1,454 research outputs found

    On a clean determination of ϕ2\phi_2

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    We point out that time dependent study of four decay modes B^0(t)\to \Dbar K_S, B0(t)DKSB^0(t)\to D K_S \Bbar^0(t)\to \Dbar K_S, and \Bbar^0(t)\to D K_S allows us to measure sin(ϕ1ϕ2)\sin(\phi_1-\phi_2) - contrary to previously obtained result that it measures sin(2ϕ1+ϕ3)\sin(2\phi_1+\phi_3). The time dependent study of Bs0(t)Ds±KB_s^0(t)\to D^\pm_sK^\mp, and the study of B^-\to K^-(D,\Dbar)\to K^-f decay where DfD\to f is a doubly Cabibbo suppressed decay yield information on ϕ3\phi_3, as previusly expected.Comment: 6 pages 2 figure

    Summary of Weak Decays, CKM and CP Violation Session Penguins

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    In our subgroup, we focused on penguin physics from various different angles. Our discussions included: (1) A method to extract one of the angles of the unitarity triangle ϕ2\phi_2; (2) Methods to extract ϕ3\phi_3 from BKπB\to K\pi decays; (3) Effects of non-minimal SUSY on B and K decays; (4) Understnding large branching ratios for Bη+K(K)B\to \eta'+K(K^*) decays; (5) New calculation for hadronic matrix elements which are needed to compute ϵ/ϵ\epsilon'/\epsilon.Comment: To appear in the proceedings for WIN99 Cape Tow

    Comments on CPT tests

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    What do we know about CPT symmetry? We conclude that the direcrt measurement of CPT violation leads to a result that CPT violation force is limited to about 30% of CP violating forces. The best test of CPT symmetry is to see if theoretical prediction for the phase of eta_{+-} and eta_{00} agree with experiments. We discuss uncertainties associated with this prediction, and how to improve it. A new test of CPT is also discussed.Comment: Talk presented at KEK-Tanash workshop on K decay

    Searching for T,CP,CPT,and \Delta S = \Delta Q rule violations in the neutral K meson system - a guide

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    It is known that the existing experimental limit forCPT CPT violation is rather poor; the 10 \% level at best. The \DSDQ rule is tested only up to 2 \%. In this note, we discuss the possibility of measuring T,CP,CPT T, CP, CPT and \DSDQ rule violations in the neutral K K meson system. It is shown that not all the symmetry breaking parameters can be determined at a symmetric ϕ \phi factory. Experiments with K0 K^0 and Kˉ0 \bar{K}^0 beams are needed to test all the symmetries.Comment: RevTex, 43 pages, DPNU 93-0

    A new method of determining Vub|V_{ub}| by the processes Bˉρlνˉ\bar{B} \to \rho l \bar{\nu} and \bar{B} \to K^* l \lbar

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    The differential decay width of the process Bˉρlνˉ\bar{B} \rightarrow \rho l \bar{\nu} is related to that of the process \bar{B} \rightarrow K^* l \lbar by using SU(3)SU(3)-flavor symmetry and the heavy quark symmetry. The ratio of the Kobayashi-Maskawa matrix elements is obtained in the zero recoil limit of ρ\rho and KK^*, allowing a determination of Vub|V_{ub}|.Comment: Latex file 9 pag

    Calculation of Magnetic Penguin Amplitudes in B -> phi K Decays using PQCD Approach

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    New physics contributions to B decays often arise through chromo-magnetic penguin operators. To look for new physics effects in B decays, it is useful to be able to estimate the hadronic matrix elements for the chromo-magnetic operator. We compute this contribution to B ->phi K decays using PQCD methods. It is shown that, if the Wilson coefficient of the new physics is same order of magnitude as that of the Standard Model, this operator gives a non-negligible contribution compared to that of the Standard Model (about 30%). We also investigate the value of q^2, which is the momentum transferred by the gluon in the chromo-magnetic penguin operator. We find that the expectation value is approximately M^2_B/4, in agreement with a naive guess. This result, however, is very sensitive to the scale dependence of the Wilson coefficient. We also show that the matrix element for the chromo-magnetic penguin operator is independent of the choice of energy scale to a very good approximation.Comment: 15 pages, 3 figures, LaTeX with the PTP style, minor changes of typo

    How well can we predict CP asymmetry in BππB\to \pi\pi, KπK\pi decays?

