CP Violation in B -> pi K Decays

I briefly review CP violation in the B system, concentrating on B -> pi K decays. I discuss how to deal with electroweak-penguin contributions to these decays using flavour SU(3). With these, I show that the entire unitarity triangle can be extracted from measurements of B -> pi K decays. Finally, I examine the signals for new physics in these decays and the possibilities for measuring them.Comment: 8 pages, no figure, plain latex, To be published in the proceedings of MRST 2004: From Quarks to Cosmology, Concordia University, Montreal, May 2004, references adde

Diagrammatic Analysis of Charmless Three-Body B Decays

We express the amplitudes for charmless three-body B decays in terms of diagrams. In addition, we show how to use Dalitz-plot analyses to obtain decay amplitudes which are symmetric or antisymmetric under the exchange of two of the final-state particles. When annihilation-type diagrams are neglected, as in two-body decays, many of the exact, purely isospin-based results are modified, leading to new tests of the standard model (SM). Some of the tests can be performed now, and we find that present data agree with the predictions of the SM. Furthermore, contrary to what was thought previously, it is possible to cleanly extract weak-phase information from three-body decays, and we discuss methods for B -> K pi pi, K K Kbar, K Kbar pi and pi pi pi.Comment: 30 pages, 10 figures, reference updated, sentences added regarding indirect CP violation and CP of the final state. Significant text added describing how to obtain symmetric/antisymmetric decay amplitudes, results of the comparison of the predictions of the SM with present data for several decays, and the momentum dependence of the diagram

Extraction of the CP-violating phase γ\gamma using B→KππB \to K \pi \pi and B→KKKˉB \to K K {\bar K} decays

Using the B{\sc a}B{\sc ar}\ measurements of the Dalitz plots for $B^0 \to K^+\pi^0\pi^-$, $B^0 \to K^0\pi^+\pi^-$, $B^+ \to K^+\pi^+\pi^-$, $B^0 \to K^+ K^0 K^-$, and $B^0 \to K^0 K^0 {\bar K}^0$ decays, we demonstrate that it is possible to cleanly extract the weak phase $\gamma$. We find four possible solutions. Three of these -- $32^\circ$, $259^\circ$, and $315^\circ$ -- are in disagreement with the SM, while one -- $77^\circ$ -- is consistent with the SM. An advantage of this Dalitz-plot method is that one can obtain many independent measurements of $\gamma$, thereby reducing its statistical error. An accurate determination of the errors, however, requires detailed knowledge of the data.Comment: 9 pages, 2 figures, version accepted for publication in Physics Letters

Extracting alpha from B0(d) --> K0 anti-K0 Decays

We propose a new method for obtaining the CP phase alpha, based on measurements of B0(d) --> K0 anti-K0, along with theoretical input. Due to the similarities of QCD factorization (QCDf) and perturbative QCD (pQCD), this input is basically the same for each of these models. Although the theoretical error is large at present, many of the contributing quantities will be better known in the future, leading to a smaller error. One outstanding question is the extent to which the precision on quark masses, especially m_c/m_b, can be improved. If one assumes that new physics is not present, the method can be used to predict the values of CP asymmetries in B0(d) --> K0 anti-K0: 0.02 <= A_{dir}^2 + A_{mix}^2 <= 0.125. A result outside this range would signal the existence of long-distance effects beyond those included in models of nonleptonic decays based on factorization (such as QCDf and pQCD), or the presence of new physics.Comment: 5 pages, To appear in PR

Sujets variés concernant les désintégrations hadroniques des mésons B

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Hadronic B Decays: A General Approach

In this paper, we propose a general approach for describing hadronic B decays. Using this method, all amplitudes for such decays can be expressed in terms of contractions, though the matrix elements are not evaluated. Many years ago, Buras and Silvestrini proposed a similar approach. However, our technique goes beyond theirs in several ways. First, we include recent theoretical and experimental developments which indicate which contractions are negligible, and which are expected to be smaller than others. Second, we show that all B-decay diagrams can be simply expressed in terms of contractions. This constitutes a formal proof that the diagrammatic method is rigourous. Third, we show that one reproduces the relations between tree and electroweak-penguin diagrams described by Neubert and Rosner, and by Gronau, Pirjol and Yan. Fourth, although the previous results hold to all orders in alpha_s, we show that it is also possible to work order-by-order in this approach. In this way it is possible to make a connection with the matrix-element evaluation methods of QCD factorization (QCDfac) and perturbative QCD (pQCD). Finally, using the contractions approach, we re-evaluate the question of whether there is a ``B -> pi K puzzle.'' At O(alpha_s^0), we find that the diagram ratio |C'/T| is about 0.17, a factor of 10 too small to explain all the B -> pi K data. Both QCDfac and pQCD find that, at O(\alpha_s^1), the value of |C'/T'| may be raised to only about 2-3 times its lowest-order value. We therefore conclude that, assuming the effect is not a statistical fluctuation, it is likely that the value of |C'/T'| is similar to its O(\alpha_s^0) result, and that there really is a B -> pi K puzzle.Comment: 33 pages, plain latex, 10 figures (included