Tests of Factorization and SU(3) Relations in B Decays into Heavy-Light Final States

Using data from the B factories and the Tevatron, we perform tests of how well non-leptonic B decays of the kind B -> D^{(*)}_{(s)} P, where P is a pion or kaon, are described within the factorization framework. We find that factorization works well - as is theoretically expected - for color-allowed, tree-diagram-like topologies. Moreover, also exchange topologies, which have a non-factorizable character, do not show any anomalous behavior. We discuss also isospin triangles between the B -> D^{(*)} pi decay amplitudes, and determine the corresponding amplitudes in the complex plane, which show a significant enhancement of the color-suppressed tree contribution with respect to the factorization picture. Using data for B -> D^{(*)} K decays, we determine SU(3)-breaking effects and cannot resolve any non-factorizable SU(3)-breaking corrections larger than \sim 5%. In view of these results, we point out that a comparison between the \bar B^0_d -> D^+\pi^- and \bar B^0_s -> D_s^+\pi^- decays offers an interesting new determination of f_d/f_s. Using CDF data, we obtain the most precise value of this ratio at CDF, and discuss the prospects for a corresponding measurement at LHCb.Comment: 12 pages, 6 figures, matches published version in Physical Review

Towards Automatic Analytic Evaluation of Diagrams with Masses

A method to calculate two-loop self-energy diagrams of the Standard Model is demonstrated. A direct physical application is the calculation of the two-loop electroweak contribution to the anomalous magnetic moment of the muon ${{1/2}(g-2)}_{\mu}$. Presently, we confine ourselves to a ``toy'' model with only $\mu$, $\gamma$ and a heavy neutral scalar particle (Higgs). The algorithm is implemented as a FORM-based program package. For generating and automatically evaluating any number of two-loop self-energy diagrams, a special C-program has been written. This program creates the initial FORM-expression for every diagram generated by QGRAF, executes the corresponding subroutines and sums up the final results.Comment: LaTeX, 20 pages, 7 eps-figures included; extended version of talk given at AIHEN96, Lausanne, 1-6 Sept. 1996; detailed description of C-program is given; accepted for publication in Comp.Phys.Com

Amplification of High Harmonics Using Weak Perturbative High Frequency Radiation

The mechanism underlying the substantial amplification of the high-order harmonics q \pm 2K (K integer) upon the addition of a weak seed XUV field of harmonic frequency q\omega to a strong IR field of frequency \omega is analyzed in the framework of the quantum-mechanical Floquet formalism and the semiclassical re-collision model. According to the Floquet analysis, the high-frequency field induces transitions between several Floquet states and leads to the appearance of new dipole cross terms. The semiclassical re-collision model suggests that the origin of the enhancement lies in the time-dependent modulation of the ground electronic state induced by the XUV field.Comment: 8 pages, 2 figure

Effects of R-parity violation on direct CP violation in B decays and extraction of γ\gamma

In the standard model, direct CP-violating asymmetries for $B^\pm \to \pi^\pm K$ are roughly 2% based on perturbative calculation. Rescattering effects might enhance it to at most (20-25)%. We show that lepton-number-violating couplings in supersymmetric models without R-parity are capable of inducing as large as 100% CP asymmetry in this channel. Such effects drastically modify the allowed range of the CKM parameter $\gamma$ arising from the combinations of the observed charged and neutral B decays in the $\pi K$ modes. With a multichannel analysis in B decays, one can either discover this exciting new physics, or significantly improve the existing constraints on it.Comment: Latex, 5 pages; minor changes, to appear in Phys Rev Let

Adiabatic theorem for non-hermitian time-dependent open systems

In the conventional quantum mechanics (i.e., hermitian QM) the adia- batic theorem for systems subjected to time periodic fields holds only for bound systems and not for open ones (where ionization and dissociation take place) [D. W. Hone, R. Ketzmerik, and W. Kohn, Phys. Rev. A 56, 4045 (1997)]. Here with the help of the (t,t') formalism combined with the complex scaling method we derive an adiabatic theorem for open systems and provide an analytical criteria for the validity of the adiabatic limit. The use of the complex scaling transformation plays a key role in our derivation. As a numerical example we apply the adiabatic theorem we derived to a 1D model Hamiltonian of Xe atom which interacts with strong, monochromatic sine-square laser pulses. We show that the gener- ation of odd-order harmonics and the absence of hyper-Raman lines, even when the pulses are extremely short, can be explained with the help of the adiabatic theorem we derived

A Critical Study of B Decays to Light Pseudoscalar

Motivated by the large branching ratios observed for the process $B\to\eta^{\prime}K$, we examine critically all the ingredients that go into estimates of B decays into two light pseudoscalars. Within factorization approximation, we examine several assumptions on the input parameters that could have a strong bearing on the predictions. Among these are (i) the QCD scale $\mu$ (ii) value of the form factors (iii) value of the light quark masses, and in particular $m_s$ (iv) the value $\xi=1/N_c$, (v) charm content of $\eta^{\prime}$. It is possible to account for all the data without invoking new physics, though future experiments will provide tighter constraints on the parameter space. We fin that CP violating asymmetries are in the observable range for some modes.Comment: 29 pages(Latex), 17 figures, a few changes have been made, version to appear in Phys.Rev.

