314 research outputs found
Chiral Symmetry of Baryons
We study chiral symmetry aspects of the positive and negative parity baryons
by identifying them with linear representations of the chiral group . It is shown that there are two distinctive schemes: naive
and mirror assignments. We construct linear sigma models for baryons in the two
assignments and examine their physical implications. Then we investigate
properties of the naive and mirror nucleons microscopically by using QCD
interpolating fields. Finally, we propose experiments to distinguish the two
chiral assignments for the nucleon.Comment: 36 pages, To appear in Prog. Theor. Phy
Quark Confinement for Multi-Quark Systems -- Application to Fully-Charmed Tetraquarks
A new color basis system and confinement mechanism for multi-quark systems
are proposed according to the string-type picture of QCD. The color string
configurations in the strong coupling QCD are implemented in the set of color
basis states. The extended color Hilbert space for systems
includes a ''hidden color'' state, which mixes with two-meson states , This mixing effect leads to an attractive potential sufficient to
form a bound state. We apply a realistic Hamiltonian model with the new scheme
to fully charmed tetraquark states, , and find a bound and two
resonant states, which could potentially correspond to the
tetraquark candidates recently observed in experiments.Comment: 6 pages, 3 figure
The Suppression of Contact Sensitivity Induction by Tape Stripping Treatment of Guinea Pig Skin at Various Times before and after Injection of Haptenated Epidermal Cells
Antioxidant Activity and Oxidation Products of 1,2,3,4- Tetrahydroquinoxalines in Peroxyl Radical Scavenging Reactions, Part I
This paper studies the antioxidant activity of 1,2,3,4-tetrahydroquinolines, 3,4-dihydro-2H-benzo[1,4]thiazines and 1,2,3,4-tetrahydroquinoxalines in the inhibition of the peroxidation of tetralin induced by an azo initiator. Neither 1,2,3,4- tetrahydroquinoline nor 3,4-dihydro-2H-benzo[1,4]thiazine alone acted as an antioxidant, but when they have an electron-donating group at the para position to the NH group, they act as potent antioxidants. On the other hand, 1,2,3,4- tetrahydroquinoxaline on its own showed good antioxidant activity. However, 1,2,3,4-tetrahydroquinoxalines with methyl and methoxy groups in the phenyl ring have reactivities similar to or less than that of unsubstituted 1,2,3,4-tetrahydroquinoxaline. The induction periods of 1,2,3,4-tetrahydroquinoxalines with an alkyl group or phenyl group at the 2-position were all longer than the value for the unsubstituted 1,2,3,4-tetrahydroquinoxaline, except for a compound with a t-butyl group. The oxidation of 1,2,3,4-tetrahydroquinoxalines by peroxyl radicals generated from an azo initiator in tetralin or benzene yields quinoxalines and a dimer product of quinoxalines, 6-(1,2,3,4-tetrahydroquinoxalin-1-yl)-quinoxaline
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