scholarly journals Strong-isospin violation in the neutron–proton mass difference from fully-dynamical lattice QCD and PQQCD

2007 ◽  
Vol 768 (1-2) ◽  
pp. 38-50 ◽  
Author(s):  
Silas R. Beane ◽  
Kostas Orginos ◽  
Martin J. Savage
Keyword(s):  
Lattice Qcd ◽  
Mass Difference ◽  
Isospin Violation ◽  
Proton Mass ◽  
Dynamical Lattice

scholarly journals Neutron-Proton Mass Difference in Nuclear Matter and in Finite Nuclei and the Nolen-Schiffer Anomaly

2010 ◽  
Vol 3 ◽  
pp. 06008 ◽  
Author(s):  
U.-G. Meißner ◽  
A.M. Rakhimov ◽  
A. Wirzba ◽  
U.T. Yakhshiev
Keyword(s):  
Nuclear Matter ◽  
Mass Difference ◽  
Proton Mass ◽  
Finite Nuclei

Electromagnetic neutron-proton mass difference in the Skyrme model

1987 ◽  
Vol 189 (3) ◽  
pp. 343-346 ◽  
Author(s):  
Abdul Ebrahim ◽  
Mustafa Savci
Keyword(s):  
Mass Difference ◽  
Skyrme Model ◽  
Proton Mass

scholarly journals Calculation of 〈p‖u¯u-d¯d‖p〉 from QCD sum rules and the neutron-proton mass difference

1995 ◽  
Vol 51 (7) ◽  
pp. 3688-3696 ◽  
Author(s):  
Xuemin Jin ◽  
Marina Nielsen ◽  
J. Pasupathy
Keyword(s):  
Sum Rules ◽  
Mass Difference ◽  
Qcd Sum Rules ◽  
Proton Mass

scholarly journals A note on the neutron–proton mass difference

Physics Today ◽  
2015 ◽  
Vol 68 (10) ◽  
pp. 12-12 ◽  
Author(s):  
Gordon Kane
Keyword(s):  
Mass Difference ◽  
Proton Mass

EXACT DYNAMICAL EIGHTFOLD WAY BARYON SPECTRUM AND CONFINEMENT IN STRONGLY COUPLED LATTICE QCD

2009 ◽  
Vol 24 (16n17) ◽  
pp. 3053-3072 ◽  
Author(s):  
PAULO A. FARIA DA VEIGA ◽  
MICHAEL O'CARROLL
Keyword(s):  
Lattice Qcd ◽  
Rotational Symmetry ◽  
Mass Difference ◽  
Dispersion Curves ◽  
Momentum Spectrum ◽  
Functional Integral ◽  
Strong Coupling Regime ◽  
Partial Restoration ◽  
Baryon Spectrum ◽  
The Masses

