Speaker
Description
We present preliminary results for form factors and structure functions
of some of spin-$0$, spin-$1/2$ and spin-$1$ heavy quarkonia and triply-heavy
baryons in heavy flavor QCD. Using renormalization group procedure for
effective particles (RGPEP) and gluon mass ansatz, approximate Hamiltonians
for heavy quarkonia and triply-heavy baryons in QCD were found [1,2].
The approximate eigenfunctions of these Hamiltonians are used to obtain
the results for form factors and structure functions. Charge radii that
are calculated from the form factors are in the ballpark of expectations
based on other theoretical results. The results for radii are in a
surprisingly good agreement with lattice QCD results in cases where
comparison is possible. The crudeness of approximations of the wave
functions, however, presents a problem for calculations of magnetic
properties of hadrons and for relativistic covariance of scattering
amplitudes. To estimate corrections necessary to obtain reliable results
for magnetic moments of spin-$1/2$ and spin-$1$ hadrons, we construct
corrections to the wave functions using free quark spinors.
These corrections approximately restore rotational covariance of the
scattering amplitudes and allow us to give estimates of the magnetic
moments. Magnetic moments of vector charmonia and bottomonia are in
agreement with other theoretical results. Magnetic moments of $B_c^*$ mesons
and spin-$1/2$ ground states of $bbc$ and $ccb$ baryons are considerably larger
than moments reported in the literature.
The hadron structure functions are computed in a simplified way,
neglecting the huge difference between the scale of quark binding
and the scale of the virtual photon in deep inelastic scattering
(formally infinite). The calculations show interesting features,
such as dependence of the structure function shape on the wave
function nodes. However, these calculations can be considered
merely a demonstration of potential utility of the method, because
the transformation that connects effective particles at two different
RGPEP scales, that of DIS and that of bound-state formation, is
approximated by identity.
[1] Głazek, Gómez-Rocha, More, Serafin, Phys. Lett. B 773, 172 (2017)
[2] Serafin, Gómez-Rocha, More, Głazek, Eur. Phys. J. C 78, 964 (2018)