29,369 research outputs found
Possible and Molecular states in a chiral quark model
We perform a systematic study of the bound state problem of and
systems by using effective interaction in our chiral quark model.
Our results show that both the interactions of and states
are attractive, which consequently result in
and bound states.Comment: arXiv admin note: substantial text overlap with arXiv:1204.395
Pion Interferometry for Hydrodynamical Expanding Source with a Finite Baryon Density
We calculate the two-pion correlation function for an expanding hadron source
with a finite baryon density. The space-time evolution of the source is
described by relativistic hydrodynamics and the Hanbury-Brown-Twiss (HBT)
radius is extracted after effects of collective expansion and multiple
scattering on the HBT interferometry have been taken into account, using
quantum probability amplitudes in a path-integral formalism. We find that this
radius is substantially smaller than the HBT radius extracted from the
freeze-out configuration.Comment: 4 pages, 2 figure
Relativistic Modification of the Gamow Factor
In processes involving Coulomb-type initial- and final-state interactions,
the Gamow factor has been traditionally used to take into account these
additional interactions. The Gamow factor needs to be modified when the
magnitude of the effective coupling constant increases or when the velocity
increases. For the production of a pair of particles under their mutual
Coulomb-type interaction, we obtain the modification of the Gamow factor in
terms of the overlap of the Feynman amplitude with the relativistic wave
function of the two particles. As a first example, we study the modification of
the Gamow factor for the production of two bosons. The modification is
substantial when the coupling constant is large.Comment: 13 pages, in LaTe
Measurement of Cosmic-ray Muons and Muon-induced Neutrons in the Aberdeen Tunnel Underground Laboratory
We have measured the muon flux and production rate of muon-induced neutrons
at a depth of 611 m water equivalent. Our apparatus comprises three layers of
crossed plastic scintillator hodoscopes for tracking the incident cosmic-ray
muons and 760 L of gadolinium-doped liquid scintillator for producing and
detecting neutrons. The vertical muon intensity was measured to be cmssr. The yield of
muon-induced neutrons in the liquid scintillator was determined to be
neutrons/(gcm). A fit to the recently measured neutron
yields at different depths gave a mean muon energy dependence of for liquid-scintillator targets.Comment: 14 pages, 17 figures, 3 table
Neural processes of proactive and reactive controls modulated by motor-skill experiences
This study investigated the experience of open and closed motor skills on modulating proactive and reactive control processes in task switching. Fifty-four participants who were open-skilled
- …