Baryon-baryon bound states in strongly coupled lattice QCD

2007 ◽  
Vol 75 (7) ◽  
Author(s):  
Paulo A. Faria da Veiga ◽  
Michael O’Carroll
Keyword(s):  
Lattice Qcd ◽  
Bound States ◽  
Strongly Coupled

Meson-meson bound states in a(2+1)-dimensional strongly coupled lattice QCD model

2004 ◽  
Vol 69 (9) ◽  
Author(s):  
Paulo A. Faria da Veiga ◽  
Michael O’Carroll ◽  
Antônio Francisco Neto
Keyword(s):  
Lattice Qcd ◽  
Bound States ◽  
Strongly Coupled

ON THE ABSENCE OF PENTAQUARK STATES FROM DYNAMICS IN STRONGLY COUPLED LATTICE QCD

2011 ◽  
Vol 26 (01) ◽  
pp. 71-133 ◽  
Author(s):  
PAULO A. FARIA DA VEIGA ◽  
MICHAEL O'CARROLL ◽  
ANTÔNIO FRANCISCO NETO ◽  
PETRUS H. R. DOS ANJOS
Keyword(s):  
Lattice Qcd ◽  
Bound States ◽  
Threshold Value ◽  
Negative Energy ◽  
Functional Integral ◽  
Ladder Approximation ◽  
Exchange Potential ◽  
Strong Coupling Regime ◽  
Strongly Coupled ◽  
Spinless Case

We consider an imaginary time functional integral formulation of a two-flavor, 3+1 lattice QCD model with Wilson's action and in the strong coupling regime (with a small hopping parameter, κ > 0, and a much smaller plaquette coupling, [Formula: see text], so that the quarks and glueballs are heavy). The model has local SU (3)c gauge and global SU (2)f flavor symmetries, and incorporates the corresponding part of the eightfold way particles: baryons (mesons) of asymptotic mass ≈-3 ln κ(≈-2 ln κ). We search for pentaquark states as meson–baryon bound states in the energy–momentum spectrum of the model, using a lattice Bethe–Salpeter equation. This equation is solved within a ladder approximation, given by the lowest nonvanishing order in κ and β of the Bethe–Salpeter kernel. It includes order κ2 contributions with a [Formula: see text] exchange potential together with a contribution that is a local-in-space, energy-dependent potential. The attractive or repulsive nature of the exchange interaction depends on the spin of the meson–baryon states. The Bethe–Salpeter equation presents integrable singularities, forcing the couplings to be above a threshold value for the meson and the baryon to bind in a pentaquark. We analyzed all the total isospin sectors, I = 1/2, 3/2, 5/2, for the system. For all I, the net attraction resulting from the two sources of interaction is not strong enough for the meson and the baryon to bind. Thus, within our approximation, these pentaquark states are not present up to near the free meson–baryon energy threshold of ≈-5 ln κ. This result is to be contrasted with the spinless case for which our method detects meson–baryon bound states, as well as for Yukawa effective baryon and meson field models. A physical interpretation of our results emerges from an approximate correspondence between meson–baryon bound states and negative energy states of a one-particle lattice Schrödinger Hamiltonian.

Analytic Binding Energies for Two-Baryon Bound States in 2 + 1 Strongly Coupled Lattice QCD With Two-Flavors

2013 ◽  
Vol 321 (1) ◽  
pp. 249-282 ◽  
Author(s):  
Michael O’Carroll ◽  
Paulo A. Faria da Veiga ◽  
Antônio Francisco Neto
Keyword(s):  
Lattice Qcd ◽  
Bound States ◽  
Binding Energies ◽  
Strongly Coupled

scholarly journals Isospin-1/2 Dπ scattering and the lightest $$ {D}_0^{\ast } $$ resonance from lattice QCD

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Luke Gayer ◽  
Nicolas Lang ◽  
Sinéad M. Ryan ◽  
David Tims ◽  
Christopher E. Thomas ◽  
...  
Keyword(s):  
Scattering Amplitudes ◽  
Lattice Qcd ◽  
Quark Mass ◽  
Light Quark ◽  
Energy Levels ◽  
Experimental Result ◽  
Infinite Volume ◽  
Resonance Pole ◽  
Strongly Coupled ◽  
Light Quark Mass

Abstract Isospin-1/2 Dπ scattering amplitudes are computed using lattice QCD, working in a single volume of approximately (3.6 fm)3 and with a light quark mass corresponding to mπ ≈ 239 MeV. The spectrum of the elastic Dπ energy region is computed yielding 20 energy levels. Using the Lüscher finite-volume quantisation condition, these energies are translated into constraints on the infinite-volume scattering amplitudes and hence enable us to map out the energy dependence of elastic Dπ scattering. By analytically continuing a range of scattering amplitudes, a $$ {D}_0^{\ast } $$ D 0 ∗ resonance pole is consistently found strongly coupled to the S-wave Dπ channel, with a mass m ≈ 2200 MeV and a width Γ ≈ 400 MeV. Combined with earlier work investigating the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ , and $$ {D}_0^{\ast } $$ D 0 ∗ with heavier light quarks, similar couplings between each of these scalar states and their relevant meson-meson scattering channels are determined. The mass of the $$ {D}_0^{\ast } $$ D 0 ∗ is consistently found well below that of the $$ {D}_{s0}^{\ast } $$ D s 0 ∗ , in contrast to the currently reported experimental result.

Dynamical eightfold way mesons in strongly coupled lattice QCD

2008 ◽  
Vol 77 (5) ◽  
Author(s):  
Antônio Francisco Neto ◽  
Michael O’Carroll ◽  
Paulo A. Faria da Veiga
Keyword(s):  
Lattice Qcd ◽  
Strongly Coupled

scholarly journals The critical points of strongly coupled lattice QCD at nonzero chemical potential

1997 ◽  
Vol 56 (11) ◽  
pp. 7063-7072 ◽  
Author(s):  
Ian M. Barbour ◽  
Susan E. Morrison ◽  
Elyakum G. Klepfish ◽  
John B. Kogut ◽  
Maria-Paola Lombardo
Keyword(s):  
Lattice Qcd ◽  
Critical Points ◽  
Chemical Potential ◽  
Strongly Coupled

scholarly journals Proximity effect in a two-dimensional electron gas coupled to a thin superconducting layer

2018 ◽  
Vol 9 ◽  
pp. 1263-1271 ◽  
Author(s):  
Christopher Reeg ◽  
Daniel Loss ◽  
Jelena Klinovaja
Keyword(s):  
Bound States ◽  
Topological Phase ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Electron Gases ◽  
Band Shift ◽  
Superconducting Layer ◽  
Strongly Coupled ◽  
Semiconducting Material ◽  
Dimensional Electron Gas

There have recently been several experiments studying induced superconductivity in semiconducting two-dimensional electron gases that are strongly coupled to thin superconducting layers, as well as probing possible topological phases supporting Majorana bound states in such setups. We show that a large band shift is induced in the semiconductor by the superconductor in this geometry, thus making it challenging to realize a topological phase. Additionally, we show that while increasing the thickness of the superconducting layer reduces the magnitude of the band shift, it also leads to a more significant renormalization of the semiconducting material parameters and does not reduce the challenge of tuning into a topological phase.

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