The vacuum energy of two CP (1) solitons on a torus is computed numerically. A numerical technique for the zeta-function regularisation is proposed to remove the divergence of the vacuum energy. After performing the numerical regularisation, we observe the effect of the vacuum energy on the two-soliton configuration.

The interaction of a cosmic string with a four-dimensional stationary black hole is considered. If a part of an infinitely long string passes close to a black hole it can be captured. The final stationary configurations of such captured strings are investigated. A uniqueness theorem is proved, namely it is shown that the minimal 2-D surface Σ describing a captured stationary string coincides wi...

We study gaugino condensation in presence of an anomalous U(1) gauge group and find that global supersymmetry is dynamically broken. An example of particular interest is provided by effective string models with 4dimensional Green-Schwarz anomaly cancellation mechanism. The structure of the hidden sector is constrained by the anomaly cancellation conditions and the scale of gaugino condensation ...

The thermodynamic potential is a quantity of central importance in statistical field theory, and a lot of interest has been devoted to its calculation. At high temperature, the perturbative expansion of the thermodynamic potential is known to 5th order in the coupling for the φ theory [1], [2], for QED [3], and for QCD [4], [5]. However, for physically relevant questions the applicability of th...

I will summarize theoretical issues in Working Group 1 at Nufact’01. In particular I will clarify a controversy on the optimum baseline L muon energy Eμ for measurements of the CP phase at a neutrino factory. If the uncertainty of the matter effect is assumed to be ±10%, which may be slightly too pessimistic, then the results from two groups agree (L ∼ 1000km, Eμ ∼ 10GeV).

We present an interacting action that lives in loop space, and we argue that this is a generalization of the theory for a free tensor multiplet. From this action we derive the Bogomolnyi equation corresponding to solitonic strings. Using the Hopf map, we find a correspondence between BPS strings and BPS monopoles in four-dimensional super Yang-Mills theory. This enable us to find explicit BPS s...

We study the radiative decay of Υ into a scalar glueball Υ → γGs using QCD factorization. We find that for this process the non-perturbative effects can be factorized into a matrix element well defined in non-relativistic QCD (NRQCD) and the gluon distribution amplitude. The same NRQCD matrix element appears also in leptonic decay of Υ and therefore can be determined from data. In the asymptoti...