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Geng, L S

Publications and source records attributed to Geng, L S.

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Analysis of the LQCD results on the lowest-lying baryon masses in chiral perturbation theory

We review recent progress in the understanding of low-energy baryon structure by means of chiral perturbation theory. In particular, we discuss the application of this formalism to the description of the quark mass dependence of recent Lattice QCD results on the masses. We present the chiral extrapolation of those of the PACS-CS and LHP collaborations and we predictthe baryonic sigma-terms.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Low-lying even-parity meson resonances and spin-flavor symmetry

Based on a spin-flavor extension of chiral symmetry, a novel s-wave meson-meson interaction involving members of the {rho} nonet and of the {pi} octet is introduced, and its predictions are analyzed. The starting point is the SU(6) version of the SU(3)-flavor Weinberg-Tomozawa Lagrangian. SU(6) symmetry-breaking terms are then included to account for the physical meson masses and decay constants in a way that preserves (broken) chiral symmetry. Next, the T-matrix amplitudes are obtained by solving the Bethe-Salpeter equation in a coupled-channel scheme, and the poles are identified with their possible Particle Data Group counterparts. It is shown that most of the low-lying even-parity Particle Data Group meson resonances, especially in the J{sup P}=0{sup +} and 1{sup +} sectors, can be classified according to multiplets of SU(6). The f{sub 0}(1500), f{sub 1}(1420), and some 0{sup +}(2{sup ++}) resonances cannot be accommodated within this scheme, and thus they would be clear candidates to be glueballs or hybrids. Finally, we predict the existence of five exotic resonances (I{>=}3/2 and/or |Y|=2) with masses in the range of 1.4-1.6 GeV, which would complete the 27{sub 1}, 10{sub 3}, and 10{sub 3}* multiplets of SU(3) x SU(2).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

The f{sub 0}(1370), f{sub 0}(1710), f{sub 2}(1270), f{sub 2}{sup '}(1525), and K{sub 2}{sup *}(1430) as dynamically generated states from vector meson-vector meson interaction

We report on some recent developments in understanding the nature of the low-lying mesonic resonances f{sub 0}(1370), f{sub 0}(1710), f{sub 2}(1270), f{sub 2}{sup '}(1525), and K{sub 2}*(1430). In particular we show that these five resonances can be dynamically generated from vector meson-vector meson interaction in a coupled-channel unitary approach, which utilizes the phenomenologically very successful hidden-gauge Lagrangians to produce the interaction kernel between two vector mesons, which is then unitarized by the Bethe-Salpeter-equation method. The data on the strong decay branching ratios, total decay widths, and radiative decay widths of these five states, and on related J/{psi} decay processes can all be well described by such an approach. We also make predictions, compare them with the results of earlier studies, and highlight observables that if measured can be used to distinguish different pictures of these resonances.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Analysis of the LQCD results on the lowest-lying baryon masses in chiral perturbation theory

We review recent progress in the understanding of low-energy baryon structure by means of chiral perturbation theory. In particular, we discuss the application of this formalism to the description of the quark mass dependence of recent Lattice QCD results on the masses. We present the chiral extrapolation of those of the PACS-CS and LHP collaborations and we predictthe baryonic sigma-terms.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Lowest-lying baryon masses in covariant SU(3)-flavor chiral perturbation theory

We present an analysis of the baryon-octet and -decuplet masses using covariant SU(3)-flavor chiral perturbation theory up to next-to-leading order. Besides the description of the physical masses we address the problem of the lattice QCD extrapolation. Using the PACS-CS Collaboration data we show that a good description of the lattice points can be achieved at next-to-leading order with the covariant loop amplitudes and phenomenologically determined values for the meson-baryon couplings. Moreover, the extrapolation to the physical point up to this order is found to be better than the linear one given at leading-order by the Gell-Mann-Okubo approach. The importance that a reliable combination of lattice QCD and chiral perturbation theory may have for hadron phenomenology is emphasized with the prediction of the pion-baryon and strange-baryon sigma terms.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Low-energy interactions of Nambu-Goldstone bosons with D mesons in covariant chiral perturbation theory

We calculate the scattering lengths of Nambu-Goldstone bosons interacting with D mesons in a covariant formulation of chiral perturbation theory, which satisfies heavy-quark spin symmetry and analytical properties of loop amplitudes. We compare our results with previous studies performed using heavy-meson chiral perturbation theory and show that recoil corrections are sizable in most cases.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Vector meson-vector meson interaction and dynamically generated resonances

Using the local hidden gauge formalism for the vector meson-vector meson interaction within a unitary approach we find that 11 states get dynamically generated. Five of them are associated to the f{sub 0}(1370), f{sub 0}(1710), f{sub 2}(1270), f{sub 2}'(1525), and K{sub 2}*(1430) resonances, by comparing the mass, width, and decay pattern of these states with those of their experimental counterparts. At the same time we predict six other states with the quantum numbers of h{sub 1}, a{sub 0}, b{sub 1}, a{sub 2}, K{sub 0}*, and K{sub 1} which could be tested by future experiments.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