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

Physics welcomes the idea that space contains energy whose gravitational effect approximates that of Einstein's cosmological constant, \ensuremath{\Lambda}; today the concept is termed dark energy or quintessence. Physics also suggests that dark energy could be dynamical, allowing for the arguably appealing picture of an evolving dark-energy density approaching its natural value, zero, and small now because the expanding universe is old. This would alleviate the classical problem of the curious energy scale of a millielectron volt associated with a constant \ensuremath{\Lambda}. Dark energy may have been detected by recent cosmological tests. These tests make a good scientific case for the context, in the relativistic Friedmann-Lema\^{\i}tre model, in which the gravitational inverse-square law is applied to the scales of cosmology. We have well-checked evidence that the mean mass density is not much more than one-quarter of the critical Einstein--de Sitter value. The case for detection of dark energy is not yet as convincing but still serious; we await more data, which may be derived from work in progress. Planned observations may detect the evolution of the dark-energy density; a positive result would be a considerable stimulus for attempts at understanding the microphysics of dark energy. This review presents the basic physics and astronomy of the subject, reviews the history of ideas, assesses the state of the observational evidence, and comments on recent developments in the search for a fundamental theory.

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The Cosmological Constant and Dark Energy

This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.

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Averages of b-hadron, c-hadron, and tau-lepton properties as of early 2012

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

The hidden-charm pentaquark and tetraquark states

Tree amplitudes for baryon-pion scattering are studied in the 1/N{sub c} expansion. Generalized large-N{sub c} consistency conditions are obtained to all orders in baryon mass splittings. For baryons with spin J{approx}O(1), the leading order in N{sub c} tree amplitudes can be evaluated keeping only terms up to a given finite order in baryon mass splittings. (c) 2000 The American Physical Society.

Baryon-pion scattering in the 1/N c expansion: Tree diagram cancellations

A new measurement of the ${\ensuremath{\Xi}}^{0}$ mass verifies the accuracy of the Coleman-Glashow relation at the level predicted by the ${1/N}_{c}$ expansion. Values for other baryon isospin mass splittings are updated, and continue to agree with the ${1/N}_{c}$ hierarchy.

https://digital.library.unt.edu/ark:/67531/metadc710573/m2/1/high_res_d/754871.pdf

Naturalness of the Coleman-Glashow mass relation in the 1/N c expansion: An update

Renormalization of the Standard Model Effective Field Theory from geometry

Large-N(c) QCD

The decay Δ + → py is studied in the 1/N c expansion of QCD. The ratio of the helicity amplitudes is determined to be A 3 / 2 /A 1 / 2 = √3 + O(1/N 2 c ). Equivalently, the ratio E2/M1 of the multipole amplitudes is predicted to be order 1/N 2 c .

Elizabeth Jenkins

Papers

Baryon-pion scattering in the 1/N c expansion: Tree diagram cancellations

Naturalness of the Coleman-Glashow mass relation in the 1/N c expansion: An update

Renormalization of the Standard Model Effective Field Theory from geometry

Large-N(c) QCD

Δ → Nγ in Large-Nc QCD