We obtain from the quark–gluon dynamics the eightfold way baryon spectrum exactly in an imaginary time functional integral formulation of 3+1 lattice QCD with Wilson's action in the strong coupling regime (small hopping parameter 0 < κ ≪ 1 and much smaller plaquette coupling [Formula: see text]). The model has SU(3)c local gauge and global SU(3)f flavor symmetries. A decoupling of the hyperplane method naturally unveils the form of the baryon composite fields. In the subspace of the physical Hilbert space of vectors with an odd number of quarks, the baryons are associated with isolated dispersion curves in the energy–momentum spectrum. Spectral representations are derived for the two-baryon correlations, which allow us to detect the energy–momentum spectrum and particles as complex momentum space singularities. The spin 1/2 octet and spin 3/2 decuplet baryons have asymptotic mass -3ln κ and for each baryon there is an antibaryon with identical spectral properties. An auxiliary function method is used to obtain convergent expansions for the masses after subtracting the singular part -3ln κ. The nonsingular part of the mass is analytic in κ and β, i.e. the expansions are controlled to all orders. For β = 0, all the masses have the form M = -3ln κ - 3κ3/4 + κ6r(κ), with r(κ) real analytic. Although we have no Lorentz symmetry in our lattice model, we show that there is a partial restoration of the continuous rotational symmetry at zero spatial momentum, which implies that for all members of the octet (decuplet) r(κ) is the same. So, there is no mass splitting within the octet and within the decuplet. However, there is an octet–decuplet mass difference of [Formula: see text] at β = 0; the splitting persists for β ≠ 0. We also obtain the (anti)baryon dispersion curves which admit the representation [Formula: see text], where [Formula: see text] and [Formula: see text] is of [Formula: see text]. For the octet, [Formula: see text] is jointly analytic in κ and in each pj, for small [Formula: see text]. A new local symmetry, which we call spin flip, is used to establish constraints for the matrix-valued two-baryon correlation and show that all the octet dispersion curves are the same and that the four decuplet dispersion curves are pairwise-identical and depend only on the modulus of the spin z-component. Using a correlation subtraction method we show that the spectrum generated by the baryon and antibaryon fields is the only spectrum, in the odd quark subspace of physical states, up to near the baryon–meson threshold of ≈ -5ln κ. Combining this result with a similar result for the mesons, with mass ≈ -2ln κ, shows that the only spectrum in the entire space of states, up to near the two-meson threshold of ≈ -4ln κ, is generated by the eightfold way hadrons. Hence, for 0 < κ ≪ β ≪ 1, we have shown confinement up to near this threshold.

Neutron-proton mass difference

1962 ◽  
Vol 26 (5) ◽  
pp. 1063-1065 ◽  
Author(s):  
L. K. Pande
Keyword(s):  
Mass Difference ◽  
Proton Mass

CHARGE SYMMETRY BREAKING IN pn → dπ0

2011 ◽  
Vol 26 (03n04) ◽  
pp. 592-594
Author(s):  
ARSENIY A. FILIN
Keyword(s):  
Symmetry Breaking ◽  
Cross Section ◽  
Mass Difference ◽  
Leading Order ◽  
Charge Symmetry Breaking ◽  
Chiral Perturbation ◽  
Charge Symmetry ◽  
Sum Rule ◽  
Proton Mass ◽  
Complete Calculation

We study charge symmetry breaking (CSB) in the reaction pn → dπ0. CSB manifests itself in a forward-backward asymmetry of the differential cross section measured recently at TRIUMF. A complete calculation of CSB effects at leading order in chiral perturbation theory is performed. A new leading-order operator is included. This allows us to extract the strong contribution to the neutron-proton mass difference from the analysis. The value obtained is consistent with the result of Gasser and Leutwyler based on the Cottingham sum rule and with an extraction from lattice QCD.

Neutron-proton mass difference in the chiral solitonic bag model

1987 ◽  
Vol 36 (11) ◽  
pp. 3443-3449 ◽  
Author(s):  
M. Durgut ◽  
N. K. Pak ◽  
T. Yilmaz
Keyword(s):  
Mass Difference ◽  
Bag Model ◽  
Proton Mass

scholarly journals Progress in resolving charge symmetry violation in nucleon structure

2014 ◽  
Vol 23 (07) ◽  
pp. 1461010
Author(s):  
R. D. Young ◽  
P. E. Shanahan ◽  
A. W. Thomas
Keyword(s):  
Lattice Qcd ◽  
Recent Work ◽  
Mass Difference ◽  
Baryon Octet ◽  
Nucleon Structure ◽  
Symmetry Violation ◽  
Charge Symmetry ◽  
Parton Distributions

Recent work unambiguously resolves the level of charge symmetry violation in moments of parton distributions using (2 + 1)-flavor lattice QCD. We introduce the methods used for that analysis by applying them to determine the strong contribution to the proton–neutron mass difference. We also summarize related work which reveals that the fraction of baryon spin which is carried by the quarks is in fact structure-dependent rather than universal across the baryon octet.

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