Low-energy QCD in its sector with Nf = 3 flavours of almost massless up and down quarks (mu ≈ md ∼ O(5MeV)) and a slightly heavier strange quark (ms ∼ O(100MeV)) is known to have the following characteristic symmetry breaking pattern: the Goldstone bosons related to spontaneously broken chiral SU(3) × SU(3) symmetry are identified with the pions and kaons. Their masses originate from explicit s...

Parity-time (PT) symmetry is of great interest. The reciprocal and unidirectional features are intriguing besides the (PT) symmetry phase transition. Recently, the reciprocal transmission, unidirectional reflectionless and invisibility are intensively studied. Here, we show the reciprocal reflection/transmission in (PT)-symmetric system is closely related to the type of (PT) symmetry, that is, ...

Using the standard auxiliary field method, we derive from the extended NambuJona-Lasinio model an effective meson action containing vector and axial-vector mesons in addition to Goldstone bosons. The vector and axial-vector mesons in this effective action transform as gauge fields of hidden local symmetry Glocal = [U(n)L × U(n)R]local. Here, the realization of enlarged hidden local symmetry is ...

We construct a new class of asymptotically flat black hole solutions in EinsteinYang-Mills and Einstein-Yang-Mills-dilaton theory. These black hole solutions are static, and they have a regular event horizon. However, they possess only axial symmetry. Like their regular counterparts, the black hole solutions are characterized by two integers, the winding number n and the node number k of the ga...

We study N = 2 supersymmetric SU(2)/U(1) and SL(2, R)/U(1) gauged WessZumino-Witten models. It is shown that the vector gauged model is transformed to the axial gauged model by a mirror transformation. Therefore the vector gauged model and the axial gauged model are equivalent as N = (2, 2) superconformal field theories. In the SL(2, R)/U(1) model, it is known that axial-vector duality relates ...