A Relativistic Description of Hadronic Decays of the Meson π1\pi_{1}

The subject of this work is the analysis of hadronic decays of the exotic meson $\pi_{1}$ in a fully relativistic formalism, and comparison with the nonrelativistic results. The relativistic spin wave functions of mesons and hybrids are constructed based on unitary representations of the Lorentz group. The radial wave functions are obtained from phenomenological considerations of the mass operator. We find that the decay channels $\pi b_{1}$ and $\pi f_{1}$ are favored, in agreement with the results obtained using other models, thus indicating some model independence of the S+P selection rules.Comment: 6 pages. Prepared for Hadron '03: 10th International Conference on Hadron Spectroscopy, Aschaffenburg, Germany, 31 Aug - 6 Sep 2003. This article may be found at http://proceedings.aip.org/proceedings/confproceed/717.js

The cosmic jerk parameter in f(R) gravity

We derive the expression for the jerk parameter in $f(R)$ gravity. We use the Palatini variational principle and the field equations in the Einstein conformal gauge. For the particular case $f(R)=R-\frac{\alpha^2}{3R}$, the predicted value of the jerk parameter agrees with the SNLS SNIa and X-ray galaxy cluster distance data but does not with the SNIa gold sample data.Comment: 8 pages; published versio