1,345 research outputs found
Y-type Flux-Tube Formation and Gluonic Excitations in Baryons: From QCD to Quark Model
Using SU(3) lattice QCD, we perform the first systematic study for the
ground-state three-quark (3Q) potential and the 1st
excited-state 3Q potential , {\it i.e.}, the energies of
the ground state and the 1st excited state of the gluon field in the presence
of the static three quarks. From the accurate and thorough calculation for more
than 300 different patterns of 3Q systems, the static ground-state 3Q potential
is found to be well described by the Coulomb plus
Y-type linear potential, {\it i.e.}, Y-Ansatz, within 1%-level deviation. As a
clear evidence for Y-Ansatz, Y-type flux-tube formation is actually observed on
the lattice in maximally-Abelian projected QCD. For more than 100 patterns of
3Q systems, we calculate the 1st excited-state 3Q potential in quenched lattice QCD, and find the gluonic excitation energy to be about 1
GeV. This large gluonic-excitation energy is conjectured to ensure the success
of the quark model for the low-lying hadrons even without gluonic excitations.Comment: Talk given at International Conference on Color Confinement and
Hadrons in Quantum Chromodynamics - Confinement 2003, RIKEN, Japan, 21-24 Jul
200
Meson-Meson and Meson-Baryon Interactions in Lattice QCD
We study the meson-meson and meson-baryon interactions in lattice QCD. The
simulation is performed on 20^3 * 24 lattice at \beta=5.7 using Wilson gauge
action and Wilson fermion at the quenched level. By adopting one static quark
for each hadron as "heavy-light meson" and "heavy-light-light baryon", we
define the distance of two hadrons and extract the inter-hadron potential
from the energy difference of the two-particle state and its asymptotic state.
We find that both of the meson-meson and meson-baryon potentials are
nontrivially weak for the whole range of 0.2 fm <= r <= 0.8 fm. The effect of
including/excluding the quark-exchange diagrams is found to be marginal.Comment: Talk given at Particles and Nuclei International Conference
(PANIC05), Santa Fe, NM, USA, 24-28 Oct. 2005. 3 pages, 2 figure
Falling Snow Melting Characteristics of Warm Water Flowing along Sheet Channels Spread on a Roof
The experiment for investigating the falling snow melting characteristics of warm water flowing along sheet channels spread on a roof was performed in Tookamachi city, Nigata prefecture from February 6 to February 7, 1995. The sheet surface temperatures at 11 positions in 3 channels were measured. A physical model for a gas-water-snow system was constructed to compare the predicted results with the measured ones. A fully spread uniform water film in the sheet channel was observed in the experiments. The experimental results elucidated that it was feasible to use warm water flowing along sheet channels for melting falling snow on roofs. The temperature drop in the sheet
channel mainly depended on the snowfall intensity, atmospheric temperature and wind speed. Under the influence of the roof edge, the temperature drop in the channel next to the side edge was much larger than that in middle channels. A water-snow two phase flow or a snow covered frozen water was experienced temporarily in the lower reaches of the water flowing channel. These suggest that a larger water flow rate is needed for the channel next to the roof edge, and a higher inlet temperature or a greater water flow rate is required for a severe weather condition. There was reasonably good agreement between the measured and predicted water temperatures
Multi-Quarks and Two-Baryon Interaction in Lattice QCD
We study multi-quark (3Q,4Q,5Q) systems in lattice QCD. We perform the
detailed studies of multi-quark potentials in lattice QCD to clarify the
inter-quark interaction in multi-quark systems. We find that all the
multi-quark potentials are well described by the OGE Coulomb plus multi-Y-type
linear potential, i.e., the multi-Y Ansatz. For multi-quark systems, we observe
lattice QCD evidences of ``flip-flop'', i.e., flux-tube recombination. These
lattice QCD studies give an important bridge between elementary particle
physics and nuclear physics.Comment: A talk given at Particles and Nuclei International
Conference(PANIC05), Santa Fe, NM, Oct. 24-28, 2005. 3 pages, 6 figure
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