Related papers: Quenched Chiral Physics in Baryon Masses
The meson fields are simulated by quark operators and an effective chiral theory of mesons is presented. There are spontaneous chiral symmetry breaking and dynamical chiral symmetry breaking. Theoretical results agree with data well.
The relevance of chiral symmetry in baryons is highlighted in three examples in the nucleon spectroscopy and structure. The first one is the importance of chiral dynamics in understanding the Roper resonance. The second one is the role of…
Lattice QCD has generated a wealth of data in hadronic physics over the last two decades. Until relatively recently, most of this information has been within the "quenched approximation" where virtual quark--anti-quark pairs are neglected.…
Aiming at the link between confinement and chiral symmetry the Polyakov loop represented as a spectral sum of eigenvalues of the Dirac operator was subject of recent studies. We analyze the volume dependence as well as the continuum…
In the past year domain wall fermion simulations have moved from exploratory stages to the point where systematic effects can be studied with different gauge couplings, volumes, and lengths in the fifth dimension. Results are presented here…
The principal purpose of meson spectroscopy is to understand the confining force, which is generally assumed to be based on low-energy QCD. This is usually done in the context of quark models that ignore the dynamical effects of quark-pair…
We calculate electromagnetic properties of the decuplet baryons in quenched and partially quenched chiral perturbation theory. We work at next-to-leading order in the chiral expansion, leading order in the heavy baryon expansion, and obtain…
We present results of meson and baryon spectroscopy using the Chirally Improved Dirac operator on lattices of size 16**3 x 32 with two mass-degenerate light sea quarks. Three ensembles with pion masses of 322(5), 470(4) and 525(7) MeV and…
It is shown that the principal pattern in baryon spectroscopy, which is associated with the flavor-spin dependent hyperfine interaction, is due to the spontaneous breaking of chiral symmetry in QCD and persists in the chiral limit. All…
We present the inconsistencies which arise in quenched QCD in $\Delta I=1/2$ non-leptonic kaon decays using chiral perturbation theory (ChPT) to one loop. In particular we discuss how the lack of unitarity of the quenched theory invalidates…
We discuss how to formulate a staggered chiral perturbation theory. This amounts to a generalization of the Lee-Sharpe Lagrangian to include more than one flavor (i.e. multiple staggered fields), which turns out to be nontrivial. One loop…
The utility of chiral effective field theory, constructed in a manner in which loop contributions are suppressed as one moves outside the power-counting regime, is explored for baryon magnetic moments. Opportunities for the study of…
In this paper we use one-loop chiral perturbation theory in order to compare lattice computations of the K+ to pi+ pi0 decay amplitude with the experimental value. This makes it possible to investigate three systematic effects that plague…
Quenched lattice QCD simulations and quenched chiral perturbation theory are used together for this study of strangeness in the nucleon. Dependences of the matrix elements on strange quark mass, valence quark mass and momentum transfer are…
It is shown that the principal pattern in baryon spectroscopy, which is associated with the flavor-spin dependent hyperfine interaction, is due to the spontaneous breaking of chiral symmetry in QCD and thus cannot be addressed by chiral…
Quenched chiral perturbation theory is extended to include heavy-light mesons. Non-analytic corrections to the decay constants, Isgur-Wise function and masses and mixing of heavy mesons are then computed. The results are used to estimate…
We investigate light hadron spectroscopy with an improved quenched staggered quark action. We compare the results obtained with an improved gauge plus an improved quark action, an improved gauge plus standard quark action, and the standard…
This paper summarizes the recent calculations of the masses and decay constants of the pseudoscalar mesons at the two-loop level, or NNLO, in Partially Quenched Chiral Perturbation Theory (PQxPT). Possible applications include chiral…
We present results for masses of excited baryons from a quenched calculation with Chirally Improved quarks at pion masses down to 350 MeV. Our analysis of the correlators is based on the variational method. In order to provide a large basis…
We report the final results of the CP-PACS calculation for the quenched light hadron spectrum with the Wilson quark action. Our data support the presence of quenched chiral singularities, and this motivates us to use mass formulae based on…