26 research outputs found
On the physics behind the form factor ratio
We point out that there exist two natural definitions of the nucleon
magnetization densities : the density introduced in Kelly's
phenomenological analysis and theoretically more standard one . We
can derive an explicit analytical relation between them, although Kelly's
density is more useful to disentangle the physical origin of the different
dependence of the Sachs electric and magnetic form factors of the
nucleon. We evaluate both of and as well as the
charge density of the proton within the framework of the chiral
quark soliton model, to find a noticeable qualitative difference between
and , which is just consistent with Kelly's result
obtained from the empirical information on the Sachs electric and magnetic form
factors of the proton.Comment: 12 pages, 5 figures. version to appear in J. Phys. G.: Nucl. Part.
Phy
Generalized form factors, generalized parton distributions and the spin contents of the nucleon
With a special intention of clarifying the underlying spin contents of the
nucleon, we investigate the generalized form factors of the nucleon, which are
defined as the -th -moments of the generalized parton distribution
functions, within the framework of the chiral quark soliton model. A particular
emphasis is put on the pion mass dependence of final predictions, which we
shall compare with the predictions of lattice QCD simulations carried out in
the so-called heavy pion region around . We find that some observables are very sensitive to the variation of
the pion mass. It will be argued that the negligible importance of the quark
orbital angular momentum indicated by the LHPC and QCDSF lattice collaborations
might be true in the unrealistic heavy pion world, but it is not necessarily
the case in our real world close to the chiral limit.Comment: Final version accepted for publication in Phys. Rev.
A search for non-random cosmic-ray time series by a cluster analysis
Non-random time series of cosmic rays were searched for in air shower data of mean energy 1:1 x 1015 eV, collected by the air shower array atMitsuishi, Japan, during the period from January 1989 to October 1996. By clustering the arrival time of air showers, five occasions of rate elevation phenomena were found with an expected probability 0:05 (varying from 0:18 x 1