
Johan Bijnens, Ilaria Jemos
Vector Formfactors in Hard Pion Chiral Perturbation Theory
Abstract
We use threeflavour hard pion Chiral Perturbation Theory (HPChPT) in both
the heavy meson and a relativistic formulation to calculate the chiral
logarithms $m^2\log(m^2/\mu^2)$ contributing to the formfactors of the
$B_{(s)}\rightarrow \pi,K,\eta$ and $D_{(s)}\rightarrow \pi,K,\eta$
transitions at momentum transfer $q^2$ away from the endpoint
$q^2_\mathrm{max}=(m_Bm_M)^2$. We compare our results with CLEO $D\to\pi$
and $D\to K$ data. We also calculate the IsgurWise function of the
$B_{(s)}\rightarrow D_{(s)}$ semileptonic decay away from the endpoint and
the chiral logarithms for the pion and kaon electromagnetic formfactor.
In twoflavour HPChPT we calculate the chiral logarithms for the pion
vector and the scalar formfactors at $s\gg m_\pi^2$. This allows us to
test hard pion ChPT using the existing twoloop calculations for these
quantities.
LU TP 1027
