Measuring the CP Angle \beta in Hadronic b\to s Penguin Decays

Asymmetric e^+e^- colliders running on the \Upsilon(4S) (B factories) will much more readily measure CP-violating asymmetries in the decays of B_d^0 and B^\pm mesons than in the decays of B_s^0 mesons. As such, they will seemingly not be able to probe new phases in Bs-Bs(bar) mixing, i.e. in b\to s transitions. However, by measuring the CP angle \beta via b \to s hadronic penguin decays such as B_d^0 \to \eta'\ks and B_d^0 \to\phi\ks, and comparing its value to that obtained in B_d^0 \to\Psi\ks, it is possible to detect the presence of new physics in the b\to s flavour-changing neutral current. Recent CLEO results are encouraging in this regard. They suggest that the branching ratio of the b\to s penguin decay B_d^0 \to \eta'\ks is anomalously large, about 4 \times 10^{-5}, which will make it much easier to search for new physics in b\to s transitions.Comment: 8 pages, LaTeX, 1 figure (included

b Physics Beyond the Standard Model

I review the signals for New Physics in CP-violating measurements in B and Lambda_b decays. I also discuss ways of identifying this New Physics, should such a signal be found.Comment: 10 pages, LaTeX, 1 figure, ps file included. References adde

Flavour-Changing Neutral Currents and Leptophobic Z' Gauge Bosons

Leptophobic Z' gauge bosons can appear in models with an E_6 gauge symmetry. We show that flavour-changing neutral currents can be generated in some of these models due to the mixing of the ordinary d_R, s_R and b_R quark fields with the exotic h_R. Because the Z' does not couple to charged leptons, the constraints on the flavour-changing couplings U^{Z'}_{db} and U^{Z'}_{sb} are relatively weak. Indeed, B_q--Bbar_q mixing (q=d,s) can be dominated by Z' exchange, which will affect CP-violating rate asymmetries in B decays. Rare hadronic B decays can also be affected, while decays involving charged leptons will be unchanged.Comment: 11 pages, LaTeX, no figure

CP Violation with Heavy Hadrons

I review several topics involving CP violation with heavy hadrons. In particular, I discuss (i) Hyperons: CP violation in the decay $\Lambda^0 \to p \pi^-$, (ii) Charm: indirect CP violation in the D^0 system, both within and beyond the SM, and (iii) Beauty: indirect CP violation in the neutral B-meson system beyond the SM. Talk presented at the 2nd International Conference on Hyperons, Charm and Beauty Hadrons, Montr\'eal, Canada, August 1996.Comment: 12 pages, latex, 1 figure (included

Mixing-Induced CP Violation in the Decay Bd→K0Kˉ0B_d\to K^0 \bar K^0 within the Standard Model

Recently, flavour $SU(3)$ symmetry of strong interactions has been combined with certain dynamical assumptions to derive triangle relations among $B$-meson decay-amplitudes. We show that these relations allow a prediction of the mixing-induced CP asymmetry \acpmi(B_d\to K^0\bar K^0). Contrary to statements made in several previous papers, this asymmetry should be non-vanishing in the Standard Model due to QCD-penguins with internal up- and charm-quark exchanges and could be as large as \order(30\%). The branching ratio BR$(B_d\to K^0\bar K^0)$ is expected to be of \order(10^{-6}). In the future, the results presented in this letter should allow interesting tests of the $SU(3)$ triangle relations and of the Standard Model description of CP violation.Comment: 13 pages (LaTeX) + 4 figures included, Munich Technical University preprint TUM-T31-76/9

Determining the Quark Mixing Matrix From CP-Violating Asymmetries

If the Standard Model explanation of CP violation is correct, then measurements of CP-violating asymmetries in $B$ meson decays can in principle determine the entire quark mixing matrix.Comment: 8 pages (plain TeX), 1 figure (postscript file appended), DAPNIA/SPP 94-06, NSF-PT-94-2, UdeM-LPN-TH-94-18

Corrections to sin(2 beta) from CP asymmetries in B^0 -> (pi^0,rho^0,eta,eta^',omega,phi) K_S decays

Neglecting smaller amplitudes the time-dependent CP asymmetry in penguin-dominated b -> s q \bar q transitions (such as B -> phi K_S) is expected to equal sin(2 beta), an expectation not borne out by the present average experimental data. I compute and discuss the correction due to the smaller amplitudes in the framework of QCD factorization.Comment: 11 pages, 2 figues, LaTe

CP Asymmetry in B_d --> phi K_S: Standard Model Pollution

The difference in the time dependent CP asymmetries between the modes $B --> psi K_S$ and $B --> phi K_S$ is a clean signal for physics beyond the Standard Model. This interpretation could fail if there is a large enhancement of the matrix element of the $b --> u ubar s$ operator between the $B_d$ initial state and the $phi K_S$ final state. We argue against this possibility and propose some experimental tests that could shed light on the situation.Comment: 9 pages, Revte

Exploring CP Violation with B_d -> D K_s Decays

We (re)examine CP violation in the decays B_d -> D K_s, where D represents D^0, D(bar), or one of their excited states. The quantity $\sin^2(2\beta + \gamma)$ can be extracted from the time-dependent rates for $B_d(t) -> {\bar D}^{**0} K_s$ and $B_d(t) -> D^{**0} K_s$, where the $D^{**0}$ decays to $D^{(*)+}\pi^-$. If one considers a non-CP-eigenstate hadronic final state to which both D(bar) and D^0 can decay (e.g. $K^+\pi^-$), then one can obtain two of the angles of the unitarity triangle from measurements of the time-dependent rates for $B_d(t) -> (K^+\pi^-)_{D K_s}$ and $B_d(t) -> (K^-\pi^+)_{D K_s}$. There are no penguin contributions to these decays, so all measurements are theoretically clean.Comment: 15 pages, LaTeX, no figure