Modern Physics Letters A

We review a number of results for the spectrum and inclusive decays of heavy quarkonium systems which can be derived from QCD under well controlled approximations. They essentially follow from the hierarchy of scales in these systems, which can be efficiently exploited using non-relativistic effective field theories. In particular, we discuss under which conditions non-relativistic potential models emerge as effective theories of QCD.

It is argued that the internal dynamics of a baryon, as a bound state of QCD-strings and quarks, may be captured by a theory of matrix coordinates.

We compute the boundary stress-energies of time-dependent asymptotically AdS spacetimes in five and seven dimensions, and find that their traces are equal to the respective four- and six-dimensional field-theoretic trace anomalies. This provides good supporting evidence in favor of the AdS/CFT correspondence in time-dependent backgrounds.

In this study, neutron-emission spectra produced by (n,xn) reactions on nuclei ²³²Th have been calculated. Angle-integrated cross-sections in neutron induced reactions on targets ²³²Th have been calculated at the bombarding energies from 2 MeV to 18 MeV. We have investigated multiple pre-equilibrium matrix element constant from internal transition for ²³²Th(n,xn) neutron emission spectra. In the calculations, the geometry dependent hybrid model and the cascade exciton model including the effects of pre-equilibrium have been used. Pre-equilibrium direct effects have been examined by using full exciton model. In addition, we have described how multiple pre-equilibrium emissions can be included in the Feshbach–Kerman–Koonin (FKK) fully quantum-mechanical theory. By analyzing (n,xn) reaction on ²³²Th, with the incident energy from 2 MeV to 18 MeV, the importance of multiple pre-equilibrium emission can be seen clearly. All calculated results have been compared with experimental data. The obtained results have been discussed and compared with the available experimental data and found agreement with each other.

We investigate the SU(3)³ GUT model when signs of the model (precursors), due to low compactification scale, appear before the gauge couplings of the Standard Model get unified. The Kaluza–Klein state contribution seems to lead the gauge couplings to unification through a wide energy scale only in the case when the colour group is augmented to SU(4).

We analyze the D→ππ decay channels at the leading order, α_s corrections with the QCD factorization and the soft-gluon corrections with the light cone QCD sum rule. Comparing with the experimental result, the calculations of the D⁰→π⁺π^- and D⁺→π⁺π⁰ decay are much better under the consideration of the contributions of factorization parts, α_s corrections and soft-gluon effects. However, the calculation result is one order less than the experimental result in D⁰→π⁰π⁰ decay. It may have large effects of final state interaction in the decay channel.