다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Nuclear forces can be systematically derived using effective chiral Lagrangians consistent with the symmetries of QCD. I review the status of the calculations for two- and three-nucleon forces and their applications in few-nucleon systems. I also address issues like the quark mass dependence of the nuclear forces and resonance saturation for four-nucleon operators.

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Modern theory of nuclear forces

A golden age for heavy-quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the B-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations at BESIII, the LHC, RHIC, FAIR, the Super Flavor and/or Tau-Charm factories, JLab, the ILC, and beyond. The list of newly found conventional states expanded to include h(c)(1P), chi(c2)(2P), B-c(+), and eta(b)(1S). In addition, the unexpected and still-fascinating X(3872) has been joined by more than a dozen other charmonium- and bottomonium-like "XYZ" states that appear to lie outside the quark model. Many of these still need experimental confirmation. The plethora of new states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c (c) over bar, b (b) over bar, and b (c) over bar bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. Lattice QCD has grown from a tool with computational possibilities to an industrial-strength effort now dependent more on insight and innovation than pure computational power. New effective field theories for the description of quarkonium in different regimes have been developed and brought to a high degree of sophistication, thus enabling precise and solid theoretical predictions. Many expected decays and transitions have either been measured with precision or for the first time, but the confusing patterns of decays, both above and below open-flavor thresholds, endure and have deepened. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.

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Heavy quarkonium: progress, puzzles, and opportunities

http://cds.cern.ch/record/257993/files/9401310.pdf

QCD phenomenology based on a chiral effective Lagrangian

A large number of experimental discoveries especially in the heavy quarkonium sector that did not at all fit to the expectations of the until then very successful quark model led to a renaissance of hadron spectroscopy Among various explanations of the internal structure of these excitations, hadronic molecules, being analogues of light nuclei, play a unique role since for those predictions can be made with controlled uncertainty We review experimental evidences of various candidates of hadronic molecules, and methods of identifying such structures Nonrelativistic effective field theories are the suitable framework for studying hadronic molecules, and are discussed in both the continuum and finite volumes Also pertinent lattice QCD results are presented Further, we discuss the production mechanisms and decays of hadronic molecules, and comment on the reliability of certain assertions often made in the literature

Hadronic molecules

HAL QCD method is a method to construct a potential (HAL QCD potential) that reproduces the NN scattering phase shift faithful to the QCD. The HAL QCD potential is obtained from QCD by eliminating the degrees of freedom of quarks and gluons and leaving only two particular hadrons. Therefor, in the effective quantum mechanics of two nucleons defined by HAL QCD potential, the conserved current consists not only of the nucleon current but also an extra current originating from the potential (two-body current). Though the form of the two-body current is closely related to the potential, it is not straight forward to extract the former from the latter. In this work, we derive the the current matrix element formula in the quantum mechanics defined by the HAL QCD potential. As a first step, we focus on the non-relativistic case. To give an explicit example, we consider a second quantized non-relativistic two-channel coupling model which we refer to as the original model. From the original model, the HAL QCD potential for the open channel is constructed by eliminating the closed channel in the elastic two-particle scattering region. The current matrix element formula is derived by demanding the effective quantum mechanics defined by the HAL QCD potential to respond to the external field in the same way as the original two-channel coupling model.

/pdf/the-current-matrix-elements-from-hal-qcd-method-3zrw0urdfb.pdf

The current matrix elements from HAL QCD method

We study pΞ0 and pΛ forces by using quenched lattice QCD. The Bethe-Salpeter amplitude is calculated for the lowest scattering state of the systems. The numerical calculation is twofold: (i) For the pΞ0, the potentials and scattering lengths are obtained by using 323 × 32 lattice with β = 5.7, the lattice spacing of a = 0.1416(9) fm, and two kinds of ud quark mass corresponding to mπ ≃ 0.37 GeV and 0.51 GeV. The present results indicate that the pΞ0 interactions are both attractive at 1S0 and 3S1 channels, and the interaction in the 3S1 is more attractive than in the 1S0. These attractive forces become stronger as the u, d quark mass decreases. (ii) For the pΛ, the potentials are calculated by using the 323 × 48 lattice, and two kinds of ud quark mass corresponding to mπ ≃ 0.47 GeV and 0.51 GeV. The present preliminary result shows that the pΛ interactions are both attractive at 1S0 and 3S1 channels.

Study of hyperon-nucleon potential from lattice QCD

We give a formula to calculate a matrix element of a conserved current in the effective quantum mechanics defined by the wave function equivalent potentials proposed by HAL QCD collaboration. As a first step, a non-relativistic field theory with two channel coupling is considered as the original theory, with which a wave function equivalent HAL QCD potential is obtained in a closed analytic form. The external field method is used to derive the formula by demanding that the result should agree with the original theory. With this formula, the matrix element is obtained by sandwiching the effective current operator between the left and the right eigen functions of the effective Hamiltonian associated with the HAL QCD potential. In addition to the naive one-body current, the effective current operator contains an additional two-body term emerging from the degrees of freedom which has been integrated out.

Current matrix element in HAL QCD's wave function equivalent potential method

We study the hyperon-nucleon (YN) forces by using quenched lattice QCD. The Bethe-Salpeter amplitudes are calculated for the lowest scattering state of the systems so as to obtain the YN potentials. The numerical calculation is twofold: (i) The pΞ0 potentials and scattering lengths are obtained by using lattice QCD with β = 5.7, the lattice spacing of a = 0.1416(9) fm, on the 323 × 32 lattice. Two kinds of ud quark mass are used, corresponding to mπ ≃ 0.37 GeV and 0.51 GeV. The spatial lattice volume is (4.5 fm)3. The scattering lengths obtained from Luscher's formula show that the pΞ0 interactions are both attractive at 1S0 and 3S1 channels, and the interaction in the 3S1 is more attractive than in the 1S0. These attractive forces become stronger as the u, d quark mass decreases. (ii) The pΛ potentials are calculated. The lattice setup is almost same as the former calculation except for the temporal part. The calculation is performed on 323 × 48 lattice. Two kinds of ud quark mass are used, corresponding...

Hyperon-nucleon forces calculated from lattice qcd

We examine the properties of the wave-function-equivalent potentials which HAL QCD collaboration has introduced. We generalize the derivative expansion, and then apply it to energy-independent and non-local potentials in a coupled-channel model. We observe that the expansion converges by comparing the scattering phase shifts computed from these potentials with the exact one. We have also found that the convergence can be improved by either varying the choice of interpolating fields or tuning the expansion scale in the generalized derivative expansion. The results will be utilized in future lattice QCD calculations, allowing for further application of the HAL QCD method.

Noriyoshi Ishii

Papers

The current matrix elements from HAL QCD method

Study of hyperon-nucleon potential from lattice QCD

Current matrix element in HAL QCD's wave function equivalent potential method

Hyperon-nucleon forces calculated from lattice qcd

Properties of non-local wave function equivalent potential with generalized derivative expansion