650 research outputs found

    Resolving a Discrete Ambiguity in the CKM Angle β\beta through Bu,dJ/ψKB_{u,d} \to J/\psi K^\ast and BsJ/ψϕB_s \to J/\psi \phi Decays

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    It is well known that sin(2β)\sin(2\beta), where β\beta is one of the angles of the unitarity triangle of the CKM matrix, can be determined in a theoretically clean way by measuring mixing-induced CP violation in the decay BdJ/ψKSB_d \to J/\psi K_S. Another clean extraction of this CKM angle is provided by the time-dependent angular distribution for the decay products of BdJ/ψ(l+l)K0(π0KS)B_d \to J/\psi(\to l^+l^-) K^{\ast0}(\to \pi^0 K_S), where we have more observables at our disposal than in the case of BdJ/ψKSB_d \to J/\psi K_S, so that in addition to sin(2β)\sin(2\beta) also cos(2β)\cos(2\beta) can be probed in a direct way. Unfortunately a sign ambiguity remains in cos(2β)\cos(2\beta). If it could be resolved, a discrete ambiguity in the extraction of the CKM angle β\beta could be resolved as well, which would allow a more incisive test of the CKM model of CP violation. This note shows that detailed time-dependent studies of Bu,dJ/ψKB_{u,d} \to J/\psi K^{\ast} and BsJ/ψϕB_s \to J/\psi \phi decay processes can determine the sign of cos(2β)\cos(2\beta), thereby removing the corresponding ambiguity in the extraction of the CKM angle β\beta.Comment: 5 pages, LaTeX, no figure

    CP Asymmetries in (Semi-)Inclusive B0 Decays

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    It was recently pointed out that inclusive B^0(t) decays could show CP violation. The totally inclusive asymmetry is expected to be tiny [O(10^{-3})] because of large cancellations among the asymmetries in the charmless, single charm and double charm final states. Enriching particular final state configurations could significantly increase the CP-asymmetry and observability. Such studies can extract fundamental CKM (Cabibbo-Kobayashi-Maskawa) parameters, and (perhaps) even Delta m(B_s). A superb vertex detector could see CP violation with 10^5 (10^6) flavor-tagged B_s (B_d) mesons within the CKM model. Because the effects could be significantly larger due to new physics, they should be searched for in existing or soon available data samples.Comment: RevTex, 20 pages, no figure

    Current Topics in D0 B Physics

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    An overview of selected topics in DO B-Physics is presented, covering relevant detector characteristics, and with emphasis on the most recent results in the Bs, FCNC and rare decay programs.Comment: 4 pages, 3 figures, for the D0 Collaboration, 10th International Conference on B-Physics at Hadron Machines - BEAUTY 2005 - June 20 to 24, 2005 in Assisi, Ital

    Yet another way to measure γ\gamma

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    We show that the CKM phase 2β+γ2 \beta+\gamma can be extracted from measurement of the time dependent rates in the decays Bˉ0D()±M\bar{B}^0 \to D^{(*)\pm} M^\mp and B0D()±MB^0 \to D^{(*)\pm} M^\mp, where M=a0M=a_0, π(1300)\pi(1300), b1b_1, a2a_2, π2\pi_2, ρ3\rho_3. These channels have a large asymmetry between decays of Bˉ0\bar{B}^0 and B0B^0 into the same final state. Even though the branching ratios are small, their sensitivity to γ\gamma can be competitive with decays into D()D^{(*)} and (π,ρ,a1)(\pi,\rho,a_1).Comment: 5 pages, some clarifications and references adde

    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

    Implications of a Low sin(2 beta): A Strategy for Exploring New Flavor Physics

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    We explore the would-be consequences of a low value of the CP-violating phase sin2βψK\sin2\beta_{\psi K}. The importance of a reference triangle obtained from measurements that are independent of BB--Bˉ\bar B and KK--Kˉ\bar K mixing is stressed. It can be used to extract separately potential New Physics contributions to mixing in the BdB_d, BsB_s and KK systems. We discuss several constructions of this triangle, which will be feasible in the near future. The discrete ambiguity is at most two-fold and eventually can be completely removed. Simultaneously, it will be possible to probe for New Physics in loop-dominated rare decays.Comment: 9 pages, 6 figure

    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

    Clean CKM Information from Bd(t) -> D(*)+/- pi-/+

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    It has been known for many years that the Bd(t) -> D(*)+/- {pi-/+, rho-/+, a1-/+} modes may involve observable CP violating effects. This note describes how to determine cleanly the Cabibbo-Kobayashi-Maskawa (CKM) phase phi = -2 beta - gamma = -pi + alpha - beta, even in the presence of possible final state interactions. A discrete ambiguity remains.Comment: 8 pages, revte
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