Determining the Weak Phase γ\gamma From Charged BB Decays

A quadrangle relation is shown to be satisfied by the amplitudes for $B^+ \to \pi^0 K^+,~\pi^+ K^0,~\eta K^+$, and $\eta' K^+$. By comparison with the corresponding relation satisfied by $B^-$ decay amplitudes, it is shown that the relative phases of all the amplitudes can be determined up to discrete ambiguities. Making use of an SU(3) relation between amplitudes contributing to the above decays and those contributing to $B^{\pm} \to \pi^{\pm} \pi^0$, it is then shown that one can determine the weak phase $\gamma \equiv {\rm Arg} (V_{ub}^* V_{cb}/V_{us}^* V_{cs})$, where $V$ is the Cabibbo-Kobayashi-Maskawa matrix describing the charge-changing weak interactions between the quarks $(u,c,t)$ and $(d,s,b)$.Comment: 16 pages, latex, 7 uuencoded figure

Constraints on the phase γ\gamma and new physics from B→KπB\to K\pi Decays

Recent results from CLEO on $B\to K\pi$ indicate that the phase $\gamma$ may be substantially different from that obtained from other fit to the KM matrix elements in the Standard Model. We show that $\gamma$ extracted using $B\to K\pi, \pi\pi$ is sensitive to new physics occurring at loop level. It provides a powerful method to probe new physics in electroweak penguin interactions. Using effects due to anomalous gauge couplings as an example, we show that within the allowed ranges for these couplings information about $\gamma$ obtained from $B\to K \pi, \pi\pi$ can be very different from the Standard Model prediction.Comment: Revised version with analysis done using new data from CLEO. RevTex, 11 Pages with two figure

Long-range two-body final-state interactions and direct CP asymmetry in {B}^{+}\to{\pi}^{+} {K}^{0} decay

We present a calculation of the direct CP asymmetry, $A_{CP}^{dir}$, for the process $B^+ \to \pi^+ K^0$ including the effects of long-range inelastic final-state interactions (FSI). We admit three channels in our calculation: $B^+ \to (\pi^+ K^0), (\eta K^+)$, and $(D_s^+ \bar{D}^0)$. The strong scattering is described in terms of Pomeron and Regge exchanges. We find that the direct CP asymmetry is enhanced by a factor of $\sim 3$ as a result of FSI, but remains well short of the claims of (10 - 20)% in recent literature. A critical assessment of papers claiming large CP asymmetries is also presented.Comment: 21 pages, latex, no figures. Added the charge-exchange channel {B}^{+}\to {\pi}^{0} {K}^{+}. Expanded the discussion section. To be published in Phys. Rev.

Exploring CP Violation through Correlations in B --> pi K, B_d --> pi^+pi^-, B_s --> K^+K^- Observable Space

We investigate allowed regions in observable space of B --> pi K, B_d --> pi^+pi^- and B_s --> K^+K^- decays, characterizing these modes in the Standard Model. After a discussion of a new kind of contour plots for the $B\to\pi K$ system, we focus on the mixing- induced and direct CP asymmetries of the decays B_d --> pi^+pi^- and B_s--> K^+K^-. Using experimental information on the CP-averaged B_d --> pi^{+/-}K^{+/-} and B_d --> pi^+pi^- branching ratios, the relevant hadronic penguin parameters can be constrained,implying certain allowed regions in observable space. In the case of B_d --> pi^+pi^-, an interesting situation arises now in view of the recent B-factory measurements of CP violation in this channel, allowing us to obtain new constraints on the CKM angle gamma as a function of the B^0_d--\bar{B^0_d} mixing phase phi_d=2beta, which is fixed through A_{CP}^{mix}(B_d --> J/psi K_S) up to a twofold ambiguity. If we assume that A_{CP}^{mix}(B_d --> pi^+pi^-) is positive, as indicated by recent Belle data, and that phi_d is in agreement with the ``indirect'' fits of the unitarity triangle, also the corresponding values for gamma around 60 degrees can be accommodated. On the other hand, for the second solution of phi_d, we obtain a gap around gamma ~ 60 degrees. The allowed region in the space of A_{CP}^{mix}(B_s --> K^+K^-) and A_{CP}^{dir}(B_s --> K^+K^-) is very constrained in the Standard Model, thereby providing a narrow target range for run II of the Tevatron and the experiments of the LHC era.Comment: 34 pages, LaTeX, 12 figures. More detailed introduction and a few Comments added, conclusions unchanged. To appear in Phys. Rev.