1,342 research outputs found
Flavor SU(3) analysis of charmless B meson decays to two pseudoscalar mesons
Global fits to charmless B --> PP decays in the framework of flavor SU(3)
symmetry are updated and improved without reference to the \sin2\beta measured
from the charmonium decay modes. Fit results directly constrain the
(\bar\rho,\bar\eta) vertex of the unitarity triangle, and are used to predict
the branching ratios and CP asymmetries of all decay modes, including those of
the B_s system. Different schemes of SU(3) breaking in decay amplitude sizes
are analyzed. The major breaking effect between strangeness-conserving and
strangeness-changing decays can be accounted for by including a ratio of decay
constants in tree and color-suppressed amplitudes. The possibility of having a
new physics contribution to K \pi decays is also examined from the data fitting
point of view.Comment: 22 pages and 2 figures; some comments and references added; more
references added, version to appear in journa
Search for X(3872) in gamma gamma Fusion and ISR at CLEO
We report on a search for the X(3872) state using 15.1 fb^{-1} of e+ e-
annihilation data taken with the CLEO III detector in the sqrt{s} = 9.46-11.30
GeV region. Separate searches for the production of X(3872) in untagged gamma
gamma fusion and e+ e- annihilation following initial state radiation are made
by taking advantage of the unique correlation of J/psi -> l+ l- in X(3872)
decay into J/psi pi+ pi-. No signals are observed in either case, and 90%
confidence upper limits are established as (2J+1)Gamma_{gammagamma}(X(3872))B(X
-> J/psi pi+ pi-) J/psi pi+ pi-) < 8.3
eV.Comment: 4 pages, 2 figures, to appear in the proceedings of the 1st Meeting
of the APS Topical Group on Hadronic Physics, Fermilab, Oct. 24-26, 200
The 2004 UTfit Collaboration Report on the Status of the Unitarity Triangle in the Standard Model
Using the latest determinations of several theoretical and experimental
parameters, we update the Unitarity Triangle analysis in the Standard Model.
The basic experimental constraints come from the measurements of |V_ub/V_cb|,
Delta M_d, the lower limit on Delta M_s, epsilon_k, and the measurement of the
phase of the B_d - anti B_d mixing amplitude through the time-dependent CP
asymmetry in B^0 to J/psi K^0 decays. In addition, we consider the direct
determination of alpha, gamma, 2 beta + gamma and cos(2 beta) from the
measurements of new CP-violating quantities, recently performed at the B
factories. We also discuss the opportunities offered by improving the precision
of the various physical quantities entering in the determination of the
Unitarity Triangle parameters. The results and the plots presented in this
paper can also be found at http://www.utfit.org, where they are continuously
updated with the newest experimental and theoretical results.Comment: 32 pages, 17 figures. High resolution figures and updates can be
found at http://www.utfit.org v2: misprints correcte
Defining pharmacy and its practice: a conceptual model for an international audience
Background: There is much fragmentation and little consensus in the use of descriptors for the different disciplines that make up the pharmacy sector. Globalization, reprofessionalization and the influx of other disciplines means there is a requirement for a greater degree of standardization. This has not been well addressed in the pharmacy practice research and education literature.
Objectives: To identify and define the various subdisciplines of the pharmacy sector and integrate them into an internationally relevant conceptual model based on narrative synthesis of the literature.
Methods: A literature review was undertaken to understand the fragmentation in dialogue surrounding definitions relating to concepts and practices in the context of the pharmacy sector. From a synthesis of this literature, the need for this model was justified. Key assumptions of the model were identified, and an organic process of development took place with the three authors engaging in a process of sense-making to theorize the model.
Results: The model is “fit for purpose” across multiple countries and includes two components making up the umbrella term “pharmaceutical practice”. The first component is the four conceptual dimensions, which outline the disciplines including social and administrative sciences, community pharmacy, clinical pharmacy and pharmaceutical sciences. The second component of the model describes the “acts of practice”: teaching, research and professional advocacy; service and academic enterprise.
