skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Nc dependencies of baryon masses: Analysis with Lattice QCD and Effective Theory

Abstract

Baryon masses at varying values of Nc and light quark masses are studied with Lattice QCD and the results are analyzed in a low energy effective theory based on a combined framework of the 1/Nc and Heavy Baryon Chiral Perturbation Theory expansions. Lattice QCD results for Nc=3, 5 and 7 obtained in quenched calculations, as well as results for unquenched calculations for Nc=3, are used for the analysis. The results are consistent with a previous analysis of Nc=3 LQCD results, and in addition permit the determination of sub-leading in 1/Nc effects in the spin-flavor singlet component of the baryon masses as well as in the hyperfine splittings.

Authors:
 [1];  [2];  [1]
  1. JLAB
  2. University of Colorado
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1136853
Report Number(s):
JLAB-THY-14-1866; DOE/OR/23177-3040; arXiv:1404.2301
FG02-04ER41290; NSF PHY-0855789; NSF PHY-1307413
DOE Contract Number:
AC05-06OR23177
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review D; Journal Volume: 90; Journal Issue: 01
Country of Publication:
United States
Language:
English

Citation Formats

Calle Cordon, Alvaro C., DeGrand, Thomas A., and Goity, Jose L.. The Nc dependencies of baryon masses: Analysis with Lattice QCD and Effective Theory. United States: N. p., 2014. Web. doi:10.1103/PhysRevD.90.014505.
Calle Cordon, Alvaro C., DeGrand, Thomas A., & Goity, Jose L.. The Nc dependencies of baryon masses: Analysis with Lattice QCD and Effective Theory. United States. doi:10.1103/PhysRevD.90.014505.
Calle Cordon, Alvaro C., DeGrand, Thomas A., and Goity, Jose L.. 2014. "The Nc dependencies of baryon masses: Analysis with Lattice QCD and Effective Theory". United States. doi:10.1103/PhysRevD.90.014505. https://www.osti.gov/servlets/purl/1136853.
@article{osti_1136853,
title = {The Nc dependencies of baryon masses: Analysis with Lattice QCD and Effective Theory},
author = {Calle Cordon, Alvaro C. and DeGrand, Thomas A. and Goity, Jose L.},
abstractNote = {Baryon masses at varying values of Nc and light quark masses are studied with Lattice QCD and the results are analyzed in a low energy effective theory based on a combined framework of the 1/Nc and Heavy Baryon Chiral Perturbation Theory expansions. Lattice QCD results for Nc=3, 5 and 7 obtained in quenched calculations, as well as results for unquenched calculations for Nc=3, are used for the analysis. The results are consistent with a previous analysis of Nc=3 LQCD results, and in addition permit the determination of sub-leading in 1/Nc effects in the spin-flavor singlet component of the baryon masses as well as in the hyperfine splittings.},
doi = {10.1103/PhysRevD.90.014505},
journal = {Physical Review D},
number = 01,
volume = 90,
place = {United States},
year = 2014,
month = 7
}
  • We investigate the quark mass dependence of baryon masses in 2+1 flavor lattice QCD using SU(3) heavy baryon chiral perturbation theory up to one-loop order. The baryon mass data used for the analyses are obtained for the degenerate up-down quark mass of 3 to 24 MeV and two choices of the strange quark mass around the physical value. We find that the SU(3) chiral expansion fails to describe both the octet and the decuplet baryon data if phenomenological values are employed for the meson-baryon couplings. The SU(2) case is also examined for the nucleon. We observe that higher order termsmore » are controlled only around the physical point. We also evaluate finite size effects using SU(3) heavy baryon chiral perturbation theory, finding small values of order 1% even at the physical point.« less
  • 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.
  • 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.
  • The baryon electromagnetic form factors are expressed in terms of two-dimensional densities describing the distribution of charge and magnetization in transverse space at fixed light-front time. In this paper, we calculate the transverse densities of the spin-1/2 flavor-octet baryons at peripheral distances b=O(Mmore » $$-1\atop{π}$$) using methods of relativistic chiral effective field theory (χ EFT) and dispersion analysis. The densities are represented as dispersive integrals over the imaginary parts of the form factors in the timelike region (spectral functions). The isovector spectral functions on the two-pion cut t > 4 M$$2\atop{π}$$ are calculated using relativistic χEFT including octet and decuplet baryons. The χEFT calculations are extended into the ρ meson mass region using an N/D method that incorporates the pion electromagnetic form factor data. The isoscalar spectral functions are modeled by vector meson poles. We compute the peripheral charge and magnetization densities in the octet baryon states, estimate the uncertainties, and determine the quark flavor decomposition. Finally, the approach can be extended to baryon form factors of other operators and the moments of generalized parton distributions.« less