where additional information may be obtained from the distribution of the D0 decay products and consider the impact of D-D-bar oscillations.Comment: 51 pages 8 figures, typo in equation 33 correcte

    CP Violation and Lifetime Differences of Neutral B Mesons from Correlated B^0-B^0bar Pairs

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    We present a technique to determine the CP violating phases, as well as, the lifetime differences of the mass eigenstates for both BdB_d and BsB_s, by considering correlated BBˉB\bar{B} pairs produced at the Υ\Upsilon resonances. We do not require a detailed time dependent study, but only partial time integrated rates, with the tag time, either preceding or following the decay of the other BB meson to a final state f. f may be a CP eigenstate or a non-CP eigenstate.Comment: 11 Pages Revte

    Bose-Einstein Correlations for Mixed Neutral Mesons

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    Correlations are shown to arise in nonidentical mixed-particle pairs like KoKˉoK^o \bar K^o when observed in identical decay modes like KSKSK_S K_S in multiparticle final states containing many partial waves. No enhancement is found in any single partial wave and all partial wave analyses of the s-wave threshold resonance aoa_o and fof_o should give the same results for all decay modes. In CP violation experiments where BoBˉoB^o - \bar B^o pairs are inclusively produced and correlated decays into ψKS\psi K_S and leptonic modes are observed, the CP-violating lepton asymmetry is enhanced by a factor of two in the kinematic region where Bose enhancement occurs.Comment: 11 page

    Framework for Identification of Neutral B Mesons

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    We introduce a method for the study of CP-violating asymmetries in tagged states of neutral BB mesons with arbitrary coherence properties. A set of time-dependent measurements is identified which completely specifies the density matrix of the initial state in a two-component space with basis vectors B0B^0 and B0\overline B^0, and permits a determination of phases in the Cabibbo-Kobayashi-Maskawa matrix. For a given tagging configuration, the measurement of decays both to flavor eigenstates and to CP eigenstates provides the necessary information.Comment: Submitted to Phys. Rev. Letters. 8 pages, LaTeX, Technion-PH-93-31 / EFI 93-3

    CP violation and CKM phases from angular distributions for BsB_s decays into admixtures of CP eigenstates

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    We investigate the time-evolutions of angular distributions for BsB_s decays into final states that are admixtures of CP-even and CP-odd configurations. A sizable lifetime difference between the BsB_s mass eigenstates allows a probe of CP violation in time-dependent untagged angular distributions. Interference effects between different final state configurations of BsDs+DsB_s\to D^{*+}_s D^{*-}_s, J/ψϕJ/\psi \phi determine the Wolfenstein parameter η\eta from untagged data samples, or -- if one uses Vub/Vcb|V_{ub}|/|V_{cb}| as an additional input -- the notoriously difficult to measure CKM angle γ\gamma. Another determination of γ\gamma is possible by using isospin symmetry of strong interactions to relate untagged data samples of BsK+KB_s\to K^{\ast+} K^{\ast-} and BsK0K0B_s\to K^{\ast0} \overline{K^{\ast0}}. We note that the untagged angular distribution for Bsρ0ϕB_s\to\rho^0 \phi provides interesting information about electroweak penguins.Comment: 19 pages, LaTeX, no figure
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