Negative Parity Baryons in the QCD Sum Rule

Masses and couplings of the negative parity excited baryons are studied in the QCD sum rule. Separation of the negative-parity spectrum is proposed and is applied to the flavor octet and singlet baryons. We find that the quark condensate is responsible for the mass splitting of the ground and the negative-parity excited states. This is expected from the chiral symmetry and supports the idea that the negative-parity baryon forms a parity doublet with the ground state. The meson-baryon coupling constants are also computed for the excited states in the QCD sum rule. It is found that the \pi NN^* coupling vanishes in the chiral limit.Comment: 13pp, LaTeX, 1 EPS figure, uses epsf.sty, Talk given by M.O. at CEBAF/INT workshop "N* physics", Seattle, September (1996), to appear in the proceeding

Relation between the separable and one-boson-exchange potential for the covariant Bethe-Salpeter equation

We investigate the relation between the rank I separable potential for the covariant Bethe-Salpeter equation and the one-boson-exchange potential. After several trials of the parameter choices, it turns out that it is not always possible to reproduce the phase-shifts calculated from a single term of the one-boson-exchange potential especially of the $\sigma$-exchange term, separately by the rank I separable potential. Instead, it is shown that the separable potential is useful to parameterize the total nucleon-nucleon interaction.Comment: 10 pages, 8 figures, to appear in J.Phys.

Interfaces of correlated electron systems: Proposed mechanism for colossal electroresistance

Mott's metal-insulator transition at an interface due to band bending is studied by the density matrix renormalization group (DMRG). We show that the result can be recovered by a simple modification of the conventional Poisson's equation approach used in semi-conductor heterojunctions. A novel mechanism of colossal electroresistance is proposed, which incorporates the hysteretic behavior of the transition in higher dimensions.Comment: 5 pages, 3 figures, title change

Quantum description for a chiral condensate disoriented in a certain direction in isospace

We derive a quantum state of the disoriented chiral condensate dynamically, considering small quantum fluctuations around a classical chiral condensate disoriented in a certain direction $\vec n$ in isospace. The obtained nonisosinglet quantum state has the characteristic features; (i) it has the form of the squeezed state, (ii) the state contains not only the component of pion quanta in the direction $\vec n$ but also the component in the perpendicular direction to $\vec n$ and (iii) the low momentum pions in the state violate the isospin symmetry. With the quantum state, we calculate the probability of the neutral fraction depending on the time and the pion's momentum, and find that the probability has an unfamiliar form. For the low momentum pions, the parametric resonance mechanism works with the result that the probability of the neutral fraction becomes the well known form approximately and that the charge fluctuation is small.Comment: 19 page

Are the anti-charmed and bottomed pentaquarks molecular heptaquarks?

I study the charmed $uudd\bar c$ resonance D*p (3100) very recently discovered by the H1 collaboration at Hera. An anticharmed resonance was already predicted, in a recent publication mostly dedicated to the S=1 resonance Theta+(1540). To confirm these recent predictions, I apply the same standard quark model with a quark-antiquark annihilation constrained by chiral symmetry. I find that repulsion excludes the D*p (3100) as a $uudd\bar c$ s-wave pentaquark. I explore the D*p (3100) as a heptaquark, equivalent to a N-pi-D* linear molecule, with positive parity and total isospin I=0. I find that the N-D repulsion is cancelled by the attraction existing in the N-pi and pi-D channels. In our framework this state is harder to bind than the Theta+ described by a k-pi-N borromean bound-state, a lower binding energy is expected in agreement with the H1 observation. Multiquark molecules N-pi-D, N-pi-B* and N-pi-B are also predicted.Comment: 5 pages, 2 figures, RevTe

A critical Mach number for electron injection in collisionless shocks

Electron acceleration in collisionless shocks with arbitrary magnetic field orientations is discussed. It is shown that the injection of thermal electrons into diffusive shock acceleration process is achieved by an electron beam with a loss-cone in velocity space that is reflected back upstream from the shock through shock drift acceleration mechanism. The electron beam is able to excite whistler waves which can scatter the energetic electrons themselves when the Alfven Mach number of the shock is sufficiently high. A critical Mach number for the electron injection is obtained as a function of upstream parameters. The application to supernova remnant shocks is discussed.Comment: 4 pages, 2 figure, accepted for publication in Physical Review Letter

A Consistent Study of the the Low Energy Baryon Spectrum and the Nucleon-Nucleon Interaction within the Chiral Quark Model

By solving the Schr\"{o}dinger equation for the three-quark system in the hyperspherical harmonic approach, we have studied the low energy part of the nucleon and $\Delta$ spectra using a quark-quark interaction which reproduces the nucleon-nucleon phenomenology. The quark-quark hamiltonian considered includes, besides the usual one-gluon exchange, pion and sigma exchanges generated by the chiral symmetry breaking. The baryonic spectrum obtained is reasonable and the resulting wave function gives consistency to the ansatz used in the two baryon system.Comment: Accepted for publication in Phys. Lett.

Analisis Manajemen Risiko Kredit Dalam Meminimalisir Kredit Bermasalah Pada Kredit USAha Rakyat (Studi Pada Bank Jatim Cabang Mojokerto)

This research is aimed to analyze the application of credit risk management to minimize non performing loan of Kredit Usaha Rakyat (KUR) in Bank Jatim Cabang Mojokerto and to find out the implementation of effective credit risk management to minimize non performing loan of Kredit Usaha Rakyat (KUR) in Bank Jatim Cabang Mojokerto. The type of research which is used in this study is descriptive research. The findings show that Bank Jatim Cabang Mojokerto has properly implemented active surveillance by commissioners and directors, policies, procedures and credit limitation, the process of identification, measurement, monitoring and credit risk management information systems, and a credit risk controlling. This study suggests the bank to maintain the independency of the credit staffs and improve credit monitoring process