Charmless Bc→VVB_{c} \to VV decays in the QCD factorization approach

In this paper, we studied the charmless $B_{c}\to VV$ ($V$ denotes the light ground $\rm SU(3)$ vector meson) decays within the framework of QCD factorization. In the evaluation, two different schemes for regulating the end-point divergence are adopted. One (scheme I) is to use parameterization model, which is usually employed in the QCD factorization approach; the other (scheme II) is based on the infrared finite gluon propagator of Cornwall prescription. It is found that, in the annihilation amplitudes, the end-point divergence appears only in the power-suppressed corrections related to the twist-3 distribution amplitudes of $V$-meson. The strength of annihilation amplitudes evaluated in scheme II is generally larger than the one in scheme I. Numerically, in the decay modes considered in this paper, the CKM-favored $B_{c} \to \rho^{-}\omega, K^{*-}K^{*0}$ decays have the relatively large branching fractions, $\sim {\cal{O}}(10^{-7})$, and hence are likely to be the first observed by the future experiments. In addition, all of the decay modes are dominated by the longitudinal polarization state; numerically, $f_{L}(B_{c} \to VV) \gtrsim 99\%$

Meson and Baryon dispersion relations with Brillouin fermions

We study the dispersion relations of mesons and baryons built from Brillouin quarks on one N_f=2 gauge ensemble provided by QCDSF. For quark masses up to the physical strange quark mass, there is hardly any improvement over the Wilson discretization, if either action is link-smeared and tree-level clover improved. For quark masses in the range of the physical charm quark mass, the Brillouin action still shows a perfect relativistic behavior, while the Wilson action induces severe cut-off effects. As an application we determine the masses of the \Omega_c^0, \Omega_{cc}^+ and \Omega_{ccc}^{++} baryons on that ensemble.Comment: 16 pages, 9 figures, 4 tables; v2: one Reference added, matches published versio

Heavy-Baryon Spectroscopy from Lattice QCD

We use a four-dimensional lattice calculation of the full-QCD (quantum chromodynamics, the non-abliean gauge theory of the strong interactions of quarks and gluons) path integrals needed to determine the masses of the charmed and bottom baryons. In the charm sector, our results are in good agreement with experiment within our systematics, except for the spin-1/2 $\Xi_{cc}$, for which we found the isospin-averaged mass to be $\Xi_{cc}$ to be $3665\pm17\pm14^{+0}_{-78}$ MeV. We predict the mass of the (isospin-averaged) spin-1/2 $\Omega_{cc}$ to be $3763\pm19\pm26^{+13}_{-79}$ {MeV}. In the bottom sector, our results are also in agreement with experimental observations and other lattice calculations within our statistical and systematic errors. In particular, we find the mass of the $\Omega_b$ to be consistent with the recent CDF measurement. We also predict the mass for the as yet unobserved $\Xi^\prime_b$ to be 5955(27) MeV.Comment: Invited talk at Conference of Computational Physics 2009. 3 page

a comparative analysis of CDM in South Africa and China

Both South Africa and China are emergent economies heavily dependent on fossilfuel based energy sources, and the potential to leverage the Clean Development Mechanism (CDM) is significant in both countries. However, experience to date with CDM indicates South Africa has significantly lagged behind China in the uptake of the CDM, accounting for only 0.9% of the worldwide registered annual Certified Emission Reductions (CERs) while China has dominated the market, generating over 54% of the annual worldwide CERs. Thus, an opportunity exists to redefine the role of CDM in South Africa to better incentivise a lower carbon development trajectory. This paper provides a comparative analysis of the CDM experience in China and South Africa in order to identify the underlying drivers and obstacles to CDM in both countries. It is the authors’ objective to analyse the lessons learnt from marketleading China and laggard South Africa to better understand the structures and policies necessary within host CDM countries to unlock the potential of CDM in a post 2012 regime