Pentaquarks: Theory Overview, and Some More about Quark Models
نویسنده
چکیده
At the PANIC conference in Osaka in October 2002, a collaboration working at SPring-8 announced a baryon state, the Θ(1540) with a decay mode Θ → nK. Assuming the decay is not Weak, that meant it had strangeness +1, and therefore was an exotic state (“exotic” in the sense that it is a baryon that cannot be a q state). It can be a ududs̄ state: a pentaquark. It has since been found at other labs by other collaborations, and also has failed to be seen in some experiments: an experimental review follows this talk. In terms of flavor, considering u, d, and s quarks, a quark is in a 3 representation and an antiquark is in a 3̄, and the relevant product is
منابع مشابه
Dynamics of pentaquarks in constituent quark models: recent developments
Some recent developments in the study of light and heavy pentaquarks are reviewed, mainly within constituent quark models. Emphasis is made on results obtained in the flavor-spin model where a nearly ideal octet-antidecuplet mixing is obtained. The charmed antisextet is reviewed in the context of an SU(4) classification.
متن کامل44 2 v 1 2 5 M ar 1 99 8 Positive parity pentaquarks in a Goldstone boson exchange model
We study the stability of the pentaquarks uuddQ, uudsQ and udssQ (Q = c, b, or t) of positive parity in a constituent quark model based on Goldstone boson exchange interaction between quarks. The pentaquark parity is the antiquark parity times that of a quark excited to a p-shell. We show that the Goldstone boson exchange interaction favors these pentaquarks much more than the negative parity o...
متن کاملQCD, hadrons and beyond
I give a summary of Section E of the sixth edition of the Conference Quark confinement and the hadron spectrum. Papers were presented on different subjects, from spectroscopy, including pentaquarks and hadron structure, to new physics effects (non commutative field theories, supersymmetry and extra dimensions) and the problem of color confinement, both in ordinary Yang-Mills models and in super...
متن کاملThe Discovery and Properties of Pentaquarks
The pentaquarks are exotic baryons formed of four quarks and an antiquarks. Their existence has been discussed in the literature over the last 30 years or more, first in connection with kaon nucleon scattering data. The subject has been revived by the end of 2002 when experimental evidence of a narrow baryon of strangeness S = + 1, and mass M ≃ 1530 MeV has been found. This is interpreted as th...
متن کاملQCD Sum Rules of Pentaquarks
The spin and parity seem to be crucial to determine the structure of the pentaquarks. In the naive quark models, the ground state in which all the quarks occupy the lowest energy mode should have negative parity. We expect both the 1/2 or 3/2 states, whose splitting is given by the spin-spin interaction between quarks.[3,4] On the other hand, various model calculations predict a positive parity...
متن کامل