Search results for "chiral [model]"
showing 10 items of 83 documents
Photoproduction of scalar mesons on protons and nuclei
1999
We study the photoproduction of scalar mesons close to the threshold of f_0(980) and a_0(980) using a unitary chiral model. Peaks for both resonances show up in the invariant mass distributions of pairs of pseudoscalar mesons. A discussion is made on the photoproduction of these resonances in nuclei, which can shed light on their nature, a subject of continuous debate.
Exploring the D* rho system within QCD sum rules
2013
We present a study of the D* rho system made by using the method of QCD sum rules to determine the mass of possible resonances generated in the same system. Using isospin and spin projectors, we investigate the different configurations and obtain evidences for three D* mesons with isospin I = 1/2, spin S = 0, 1, 2 and with masses 2500 +/- 67, 2523 +/- 60, and 2439 +/- 119 MeV, respectively. The last state can be associated with D-2*(2460) ( spin 2) listed by the Particle Data Group, while one of the first two might be related to D* (2640), with unknown spin parity. In the case of I = 3/2 we also find evidences of three states with spin 0, 1, and 2, respectively, with masses 2467 +/- 82, 242…
Axial resonances in the open and hidden charm sectors
2007
13 pages, 2 figures.-- PACS nrs.: 11.10.St, 11.80.Gw, 12.39.Hg, 12.39.Fe.-- ISI Article Identifier: 000249271600001.-- ArXiv pre-print available at: http://arxiv.org/abs/0704.2314
Latest Results for the Antikaon-Nucleon Optical Potential
2010
The key question of this letter is whether the K-nucleus optical potential is deep, as it is prefered by the phenomenological fits to kaonic atoms data, or shallow, as it comes out from unitary chiral model calculations. The current experimental situation is reviewed.
Oblique S and T Constraints on Electroweak Strongly-Coupled Models with a Light Higgs
2014
Using a general effective Lagrangian implementing the chiral symmetry breaking SU(2) L ⊗ SU(2) R → SU(2) L+R , we present a one-loop calculation of the oblique S and T parameters within electroweak strongly-coupled models with a light scalar. Imposing a proper ultraviolet behaviour, we determine S and T at next-to-leading order in terms of a few resonance parameters. The constraints from the global fit to electroweak precision data force the massive vector and axial-vector states to be heavy, with masses above the TeV scale, and suggest that the W + W − and ZZ couplings of the Higgs-like scalar should be close to the Standard Model value. Our findings are generic, since they only rely on so…
Towards a determination of the chiral couplings at NLO in 1/N-C: L-8(r)(μ) and C-38(r)(μ)
2007
14 pages.-- ISI Article Identifier: 000244120200039.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0610290
V-us determination from hyperon semileptonic decays
2005
16 páginas, 9 tablas.-- arXiv:hep-ph/0509045v2
Crystal structure of (1S,2R,4S)-1-[(morpholin-4-yl)methyl]-4-(prop-1-en-2-yl)cyclohexane-1,2-diol
2014
Besides intramolecular O—H⋯N hydrogen bonds, the crystal structure displays intermolecular O—H⋯O and C—H⋯O hydrogen bonds linking the molecules into undulating layers parallel to the (01) plane.
Low-energy couplings of QCD from topological zero-mode wave functions
2003
By matching 1/m^2 divergences in finite-volume two-point correlation functions of the scalar or pseudoscalar densities with those obtained in chiral perturbation theory, we derive a relation between the Dirac operator zero-mode eigenfunctions at fixed non-trivial topology and the low-energy constants of QCD. We investigate the feasibility of using this relation to extract the pion decay constant, by computing the zero-mode correlation functions on the lattice in the quenched approximation and comparing them with the corresponding expressions in quenched chiral perturbation theory.
Towards a consistent estimate of the chiral low-energy constants
2006
Guided by the large-N_C limit of QCD, we construct the most general chiral resonance Lagrangian that can generate chiral low-energy constants up to O(p^6). By integrating out the resonance fields, the low-energy constants are parametrized in terms of resonance masses and couplings. Information on those couplings and on the low-energy constants can be extracted by analysing QCD Green functions of currents both for large and small momenta. The chiral resonance theory generates Green functions that interpolate between QCD and chiral perturbation theory. As specific examples we consider the VAP and SPP Green functions.