scholarly journals The Sigma Term: Leading Non-Analytic Behaviour Of Decuplet Contributions

1994 ◽  
Vol 47 (1) ◽  
pp. 45 ◽  
Author(s):  
I Jameson ◽  
AA Rawlinson ◽  
AW Thomas
Keyword(s):  
Quark Mass ◽  
Mass Splitting ◽  
Analytic Structure ◽  
Nucleon Mass ◽  
Sigma Term ◽  
Pion Nucleon ◽  
Analytic Behaviour

We examine the analytic structure, in powers of the quark mass (m), of the chiral loop corrections to the pion-nucleon sigma term arising from coupling to the lowest mass baryon decuplet. The leading non-analytic term is found to go like m2 In(m/2a) (with a the delta-nucleon mass splitting), and to be quite significant numerically.

scholarly journals THE NUCLEON MASS AND PION-NUCLEON SIGMA TERM FROM A CHIRAL ANALYSIS OF Nf = 2 + 1 LATTICE QCD WORLD DATA

2014 ◽  
Vol 26 ◽  
pp. 1460089 ◽  
Author(s):  
L. ALVAREZ-RUSO ◽  
T. LEDWIG ◽  
M. J. VICENTE VACAS ◽  
J. MARTIN-CAMALICH
Keyword(s):  
Lattice Qcd ◽  
Degrees Of Freedom ◽  
Pion Mass ◽  
Nucleon Mass ◽  
A Value ◽  
Natural Size ◽  
Sigma Term ◽  
Pion Nucleon ◽  
Pion Mass Dependence ◽  
Energy Constants

Fits of the p4 covariant SU(2) baryon chiral perturbation theory to lattice QCD nucleon mass data from several collaborations for 2 and 2+1 flavors are presented. We consider contributions from explicit Δ(1232) degrees of freedom, finite volume and finite spacing corrections. We emphasize here on our Nf = 2 + 1 study. We obtain low-energy constants of natural size that are compatible with the rather linear pion-mass dependence of the nucleon mass observed in lattice QCD. We report a value of σπN = 41(5)(4) MeV in the 2 flavor case and σπN = 52(3)(8) MeV for 2+1 flavors.

scholarly journals Nucleon mass and pion-nucleon sigma term from a chiral analysis of lattice QCD world data

2014 ◽  
Vol 73 ◽  
pp. 04015 ◽  
Author(s):  
L. Alvarez-Ruso ◽  
T. Ledwig ◽  
J. Martin Camalich ◽  
M.J. Vicente Vacas
Keyword(s):  
Lattice Qcd ◽  
Chiral Analysis ◽  
Nucleon Mass ◽  
World Data ◽  
Sigma Term ◽  
Pion Nucleon

scholarly journals Nucleon mass splitting in the isospin medium

2014 ◽  
Vol 29 (29) ◽  
pp. 1450170 ◽  
Author(s):  
Bum-Hoon Lee ◽  
Shahin Mamedov ◽  
Chanyong Park
Keyword(s):  
Mass Splitting ◽  
Meson Mass ◽  
Nucleon Mass ◽  
Unitary Gauge ◽  
Gauge Fixing ◽  
Pion Nucleon ◽  
Charged Mesons

Using the AdS/CFT correspondence, we investigate a nucleon mass splitting and pion–nucleon coupling in the isospin medium. We find that there exists a nucleon mass splitting which is exactly given by the half of the meson mass splitting because nucleon has the half isospin charge of the charged mesons. In addition, we also investigate the pion–nucleon and four pion interactions which requires the modification of the known Abelian-type unitary gauge fixing because of the non-Abelian structure of the isospin medium. After finding the non-Abelian unitary gauge fixing, we find that in the isospin medium the couplings only for π0 π0 π+ π- and π0 π0π0 π0 of four pion interactions shift, while there is no pion–nucleon coupling splitting in spite of the nucleon's and meson's mass splittings.

scholarly journals Chiral Corrections for Lattice QCD

1991 ◽  
Vol 44 (3) ◽  
pp. 173 ◽  
Author(s):  
Anthony W Thomas
Keyword(s):  
Lattice Qcd ◽  
Quark Mass ◽  
Mass Splitting ◽  
Residual Error ◽  
Similar Amount ◽  
Nucleon Mass ◽  
Systematic Method ◽  
Lattice Size

We show that in the quenched approximation, lattice QCD calculations miss important corrections to the mass of hadrons. For example, we argue that the nucleon mass is overestimated by up to 30% while the nucleon-delta mass splitting is underestimated by a similar amount. As the quenched approximation is relaxed, the quark mass decreased and the lattice size increased, these errors should go away. A systematic method of monitoring the size of the residual error is suggested.

scholarly journals The nucleon mass and pion-nucleon sigma term from a chiral analysis ofNf= 2 lattice QCD world data

2014 ◽  
Vol 66 ◽  
pp. 06001
Author(s):  
L. Alvarez-Ruso ◽  
T. Ledwig ◽  
J. Martin Camalich ◽  
M. J. Vicente Vacas
Keyword(s):  
Lattice Qcd ◽  
Chiral Analysis ◽  
Nucleon Mass ◽  
World Data ◽  
Sigma Term ◽  
Pion Nucleon

scholarly journals Nucleon mass and pion-nucleon sigma term from a chiral analysis of lattice QCD data

2013 ◽  
Vol 88 (5) ◽  
Author(s):  
L. Alvarez-Ruso ◽  
T. Ledwig ◽  
J. Martin Camalich ◽  
M. J. Vicente-Vacas
Keyword(s):  
Lattice Qcd ◽  
Chiral Analysis ◽  
Nucleon Mass ◽  
Sigma Term ◽  
Pion Nucleon

Quark mass differences and isospin violation in the pion-nucleon coupling constants

1989 ◽  
Vol 39 (5) ◽  
pp. 2054-2056 ◽  
Author(s):  
Véronique Bernard ◽  
Ulf-G. Meissner
Keyword(s):  
Quark Mass ◽  
Coupling Constants ◽  
Isospin Violation ◽  
Pion Nucleon

Breaking scale symmetry and the pion-nucleon sigma-term

1974 ◽  
Vol 10 (18) ◽  
pp. 855-860
Author(s):  
T. Becheekawy ◽  
S. J. Hakim
Keyword(s):  
Sigma Term ◽  
Pion Nucleon ◽  
Breaking Scale
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