Nonlocal calculation for nonstrange dibaryons and tribaryons

We study the possible existence of nonstrange dibaryons and tribaryons by solving the bound-state problem of the two- and three-body systems composed of nucleons and deltas. The two-body systems are $NN$, $N\Delta$, and $\Delta\Delta$, while the three-body systems are $NNN$, $NN\Delta$, $N\Delta\Delta$, and $\Delta\Delta\Delta$. We use as input the nonlocal $NN$, $N\Delta$, and $\Delta\Delta$ potentials derived from the chiral quark cluster model by means of the resonating group method. We compare with previous results obtained from the local version based on the Born-Oppenheimer approximation.Comment: 19 pages. To be published in Physical Review

Nuclear Force from Monte Carlo Simulations of Lattice Quantum Chromodynamics

The nuclear force acting between protons and neutrons is studied in the Monte Carlo simulations of the fundamental theory of the strong interaction, the quantum chromodynamics defined on the hypercubic space-time lattice. After a brief summary of the empirical nucleon-nucleon (NN) potentials which can fit the NN scattering experiments in high precision, we outline the basic formulation to derive the potential between the extended objects such as the nucleons composed of quarks. The equal-time Bethe-Salpeter amplitude is a key ingredient for defining the NN potential on the lattice. We show the results of the numerical simulations on a $32^4$ lattice with the lattice spacing $a \simeq 0.137$fm (lattice volume (4.4 fm)$^4$) in the quenched approximation. The calculation was carried out using the massively parallel computer Blue Gene/L at KEK. We found that the calculated NN potential at low energy has basic features expected from the empirical NN potentials; attraction at long and medium distances and the repulsive core at short distance. Various future directions along this line of research are also summarized.Comment: 13 pages, 4 figures, version accepted for publication in "Computational Science & Discovery" (IOP

Spin observables of the reactions NN -> DeltaN and pd -> Delta (pp)(1S0) in collinear kinematics

A general formalism for double and triple spin-correlations of the reaction NN -> DeltaN is developed for the case of collinear kinematics. A complete polarization experiment allowing to reconstruct all of the four amplitudes describing this process is suggested. Furthermore, the spin observables of the inelastic charge-exchange reaction pd -> Delta^0(pp)(1S0) are analyzed in collinear kinematics within the single pN scattering mechanism involving the subprocess pn -> Delta^0p. The full set of spin observables related to the polarization of one or two initial particles and one final particle is obtained in terms of three invariant amplitudes of the reaction pd -> Delta (pp)(1S0) and the transition form factor d->(pp)(1S0). A complete polarization experiment for the reaction pd -> Delta^0(pp)(1S0) is suggested which allows one to determine three independent combinations of the four amplitudes of the elementary subprocess NN -> DeltaN.Comment: 12 pages, 1 figur

Quark-model study of few-baryon systems

We review the application of non-relativistic constituent quark models to study one, two and three non-strange baryon systems. We present results for the baryon spectra, potentials and observables of the NN, N$\Delta$, $\Delta\Delta$ and NN$^*(1440)$ systems, and also for the binding energies of three non-strange baryon systems. We make emphasis on observable effects related to quark antisymmetry and its interplay with quark dynamics.Comment: 82 pages, 36 figures, 18 tables. Accepted for publication in Reports on Progress in Physic

Soft-core hyperon-nucleon potentials

A new Nijmegen soft-core OBE potential model is presented for the low-energy YN interactions. Besides the results for the fit to the scattering data, which largely defines the model, we also present some applications to hypernuclear systems using the G-matrix method. An important innovation with respect to the original soft-core potential is the assignment of the cut-off masses for the baryon-baryon-meson (BBM) vertices in accordance with broken SU(3)$_F$, which serves to connect the NN and the YN channels. As a novel feature, we allow for medium strong breaking of the coupling constants, using the $^3P_0$ model with a Gell-Mann--Okubo hypercharge breaking for the BBM coupling. We present six hyperon-nucleon potentials which describe the available YN cross section data equally well, but which exhibit some differences on a more detailed level. The differences are constructed such that the models encompass a range of scattering lengths in the $\Sigma N$ and $\Lambda N$ channels. For the scalar-meson mixing angle we obtained values $\theta_S=37$ to 40 degrees, which points to almost ideal mixing angles for the scalar $q\bar{q}$ states. The G-matrix results indicate that the remarkably different spin-spin terms of the six potentials appear specifically in the energy spectra of $\Lambda$ hypernuclei.Comment: 37 pages, 4 figure

