On the question of quark confinement in the Abelian U(1)QED gauge interaction

If we approximate light quarks as massless and apply the Schwinger confinement mechanism to light quarks,we will reach the conclusion that a light quark and its antiquark will be confined as a boson in the Abelian U(1)QED gauge interaction in(1+1)D,as in an open string.From the work of Coleman,Jackiw,and Susskind,we can infer further that the Schwinger confinement mechanism persists even for massive quarks in(1+1)D.Could such a QED-confined one-dimensional open string in(1+1)D be the idealization of a flux tube in the physical world in(3+1)D,similar to the case of QCD-confined open string?If so,the QED-confined bosons may show up as neutral QED mesons in the mass region of many tens of MeV[Phys.Rev.C 81,064903(2010)&J.High Energy Phys.2020(8),165(2020)].Is it ever possible that a quark and an antiquark be produced and interact in QED alone to form a confined QED meson?Is there any experimental evidence for the existence of a QED meson(or QED mesons)?The observations of the anomalous soft photons,the X17 particle,and the E38 particle suggest that they may bear the experimental evidence for the existence of such QED mesons.Further confirmation and investigations on the X17 and E38 particles will shed definitive light on the question of quark confinement in QED in(3+1)D.Implications of quark confinement in the QED interaction are discussed.

Addendum： Quark Confinement, New Cosmic Expansion and General Yang-Mills Symmetry （J. P. Hsu, Chin. Phys. C, 41（1）： 015101 （2017））

The force between a gigantic sphere with baryon galaxies exerted on an idealized point-like supernova is given by Fcbf = F1 in Eq. （40） of the original paper. We can generalized the point-like supernova to a sphere with a radius Rs and a constant mass density Ps.

Quark confinement, new cosmic expansion and general Yang-Mills symmetry

We discuss a unified model of quark confinement and new cosmic expansion with linear potentials based on a general（SU3）color×（U1）baryon symmetry. The phase functions in the usual gauge transformations are generalized to new ‘action integrals＇. The general Yang-Mills transformations have group properties and reduce to usual gauge transformations in special cases. Both quarks and ‘gauge bosons＇ are permanently confined by linear potentials. In this unified model of particle-cosmology, physics in the largest cosmos and that in the smallest quark system appear to both be dictated by the general Yang-Mills symmetry and characterized by a universal length. The basic force between two baryons is independent of distance. However, the cosmic repulsive force exerted on a baryonic supernova by a uniform sphere of galaxies is proportional to the distance from the center of the sphere. The new general YangMills field may give a field-theoretic explanation of the accelerated cosmic expansion. The prediction could be tested experimentally by measuring the frequency shifts of supernovae at different distances.

Higgs-Like Mechanism by Confinement of Quarks in a Chemical Non-Equilibrium Model

A chemical non-equilibrium equation for binding of massless quarks to antiquarks, combined with the spatial correlations occurring in the condensation process, yields a density dependent form of the double-well potential in the electroweak theory. The Higgs boson acquires mass, valence quarks emerge and antiparticles become suppressed when the system relaxes and symmetry breaks down. The hitherto unknown dimensionless coupling parameter to the superconductor-like potential becomes a re-gulator of the quark-antiquark asymmetry. Only a small amount of quarks become “visible”—the valence quarks, which are 13% of the total sum of all quarks and antiquarks—suggesting that the quarks-antiquark pair components of the becoming quark-antiquark sea play the role of dark matter. When quark-masses are in-weighted, this number approaches the observed ratio between ordinary matter and the sum of ordinary and dark matter. The model also provides a chemical non-equilibrium explanation for the information loss in black holes, such as of baryon number.

Tetraquark and Pentaquark Systems in Lattice QCD

We study multi-quark systems in lattice QCD. First, we revisit and summarize our accurate mass measurements of low-lying 5Q states with J = 1/2 and I = 0 in both positive- and negative-parity channels in anisotropic lattice QCD. The lowest positive-parity 5Q state is found to have a large mass of about 2.24 GeV after the chiral extrapolation. To single out the compact 5Q state from NK scattering states, we use the hybrid boundary condition (HBC), and find no evidence of the compact 5Q state below 1.75 GeV in the negative-parity channel. Second, we study the multi-quark potential in lattice QCD to clarify the inter-quark interaction in multi-quark systems. The 5Q potential V5Q for the QQ--QQ system is found to be well described by the “OGE Coulomb plus multi-Y Ansatz”: The sum of the one-gluon-exchange (OGE) Coulomb term and the multi-Y-type linear term based on the flux-tube picture. The 4Q potential V4Q for the QQ- system is also described by the OGE Coulomb plus multi-Y Ansatz, when QQ and are well separated. The 4Q system is described as a “two-meson” state with disconnected flux tubes, when the nearest quark and antiquark pair are spatially close. We observe a lattice-QCD evidence for the “flip-flop”, i.e., the fluxtube recombination between the connected 4Q state and the “two-meson” state. On the confinement mechanism, the lattice QCD results indicate the flux-tube-type linear confinement in multi-quark hadrons. Finally, we propose a proper quark-model Hamiltonian based on the lattice QCD results.