184 research outputs found

### Top quark, heavy fermions and the composite Higgs boson

We study the properties of heavy fermions in the vector-like representation
of the electro-weak gauge group $SU(2)_W\times U(1)_Y$ with Yukawa couplings to
the standard model Higgs boson. Applying the renormalization group analysis, we
discuss the effects of heavy fermions to the vacuum stability bound and the
triviality bound on the mass of the Higgs boson. We also discuss the
interesting possibility that the Higgs particle is composed of the top quark
and heavy fermions. The bound on the composite Higgs mass is estimated using
the method of Bardeen, Hill and Lindner, 150GeV$\leq m_H\leq$ 450GeV.Comment: 10 pages and 6 figures. This paper replaces and is an extended
version of hep-ph/9602340 (published in Phys. Lett. B370(1996)201;Erratum
B382(1996)448

### Some Remarks on Exotic Resonances

Using large $N_c$ counting rule, it is argued that tetra-quark resonances do
not exist. Also it is pointed out that there exists the violation of exchange
degeneracy in the exotic $KN$ scattering channel. It implies either the failure
of resonance saturation assumption or it suggests the existence of exotic
baryon resonances in such a channel.Comment: Talk given at 10th International Symposium on Meson-Nucleon Physics
and the Structure of the Nucleon (MENU 2004), Beijing, China, 29 Aug - 4 Sep
200

### A Numerical Analysis to the {$\pi$} and {K} Coupled--Channel Scalar Form-factor

A numerical analysis to the scalar form-factor in the $\pi\pi$ and KK
coupled--channel system is made by solving the coupled-channel dispersive
integral equations, using the iteration method. The solutions are found not
unique. Physical application to the $\pi\pi$ central production in the $pp\to
pp\pi\pi$ process is discussed based upon the numerical solutions we found.Comment: 8 pages, Latex, 3 figures. Minor changes and one reference adde

### Some Remarks on the Final State Interactions in $B\to \pi K$ Decays

Careful discussions are made on some points which are met in studying B decay
final state interactions, taking the $B^0\to \pi^+ K^-$ process as an example.
We point out that $\pi$--exchange rescatterings are not important, whereas for
$D^*$ and $D^{**}$ exchanges, since the $B^0\to D^+D_s^-$ decay has a large
branching ratio their contributions may be large enough to enhance the $B\to
\pi K$ branching ratio significantly.
However our estimates fail to predict a large enhancement.Comment: 5 pages, use elsart.sty; The previous version is erroneous in
explaining the "charm peguin" effects. No large enhancement to $B\to \pi K$
is found through $D^+D_s^-$ intermediate stat

### FINAL STATE INTERACTIONS OF $B\to DK$ DECAYS

We study the final state strong interactions of the $B\rightarrow DK$ decay
processes, using the Regge model. We conclude that the final state interaction
phases are very small, typically a few degrees. Neglecting final state
interactions in obtaining the weak decay amplitudes is a good approximation.Comment: 10 pages, standard latex without figure

### A Renormalization Group Analysis of the Higgs Boson with Heavy Fermions and Compositeness

We study the properties of heavy fermions in the vector-like representation
of the electro-weak gauge group $SU(2)_W\times U(1)_Y$ with Yukawa couplings to
the standard model (SM) Higgs boson. Using the renormalization group analysis,
we discuss their effects on the vacuum stability and the triviality bound on
the Higgs self-coupling, within the context of the standard model (i.e., the
Higgs particle is elementary). Contrary to the low energy case where the
decoupling theorem dictates their behavior, the inclusion of heavy fermions
drastically change the SM structure at high scale. We also discuss the
interesting possibility of compositeness, i.e., the Higgs particle is composed
of the heavy fermions using the method of Bardeen, Hill and
Lindner~\cite{BHL91}. Finally we briefly comment on their possible role in
explaining $R_b$ and $R_c$.Comment: Some typographic errors are corrected and title is changed. Version
to appear in Physics Letter B. 9 pages 6 Postscript figures, use epsf.st

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