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.

/pdf/heavy-quarkonium-progress-puzzles-and-opportunities-2tru0l8jyp.pdf

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

The charmonium-nucleon interaction is studied by the time-dependent HAL QCD method. We use a larger lattice volume and the relativistic heavy quark action for charm quark to obtain less systematic errors than those in our previous study. As a result, the sizable J/$\psi$N hyperfine splitting is observed, indicating that the spin-spin interaction is important to understand this system quantitatively. No J/$\psi$N or $\eta_c$N bound state is observed below the thresholds as in the previous results.

Charmonium-nucleon interactions from 2+1 flavor lattice QCD

http://inspirehep.net/record/798275/files/arXiv:0810.0351.pdf

SU(2) and SU(3) chiral perturbation theory analyses on meson and baryon masses in 2+1 flavor lattice QCD

Quenched lattice QCD results of nuclear forces are presented. Inter-nucleon potentials are constructed from Bethe-Salpeter wave functions of two nucleon states by using a Schrodinger-type equation. The results of the central force in 1S0 channel posses the repulsive core at short distance as well as the attraction at medium distance, both of which are enhanced in the light quark mass region. A preliminary result on the tensor force is also presented with the central force in 3S1 channel.

Lattice qcd calculation of nuclear forces

We study the manifestly exotic tetraquark D$_{\rm s0}^{++}(cu\bar s \bar d)$ and the scalar tetraquark $f_0(ud \bar u \bar d)$ in SU(3)$_c$ anisotropic quenched lattice QCD with the $O(a)$-improved Wilson (clover) fermion with various quark masses including the idealized SU(4)$_f$ case. For $f_0(ud\bar u \bar d)$ etc., we only consider connected diagrams at the quenched level, i.e., the tetraquark $f_0(ud\bar u\bar d)$ is identical with D$_{\rm s0}^{++} (cu\bar s \bar d)$ in the idealized SU(4)$_f$ case. First, for comparison, we study the lowest $q\bar q$ scalar meson, and find that it has a large mass of about 1.37GeV after chiral extrapolation, which corresponds to $f_0(1370)$. Second, we investigate the lowest 4Q state in the spatial periodic boundary condition, and find that it is just a scattering state of two pseudoscalar mesons, as is expected. Third, to extract spatially-localized 4Q resonances, we use the Hybrid Boundary Condition (HBC) method, where anti-periodic and periodic boundary conditions are imposed on quarks ($c$,$u$) and antiquarks ($\bar s$,$\bar d$), respectively. By applying the HBC on a finite-volume lattice, the threshold of the two-meson scattering state is raised up, while the mass of a compact 4Q resonance is almost unchanged. In HBC, we find a nontrivial 4Q resonance state about 100 MeV below the two-meson threshold in some quark-mass region. Its chiral behavior largely differs from a two-meson scattering state. The scalar tetraquark $f_0(ud\bar u\bar d)$ is found to have the mass of about 1.1GeV after chiral extrapolation, and seems to correspond to $f_0(980)$. Then, the manifestly exotic tetraquark D$_{\rm s0}^{++}(cu\bar s \bar d)$ would exist around 1GeV in the idealized SU(4)$_f$ chiral limit. Finally, MEM analysis is applied to obtain the spectral function of the 4Q system.

/pdf/lattice-qcd-evidence-for-exotic-tetraquark-resonance-edwrpz4m3t.pdf

Lattice QCD Evidence for Exotic Tetraquark Resonance

A novel Lattice QCD (LQCD) method to determine the quark–diquark (q–D) interaction potential together with the diquark mass (
 $$m_D$$
 ) is proposed. Similar to the HAL QCD method, q–D potential is determined by demanding it to reproduce the q–D equal-time Nambu–Bethe–Salpeter (NBS) wave function. To do this, it is necessary to use the masses of the quark and the diquark as inputs, which however are not straightforwardly obtained because of the color confinement of QCD. In this work, masses of quark and diquark are determined by demanding that the p-wave spectrums from the two-point correlators be reproduced by the potentials for $$c{\bar{c}}$$
 and q–D sectors determined from the NBS wave functions. Numerical calculations are performed by using 2+1 flavor QCD gauge configurations with the pion mass $$m_\pi \simeq 700$$
 MeV generated by PACS-CS collaboration. We apply our method to the c–
 $${\bar{c}}$$
 system and the charm-diquark system (
 $$\Lambda _c$$
 baryon) to obtain the charm quark mass, diquark mass and the c–D potential. Our preliminary analysis leads to the diquark mass $$m_D \simeq 1.127$$
  GeV which is roughly consistent with a naive estimate based on the constituent quark picture, i.e., $$m_{D} \simeq m_{\rho } \simeq 1.12$$
  GeV and $$m_{D} \simeq 2m_N/3 \simeq 1.06$$
  GeV.

Noriyoshi Ishii

Papers

Charmonium-nucleon interactions from 2+1 flavor lattice QCD

SU(2) and SU(3) chiral perturbation theory analyses on meson and baryon masses in 2+1 flavor lattice QCD

Lattice qcd calculation of nuclear forces

Lattice QCD Evidence for Exotic Tetraquark Resonance

Building Diquark Model from Lattice QCD