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[en] The UPSILON-spectrum is studied for a potential model with relativistic corrections. This model includes spin-independent as well as spin-dependent terms. Leptonic decay rates and E1 decay matrix elements are given. For the fine structure of 2sup(3)Psub(J)states, r(2p)=*(M(2sup(3)Psub(2))-M(2sup(3)Psub(1))*)/*(M(2sup(3)Psub(1))-M(2sup(3)Psub(0))*)=0.61 is obtained, which can be compared with the experimental value of r(2p)sub(expr)=0.7. (Author)

[en] Electromagnetic transition amplitudes are calculated which are correct to the order of (v/c)sup(4) for arbitary parity-conserving interactions. They are presented in a compact form. And they can be applied to quarkonium spectroscopy either with derived interactions from QCD or with any phenomenological interactions. (Author)

[en] An effective hamiltonian is derived for quark-antiquark systems with emphasis on the annihilation kernels. It is good for perturbation theory to order v⁴/c⁴. We argue that spin-dependent constants due to the annihilation kernels play an important role in the hyperfine structure of heavy quark bound states. (author)

[en] It is shown that a systematic perturbation expansion of spontaneously broken gauge theory imposes a constraint on the upper as well as the lower limit of the Higgs boson mass. In the standard SU(2) X U(1) model, the Higgs boson mass is calculated to be between 13 GeV and 500 GeV for the weak mixing angle, theta approximately 35⁰. (Auth.)

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[en] It is proved that in any order of perturbation expansion the dimensionally regularized Feynman integration may be multiplied by an arbitrary analytic function of the space-time dimension, which can be absorbed in the redefinition of the bare coupling constants so that the finite renormalized quantities are unchanged. It is also shown that the Ward-Takahashi identities of a gauge theory are unaffected by this multiplication factor. A most convenient choice of the multiplicative analytic function is suggested and the effective potential of massless lambdaphi⁴ theory is calculated in the two-loop approximation as an explicit example