scholarly journals Lattice QCD with 2+1 Flavors and Open Boundaries: First Results of the Baryon Spectrum

2015 ◽  
Author(s):  
Wolfgang Soeldner
Keyword(s):  
Lattice Qcd ◽  
Baryon Spectrum ◽  
Open Boundaries ◽  
First Results

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.

scholarly journals Charmed baryon spectrum from lattice QCD near the physical point

2020 ◽  
Vol 102 (5) ◽  
Author(s):  
H. Bahtiyar ◽  
K. U. Can ◽  
G. Erkol ◽  
P. Gubler ◽  
M. Oka ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Physical Point ◽  
Charmed Baryon ◽  
Baryon Spectrum

scholarly journals First results for theΔI = 12 amplitude in K decays with quenched lattice QCD and Wilson fermions

1988 ◽  
Vol 211 (1-2) ◽  
pp. 139-145 ◽  
Author(s):  
M.B. Gavela ◽  
L. Maiani ◽  
S. Petrarca ◽  
G. Martnelli ◽  
O. Pène
Keyword(s):  
Lattice Qcd ◽  
First Results ◽  
Wilson Fermions

ISOSPIN–SPIN INTERCHANGE SYMMETRY AND TWO-BARYON BOUND STATES IN (3+1)-DIMENSIONAL LATTICE QCD WITH TWO-FLAVORS AND STRONG COUPLING

2011 ◽  
Vol 26 (25) ◽  
pp. 4387-4404
Author(s):  
PAULO A. FARIA DA VEIGA ◽  
MICHAEL O'CARROLL ◽  
ANTÔNIO FRANCISCO NETO
Keyword(s):  
Binding Energy ◽  
Lattice Qcd ◽  
Strong Coupling ◽  
Bound States ◽  
Spin Symmetry ◽  
Exchange Potential ◽  
Strong Coupling Regime ◽  
Spectral Structure ◽  
Lattice Action ◽  
Baryon Spectrum

We determine two-baryon bound states in a 3+1 lattice QCD model with improved Wilson action and two flavors. We work in the strong coupling regime: small hopping parameter κ > 0 and much smaller plaquette coupling β > 0. In this regime, it is known that the low-lying energy–momentum spectrum is comprised of baryons and mesons with asymptotic masses -3 ln κ and -2 ln κ, respectively. We show that the dominant baryon–baryon interaction is an order κ2 space-range-one [Formula: see text]-exchange potential. We also show that this interaction has an important and novel isospin–spin interchange symmetry relating the various possible bound states, and then governing the two-baryon spectral structure. Letting S(I) denote the total spin (total isospin) of the two-baryon bound states, S, I = 0, 1, 2, 3, we find bound states with asymptotic binding energy κ2/4, for I+S = 1, 3, and 4 (here, with I = S = 2); κ2/12, for I+S = 0, 2, 4 and 3 (here, with I = 1, 2). In particular, we show that the two-baryon spectrum contains deuteron (I = 0), diproton (I = 1) and dineutron (I = 1)-like bound states. Using the isospin–spin symmetry, we can circumvent the lack of spin symmetry of the lattice action and show they all have the same asymptotic binding energy, namely κ2/4. Our analysis uses convenient two and four-baryon correlations, their spectral representations and a lattice Bethe–Salpeter equation, which is solved in a ladder approximation. For the isospin, spin part of the interaction, we obtain a permanent representation which describes the interaction of the individual spins and isospins of the quarks of one baryon with those of the other baryon.

scholarly journals Negative-parity baryon spectrum in quenched anisotropic lattice QCD

2003 ◽  
Vol 68 (9) ◽  
Author(s):  
Y. Nemoto ◽  
N. Nakajima ◽  
H. Matsufuru ◽  
H. Suganuma
Keyword(s):  
Lattice Qcd ◽  
Negative Parity ◽  
Baryon Spectrum ◽  
Anisotropic Lattice
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