Nucleon-Nucleon Interaction: A Typical/Concise Review

Nearly a recent century of work is divided to Nucleon-Nucleon (NN) interaction issue. We review some overall perspectives of NN interaction with a brief discussion about deuteron, general structure and symmetries of NN Lagrangian as well as equations of motion and solutions. Meanwhile, the main NN interaction models, as frameworks to build NN potentials, are reviewed concisely. We try to include and study almost all well-known potentials in a similar way, discuss more on various commonly used plain forms for two-nucleon interaction with an emphasis on the phenomenological and meson-exchange potentials as well as the constituent-quark potentials and new ones based on chiral effective field theory and working in coordinate-space mostly. The potentials are constructed in a way that fit NN scattering data, phase shifts, and are also compared in this way usually. An extra goal of this study is to start comparing various potentials forms in a unified manner. So, we also comment on the advantages and disadvantages of the models and potentials partly with reference to some relevant works and probable future studies.Comment: 85 pages, 5 figures, than the previous v3 edition, minor changes, and typos fixe

Polarization transfer in the 16^{16}O(p,p′)(p,p') reaction at forward angles and structure of the spin-dipole resonances

Cross sections and polarization transfer observables in the $^{16}$O$(p,p')$ reactions at 392 MeV were measured at several angles between $\theta_{lab}=$ 0$^\circ$ and 14$^\circ$. The non-spin-flip (${\Delta}S=0$) and spin-flip (${\Delta}S=1$) strengths in transitions to several discrete states and broad resonances in $^{16}$O were extracted using a model-independent method. The giant resonances in the energy region of $E_x=19-$27 MeV were found to be predominantly excited by ${\Delta}L=1$ transitions. The strength distribution of spin-dipole transitions with ${\Delta}S=1$ and ${\Delta}L=1$ were deduced. The obtained distribution was compared with a recent shell model calculation. Experimental results are reasonably explained by distorted-wave impulse approximation calculations with the shell model wave functions.Comment: 28 pages RevTex, including 9 figures, to be published in Phys. Rev. C.; a typo in Eq. (3b) was correcte

Microwave Current Imaging in Passive HTS Components by Low-Temperature Laser Scanning Microscopy (LTLSM)

We have used the LTLSM technique for a spatially resolved investigation of the microwave transport properties, nonlinearities and material inhomogeneities in an operating coplanar waveguide YBa_2Cu_3O_{7-\delta} (YBCO) microwave resonator on an LaAlO_3 (LAO) substrate. The influence of twin-domain blocks, in-plane rotated grains, and micro-cracks in the YBCO film on the nonuniform rf current distribution were measured with a micrometer-scale spatial resolution. The impact of the peaked edge currents and rf field penetration into weak links on the linear device performance were studied as well. The LTLSM capabilities and its future potential for non-destructive characterization of the microwave properties of superconducting circuits are discussed.Comment: 8 pages, 9 figures, 2-column format, presented at High Temperature Superconductors in High Frequency Fields 2004, Journal of Superconductivity (in press

Ecosystem Services in Conservation Planning: Targeted Benefits vs. Co-Benefits or Costs?

There is growing support for characterizing ecosystem services in order to link conservation and human well-being. However, few studies have explicitly included ecosystem services within systematic conservation planning, and those that have follow two fundamentally different approaches: ecosystem services as intrinsically-important targeted benefits vs. substitutable co-benefits. We present a first comparison of these two approaches in a case study in the Central Interior of British Columbia. We calculated and mapped economic values for carbon storage, timber production, and recreational angling using a geographical information system (GIS). These ‘marginal’ values represent the difference in service-provision between conservation and managed forestry as land uses. We compared two approaches to including ecosystem services in the site-selection software Marxan: as Targeted Benefits, and as Co-Benefits/Costs (in Marxan's cost function); we also compared these approaches with a Hybrid approach (carbon and angling as targeted benefits, timber as an opportunity cost). For this analysis, the Co-Benefit/Cost approach yielded a less costly reserve network than the Hybrid approach (1.6% cheaper). Including timber harvest as an opportunity cost in the cost function resulted in a reserve network that achieved targets equivalently, but at 15% lower total cost. We found counter-intuitive results for conservation: conservation-compatible services (carbon, angling) were positively correlated with each other and biodiversity, whereas the conservation-incompatible service (timber) was negatively correlated with all other networks. Our findings suggest that including ecosystem services within a conservation plan may be most cost-effective when they are represented as substitutable co-benefits/costs, rather than as targeted benefits. By explicitly valuing the costs and benefits associated with services, we may be able to achieve meaningful biodiversity conservation at lower cost and with greater co-benefits