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    Using the perturbative QCD amplitudes for BππB\to \pi\pi and BKπB\to K\pi, we have performed an extensive study of the parameter space where the theoretical predictions for the branching ratios are consistent with recent experimental data. From this allowed range of parameter space, we predict the mixing induced CP asymmetry for Bπ+πB \to \pi^+\pi^- with about 11% uncertainty and the other CP asymmetries for BππB\to \pi\pi, KπK\pi with 40% ~ 47% uncertainty. These errors are expected to be reduced as we restrict the parameter space by studying other decay modes and by further improvements in the experimental data.Comment: 15 pages, 4 figures, 2 table

    CP Violation and Nonleptonic B-meson Decays

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    We discuss the perturbative QCD approach for exclusive non-leptonic two body B-meson decays. We briefly review its ingredients and some important theoretical issues related to the factorization approach. PQCD results are compatible with present experimental data for the charmless B-meson decays. We predict the possibility of large direct CP violation effects in B0π+πB^0 \to \pi^{+}\pi^{-} (23±7(23\pm7 %) and B0K+πB^0\to K^{+}\pi^{-} (17±5(-17\pm5%). For charmed decay BD()πB \to D^{(*)}\pi, we get large non-factorizable contributions for Color-suppressed decays and obtain a2/a10.40.5|a_2/a_1|\sim 0.4-0.5 and Arg(a2/a1)42oArg(a_2/a_1)\sim -42^{o}. In the last section we investigate the method to extract the weak phases ϕ2\phi_2 from BππB \to \pi\pi decay and ϕ3\phi_3 from KπK\pi modes. From BaBar measurement of CP asymmetry for the π+π\pi^{+}\pi^{-} decay, the prefered CKM weak phases are: ϕ1=(24±2)o\phi_1=(24\pm2)^{o}, ϕ2=(78±22)o\phi_2=(78\pm 22)^{o} and ϕ3=(78±22)o\phi_3=(78\pm 22)^{o}.Comment: Invited talk at the Workshop on the CKM Unitarity Triangle, IPPP Durham, April 2003 (eConf C0304052). 6 pages LaTeX, 2 eps figures and 3 tables. Correct typos and add references. Final version of the workshop proceeding

    Is Super-BB Sufficiently Superb? -- On the Motivation for a Super-BB Factory

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    Despite the great success of the Υ(4S)\Upsilon (4S) BB factories at KEK and SLAC and the guaranteed addition of high sensitivity measurements on beauty decays to be performed at the Tevatron and LHC, a strong case can be made for an e+ee^+e^- Super-BB factory yielding data samples of order 101010^{10} BBˉB \bar B pairs as a necessity rather than luxury. It has to be justified through its ability to not only establish deviations from the Standard Model, but also diagnose and interpret those in terms of specific features of the New Dynamics. The role to be played by a Super-BB factory is thus analogous {\em and even in parallel} to that of a linear collider. The latter's goal is to provide more detailed information on previously discovered New Physics involved in the electroweak phase transition. Likewise a Super-BB factory would provide precision probes for analyzing whether such New Dynamics has an impact on heavy flavour dynamics -- a need particularly manifest if the New Physics is housed under the `big tent' of SUSY. The huge statistics of a Super-BB factory and the comprehensive body of accurate measurements uniquely possible there would be harnessed in several classes of studies, among them more precise extractions of V(ub)/V(cb)V(ub)/V(cb) and V(td)/V(ts)V(td)/V(ts), more detailed analyses of BγXs,d,l+lXB\to \gamma X_{s,d}, l^+l^-X and novel data on Bτν,τνD,ννˉXB\to \tau \nu, \tau \nu D, \nu \bar \nu X and maybe even on Υ(5S)BsBˉs\Upsilon (5S) \to B_s \bar B_s -- all in addition to a host of CP asymmetries.Comment: Based on talks given at the 5th Workshop on a Higher Luminosity B Factory, Sept. 24 - 26, 2003, Izu, Japan; LATEX, 28 pages, no figure

    Getting at the CP Angles

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    In anticipation for intensive experimental effort on B physics, theorists have introduced many ingenious ways to measure properties of the unitarity triangle. We review some of these methods. We will be critical in the hope that, if there is any defect in them, it can be remedied either theoretically or experimentally.Comment: Sprocl 15 pages. Talk given (by A.I.S.) at the 7th International Symposium on Heavy Flavor Physics, Santa Barbara, July 7 - 11, 1997 (to appear in the proceedings
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