International Journal of Modern Physics A

On the auspicious occasion of celebrating the 60th anniversary of the Yang–Mills theory, and Professor Yang’s many other important contributions to physics and mathematics, I will highlight the impressive milestones and landmarks that have been established in the last 60 years, as well as some interesting questions that still lie before us. The paper is written (without equations) for the interest of non-scientists as well as of scientists.

We give a brief overview of Professor Chen Ning Yang’s 13 important contributions to physics, especially his contributions to gauge theory. The great impact of his relevant papers is analyzed. Commentary is made on Yang’s distinctive style and trailblazing role in the history of physics.

The anomalous $WW\gamma$ coupling is probed through $e\gamma \to \nu W$ at the ILC. With a spectacular single lepton final state, this process is well suited to study the above coupling. Cross-section measurements can probe $\delta {\kappa }_{\gamma }$ to about $\pm 0.004$ for a luminosity of 100 fb${}^{-1}$ at 500 GeV center-of-mass energy with unpolarized electron beam. The limits derivable on ${\lambda }_{\gamma }$ from the total cross-section are comparatively more relaxed. Exploiting the energy-angle double distribution of the secondary muons, kinematic regions sensitive to these couplings are identified. The derivable limit on ${\lambda }_{\gamma }<0$ could be improved to a few per-mil, focusing on such regions. More importantly, the angular distributions at fixed energy values, and energy distribution at fixed angles present very interesting possibility of distinguishing the case of ${\lambda }_{\gamma }<0$ and ${\lambda }_{\gamma }\ge 0$.

Within the framework of Dyson–Schwinger equations (DSEs), we discuss the equation of state (EOS) and quark number densities of 2+1 flavors, that is to say, $u$, $d$, and $s$ quarks. The chemical equilibrium and electric charge neutrality conditions are used to constrain the chemical potential of different quarks. The EOS in the cases of 2 flavors and 2+1 flavors are discussed, and the quark number densities, the pressure, and energy density per baryon are also studied. The results show that there is a critical chemical potential for each flavor of quark, at which the quark number density turns to nonzero from 0; and furthermore, the system with 2+1 flavors of quarks is more stable than that with 2 flavors in the system. These discussions may provide some useful information to some research fields, such as the studies related to the QCD phase transitions or compact stars.

We calculate the contribution of the higher-twist Feynman diagrams to the large-$p_T$ inclusive gluon production cross-section in $\pi p$ collisions in case of the running coupling and frozen coupling approaches within perturbative and holographic QCD. The structure of infrared renormalon singularities of the higher-twist subprocess cross-section is obtained and the resummed higher-twist cross-sections (Borel sum) with the ones obtained in the framework of the frozen coupling approach and leading-twist cross-section are compared and analyzed.

In this paper, we consider a Lorentz-breaking scalar field theory within the Horava–Lifshtz approach. We investigate the changes that a space–time anisotropy produces in the Casimir effect. A massless real quantum scalar field is considered in two distinct situations: between two parallel plates and inside a rectangular two-dimensional box. In both cases, we have adopted specific boundary conditions on the field at the boundary. As we shall see, the energy and the Casimir force strongly depends on the parameter associated with the breaking of Lorentz symmetry and also on the boundary conditions.

Recently reported diboson excesses at LHC are interpreted as indications for heavy resonance with weak isospin 2 due to would-be anomalous interaction of the weak bosons, which is defined by a constant $\lambda$. In the framework of an approach to the spontaneous generation of such interaction, we obtain estimates for the effect, which qualitatively agrees with ATLAS data. Effects are predicted in inclusive production of $W^{+}{W}^{+}$, $W^{+}(Z,\gamma )$, $W^{+}{W}^{-}$, $(Z,\gamma )(Z,\gamma )$, $W^{-}(Z,\gamma )$, $W^{-}{W}^{-}$ resonances in the vicinity of $M_R\simeq 2\mathrm{\text{TeV}}$, which could be reliably checked at the upgraded LHC with $\sqrt{s}=13\mathrm{\text{TeV}}$.

In this paper, we analyzed the decay $B^0\to D_s^{{-}^{\ast }}{K}^{+}$ within QCD factorization (QCDF) and final state interaction (FSI) methods. At first, we consider the QCDF approach, where the final states are a pseudoscalar meson and vector meson. Then, we consider the FSI method where the intermediate states are $D^{-}{\rho }^{+}$ and ${\bar{D}}^0{\rho }^0$ via the exchange of $K^0$, $K^{0^{\ast }}$, $K^{+}$ and $K^{{+}^{\ast }}$ to improve the branching ratio. The above intermediate states are calculated by using the QCDF method. In the FSI effects, the results of our calculations depend on $\eta$ as the phenomenological parameter. The experimental branching ratio of this decay is $(2.19\pm 0.30)\times 10^{-5}$. Our results in QCDF approach is $(0.31\pm 0.06)\times 10^{-5}$, and with $\eta =3$, the improved branching ratio is $(2.02\pm 0.10)\times 10^{-5}$.