Conclusions: This model aims to expose issues relating to defining pharmacy and its practice and to create dialogue. No model is perfect, but there are implications for what is posited in the areas of policy, education and practice and future research. The main point is the need for increased clarity, or at least beginning the discussion to increase the clarity of definition and consistency of meaning in-and-across the pharmacy sector locally, nationally and internationall
Direct CP Violation, Branching Ratios and Form Factors , in Decays
The and transitions involved in hadronic B decays are
investigated in a phenomenological way through the framework of QCD
factorization. By comparing our results with experimental branching ratios from
the BELLE, BABAR and CLEO Collaborations for all the B decays including either
a pion or a kaon, we propose boundaries for the transition form factors and depending on the CKM matrix element parameters and
. From this analysis, the form factors required to reproduce the
experimental data for branching ratios are and
. We calculate the direct CP violating asymmetry
parameter, , for and decays, in the case where mixing effects are taken into
account. Based on these results, we find that the direct CP asymmetry for
, ,
, and , reaches its maximum when the invariant mass is
in the vicinity of the meson mass. The inclusion of
mixing provides an opportunity to erase, without ambiguity, the phase
uncertainty mod in the determination of the CKM angles in case
of and in case of .Comment: 74 pages, 15 figures, 8 tables. A few misprints corrected, two
references adde
APC-β-catenin-TCF signaling silences the intestinal guanylin-GUCY2C tumor suppressor axis.
Sporadic colorectal cancer initiates with mutations in APC or its degradation target β-catenin, producing TCF-dependent nuclear transcription driving tumorigenesis. The intestinal epithelial receptor, GUCY2C, with its canonical paracrine hormone guanylin, regulates homeostatic signaling along the crypt-surface axis opposing tumorigenesis. Here, we reveal that expression of the guanylin hormone, but not the GUCY2C receptor, is lost at the earliest stages of transformation in APC-dependent tumors in humans and mice. Hormone loss, which silences GUCY2C signaling, reflects transcriptional repression mediated by mutant APC-β-catenin-TCF programs in the nucleus. These studies support a pathophysiological model of intestinal tumorigenesis in which mutant APC-β-catenin-TCF transcriptional regulation eliminates guanylin expression at tumor initiation, silencing GUCY2C signaling which, in turn, dysregulates intestinal homeostatic mechanisms contributing to tumor progression. They expand the mechanistic paradigm for colorectal cancer from a disease of irreversible mutations in APC and β-catenin to one of guanylin hormone loss whose replacement, and reconstitution of GUCY2C signaling, could prevent tumorigenesis
Heavy Quark Spectroscopy -- Theory Overview
Some recent discoveries in the spectroscopy of hadrons containing heavy
quarks, and some of their theoretical interpretations, are reviewed.Comment: 13 pages, 6 figures. Presented at Second Meeting of APS Topical Group
on Hadron Physics, Nashville, TN, 22-24. Proceedings to be published by
Journal of Physics (UK), Conference Series. Uses jpconf.cls, jpconf11.clo.
Some corrections; references update
Non-factorizable Contributions to Decays
We investigate to what extent the experimental information on
branching fractions and CP asymmetries can be used to better understand the QCD
dynamics in these decays. For this purpose we decompose the independent isospin
amplitudes into factorizable and non-factorizable contributions. The former can
be estimated within the framework of QCD factorization for exclusive
decays. The latter vanish in the heavy-quark limit, , and are
treated as unknown hadronic parameters. We discuss at some length in which way
the non-factorizable contributions are treated in different theoretical and
phenomenological frameworks. We point out the potential differences between the
phenomenological treatment of power-corrections in the ``BBNS approach'', and
the appearance of power -suppressed operators in soft-collinear effective
theory (SCET). On that basis we define a handful of different (but generic)
scenarios where the non-factorizable part of isospin amplitudes is parametrized
in terms of three or four unknowns, which can be constrained by data. We also
give some short discussion on the implications of our analysis for decays. In particular, since non-factorizable QCD effects in
may be large, we cannot exclude sizeable non-factorizable effects, which
violate flavour symmetry, or even isospin symmetry (via long-distance
QED effects). This may help to explain certain puzzles in connection with
isospin-violating observables in decays.Comment: published version, minor correction
Can there be any new physics in b -> d penguins
We analyze the possibility of observing new physics effects in the
penguin amplitudes. For this purpose, we consider the decay mode , which has only penguin contributions. Using the QCD
factorization approach, we find very tiny CP violating effects in the standard
model for this process. Furthermore, we show that the minimal supersymmetric
standard model with mass insertion and R-parity violating supersymmetric
model can provide substantial CP violation effects. Observation of sizable CP
violation in this mode would be a clear signal of new physics.Comment: Published versio
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