SU(4) symmetry and hadron classification

We present here a quark model in SU(4) and classify hadrons. Weight diagrams are drawn. We give some mathematical aspects of SU(4) symmetry in the light of charmed quantum number.We are thankful to Prof. N. N.Raina for keen interest shown in our work and constant encouragement.     

SU (4) × SU (4) symmetry breaking and its implications for SU (3) × SU (3) breaking

We investigate models where the SU (4) × SU (4) symmetry breaking Hamiltonian, $\text{H}$_SB, belongs to the (15, 15) and $\text{(10,}\text{10}\text{) + (}\text{10}\text{, 10)}$ representations, and show how they are equivalent to models of SU (3) × SU (3) breaking where $\text{H}$_SB belongs to a mixture of different representations. The results for the ππ scattering lengths in the (15, 15) model are outside the experimental limits, but the $\text{(10,}\text{10}\text{) + (}\text{10}\text{, 10)}$ model yields solutions with a wide range of values for the scattering lengths within the experimental bounds.     

The hidden SO(4) symmetry of general SU(2) thirring models

General four-fermion interactions in two dimensions with SU(2) invariance are shown to possess a hidden SO(4) symmetry. As a consequence physical states belong to irreducible representations of the two commuting O(3) subgroups and their interactions decouple accordingly. Two independnet stable trajectories of the renormalization group are shown to exist perturbatively and are consistently reproduced by abelian bosonization.     

Dynamical rearrangement of SU(3) symmetry

The dynamical rearrangement of the SU(3) group is studied in connection with a 2-dimensional analogy of Holstein-Primakoff transformation. Infrared effect and low energy theorems are considered.     

SU(4) flavor symmetry breaking in D-meson couplings to light hadrons

The European Physical Journal A - This work presents a simple method to determine the significant partial wave contributions to experimentally determined observables in pseudoscalar meson...     

Is the SU(3) pattern evidence for SU(3) symmetry?

The results obtained in this paper show that the SU(3) pattern in the spectra and transition rates of even-even nuclei appear qualitatively as a general feature of a large class of quadrupole-phonon models, independently of SU(3) symmetry. This pattern reflects the truncation of the quadrupole phonon space, incorporated via truncation operator in the fourth-order anharmonic quadrupole-phonon Hamiltonian. Three particular forms of the truncation operator are considered, corresponding to three models, namely the truncated quadrupole-phonon model (TQM), equivalent to the well-known interacting-boson model (IBM), the step-truncated quadrupole-phonon model (STQM), equivalent to a standard anharmonic quadrupole-phonon model and the linearly truncated quadrupole-phonon model (LTQM), introduced here. The results obtained provide a basis for a broader scope for the considerations in the SU(3) limit.     

Chiral SU4 × SU4 symmetry breaking and the Cabibbo angle

The structure of chiral SU₄ × SU₄ symmetry breaking, in the limit of exact chiral SU₂ × SU₂ symmetry, is related to the Cabibbo angle, thus leading to a satisfactory determination of the Cabibbo angle in terms of the kaon and D-meson masses and decay constants.     

SU(3) × SU(3) symmetry breaking in a simple model

A field-theoretical model, due to Lévy, is studied. It contains a triplet of quarks and a pseudoscalar and a scalar meson nonet. The original SU(3) × SU(3) symmetry is broken by terms linear in the scalar meson fields. A renormalization and regularization procedure is defined in order to remove the ultra-violet divergences. The possibility of a spontaneous breakdown of the symmetry is described and the Goldstone theorem is verified in the one-loop approximation.     

SU(N) gauge fields with spherical symmetry

A method to construct spherically symmetricSU(N) gauge fields and an invariant classification are presented. For the groupSU(3) the ansätze are completely elaborated. The corresponding sourcelessSU(3)-Yang-Mills equations are discussed.     

Exact SU(n) instantons with cylindrical symmetry

We construct SO(3) symmetric, irreducible instantons in an SU(n) gauge theory. The solutions are symmetric with respect to J = ?ir × ? + T, where T spans the maximal SO(3) subalgebra of SU(n). Our ansatz as well as the resulting self dual equations are closely related to those for monopoles.     

An SU(3) symmetry for light neutrinos

It is proposed that light neutrinos form a triplet in a global SU(3) symmetry in the mass eigenstate basis. Assuming that the SU(3) symmetry is broken in the direction , and after going to the flavor basis, we predict the atmospheric mixing angles sin²θ₂₃=0.5 and sinθ₁₃=0, if ν_μ–ν_τ symmetry is assumed. In the flavor basis, the diagonal part of the matrix coefficient of b (the dominant part) is found to transform like . Imposing the same condition on the matrix coefficient of a fixes the solar mixing angle, . The implications for neutrinoless double beta decay are discussed.     

Simultaneous dimerization and SU(4) symmetry breaking of 4-color fermions on the square lattice

Using infinite projected entangled-pair states, exact diagonalization, and flavor-wave theory, we show that the SU(4) Heisenberg model undergoes a spontaneous dimerization on the square lattice, in contrast with its SU(2) and SU(3) counterparts, which develop Néel and three-sublattice stripelike long-range order. Since the ground state of a dimer is not a singlet for SU(4) but a 6-dimensional irreducible representation, this leaves the door open for further symmetry breaking. We provide evidence that, unlike in SU(4) ladders, where dimers pair up to form singlet plaquettes, here the SU(4) symmetry is additionally broken, leading to a gapless spectrum in spite of the broken translational symmetry.     

SU(5) symmetry of spdfg interacting boson model

The extended interacting boson model with s-, p-, d-, f- and g-bosons included (spdfg IBM)is investigated. The algebraic structure including the generators, the Casimir operators of the groups at the SU(5) dynamical symmetry and the branching rules of the irreducible representation reductions along the group chain are obtained. The typical energy spectrum of the symmetry is given.