相关论文: New Family of Exotic $\Theta$-Baryons
From the interpretation of the $\Theta^+(1540)$ and $\Xi_{3/2}(1862)$ baryons as an excitation of the ``skyrmion liquid'' with SU(3) flavour symmetry $\bar{10}$ we deduce a new series of baryons, $\Theta_1^{++}$, $\Theta_1^{+}$ and…
Motivated by the recent discovery of the exotic S=+1 narrow baryon resonance Theta^+ at 1540 MeV, with quark content {uudd sbar}, we conjecture the existence of its anti-charmed analogue Theta_c, with quark content {uudd cbar}, and compute…
The 1/N expansion for exotic baryons is developed, and applied to the masses, meson couplings and decay widths. Masses and widths of the 27 and 35 pentaquark states in the same tower as the Theta+ are related by spin-flavor symmetry. The 27…
Twenty years ago, in 2003, two experimental groups, LEPS and DIANA, announced the discovery of a light, narrow, exotic baryon with mass within the range of 1540 MeV, which was later dubbed as $\Theta^+$. In this talk we recall the history…
We use the perturbation method to calculate the masses and widths for 27-plet baryons with spin 3/2 from chiral soliton models. According to the masses and quantum numbers, we find all the candidates for non-exotic members of 27-plet. The…
The experimental signature of an S=+1 baryon of mass 1540 MeV and width 10-25 MeV has led to speculation that this is an exotic baryon consisting of 4 quarks and 1 antiquark lying at the top of a $\bar{10}$ SU(3) multiplet. The observed…
We propose that the recently discovered \Theta baryon is a bound state of four quarks and an antiquark, containing two highly correlated ud-pairs. If so, the \Theta baryon has positive parity, and it lies in an near-ideally mixed SU(3)_{f}…
We re-analyze the predictions of chiral-soliton models for the masses and decay widths of baryons in the exotic antidecuplet of flavour SU(3). The calculated ranges of the chiral-soliton moment of inertia and the \pi-nucleon scattering…
We investigate the spin 3/2 baryons in the 27-plet based on flavor SU(3) symmetry. For $J^p=3/2^+$, we find all the candidates for non-exotic members. For $J^p=3/2^-$, we predict a new non-exotic member $\Lambda(1780)$. Fitting the mass…
We suggest to classify baryon resonances as single-quark states in a mean field, and/or as its collective excitations. Identifying the Roper resonance N(1440), the nucleon resonance N(1535), and the singlet hyperon Lambda(1405) as…
Considering simultaneously isospin and SU(3) flavor symmetry breakings, we investigate the complete mass splittings of SU(3) baryons within a chiral soliton model, a {}"model-independent approach" being employed. In linear order several new…
Evidence for the existence of exotic, pentaquark baryons was first found in the invariant mass spectrum of a baryon-meson pair, with the baryon in the octet of flavor SU(3). Exotic pentaquarks may also decay into members of the spin-3/2…
The existence of a light S=+1 baryon resonance follows from Quantum Field Theory applied to baryons. This is illustrated in the Skyrme model (where Theta+ exists but is too strong) and in a new mean field approach where Theta+ arises as a…
If the number of colors Nc is taken large, baryons and their excitations can be considered in a mean-field approach. We argue that the mean field in baryons breaks spontaneously the spherical and SU(3) flavor symmetries, but retains the…
In 1997 Diakonov, Petrov, and Polyakov, calculated the width of the exotic baryon that they called $\Theta^{+}$. The prediction, $\Gamma(\Theta^{+})\lesssim$ 15 MeV, has received considerable attention, especially in light of the narrowness…
We examine several assignments of spin and parity for the pentaquark Theta+ state (J^P=1/2^{+,-}, 3/2^{+,-}) in connection with known baryon resonances. Assuming that the Theta+ belongs to an antidecuplet representation which mixes with an…
The masses of positive $[{\bf 70},0^+]$ and $[{\bf 70},2^+]$ nonstrange and strange baryons are calculated in the $1/N_c$ expansion. The approach is based on the separation of a system of $N_c$ quarks into an excited core and an excited…
Recent experimental evidence for the Theta^+(1540) has given rise to much theoretical interest in exotic baryons. The Theta^+ is a baryon that has strangeness S=+1, meaning that it contains an anti-strange quark. Thus it cannot be…
We illustrate the exotic SU(3) baryon sub-multiplets in the SU(4) baryon multiplets predicted from the flavor SU(4) collective-coordinate quantization, and investigate the exotic states with charm number $C=\pm1$ up to leading order of…
Given the existing empirical information about the exotic Theta+ baryon, we analyze possible properties of its SU(3)F-partners, paying special attention to the nonstrange member of the antidecuplet N*. The modified piN partial-wave analysis…