Browsing by Author "Chyi, TK"

Now showing 1 - 5 of 5

Gauge independent effective potential and the Higgs boson mass bound
(1999-07-01)
Lin, GL
;
Chyi, TK
;
物理研究所
;
Institute of Physics
We introduce the Vilkovisky-DeWitt formalism for deriving the lower bound of the Higgs boson mass. We illustrate the formalism with a simplified version of the standard electroweak model, where all charged boson fields as well as the bottom-quark field are disregarded. The effective potential obtained in this approach is gauge independent. We derive from the effective potential the mass bound of the Higgs boson. The result is compared to its counterpart obtained from the ordinary effective potential. [S0556-2821(99)06211-6].
Induced Einstein-Kalb-Ramond theory and the black hole
(1996-02-15)
Kao, WF
;
Dai, WB
;
Wang, SY
;
Chyi, TK
;
Lin, SY
A four-dimensional induced Einstein-Kalb-Ramond theory with a conformally coupled Kalb-Ramond term is discussed. It is argued that the Kalb-Ramond field is difficult to interpret as an axion field from a dynamical point of view, and hence tends to be unstable. One can, however, apply Routh's method to extract an effective action for the axion field. It is found that the Kalb-Ramond hair will turn the event horizon into a naked singularity. Such an exact solution is found and analyzed carefully.
Neutrino-photon scattering and its crossed processes in a background magnetic field
(1999-11-04)
Chyi, TK
;
Hwang, CW
;
Kao, WF
;
Lin, GL
;
Ng, KW
We study the neutrino-photon processes such as gamma gamma --> , v gamma --> v gamma, and --> gamma gamma in a background magnetic field smaller than the critical magnetic field Bc + m(e)(2)/e. Using Schwinger's formalism, we extract leading magnetic-field contributions to the above processes. Our result is valid throughout the kinematic regime where both neutrino and photon energies are significantly smaller than m(w). We briefly discuss the astrophysical implications of our result. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Weak-field expansion for processes in a homogeneous background magnetic field
(2000-11-15)
Chyi, TK
;
Hwang, CW
;
Kao, WF
;
Lin, GL
;
Ng, KW
The weak-field expansion of the charged fermion propagator under a uniform magnetic field is studied. Starting from Schwinger's proper-time representation, we express the charged fermion propagator as an infinite series corresponding to different Landau levels. This infinite series is then reorganized according to the powers of the external field strength B. For illustration, we apply this expansion to gamma --> nu<()over bar> and nu --> nu gamma decays, which involve charged fermions in the internal loop. The leading and subleading magnetic-field effects to the above processes are computed.
Weyl invariant black hole
(1996-02-15)
Kao, WF
;
Lin, SY
;
Chyi, TK
;
電子物理學系
;
物理研究所
The properties of the Weyl invariant black hole and its implications are studied. The calculation shows that there is no hair, up to a gauge choice, for a Weyl gauge field outside the event horizon of a black hole in the Weyl invariant limit. We also show that a scalar held will remain constant once the scale symmetry is broken spontaneously by the well-known Higgs potential. As a result, classical hair for the Weyl vector meson and scalar measuring field vanishes strictly in the presence of a spontaneously symmetry-breaking potential. Hence the no-hair theorem holds both in the Weyl invariant limit and the symmetry-breaking phase.