signature=02dffccf30e4e858322f183d95d6d4f3,DFF-385-03-02 hep-ph/0206192 The Scalar Sector of the Ran...

摘要：

We derive the effective potential for the Standard Model Higgs-boson sector interacting with Kaluza-Klein excitations of the graviton ($h_\\mu^{u n}$) and the radion ($\\phi$) and show that {\\it only} the Standard Model vacuum solution of $\\partial V(h)/\\partial h =0$ (h is the Higgs field) is allowed. We then consider the consequences of the curvature-scalar mixing xi R \\Hhat^\\dagger \\Hhat$ (where $\\Hhat$ is a Higgs doublet field on the visible brane), which causes the physical mass eigenstates h and $\\phi$ to be mixtures of the original Higgs and radion fields. First, we discuss the theoretical constraints on the allowed parameter space. Next, we give precise procedures for computing the h and $\\phi$ couplings given the {\\it physical} eigenstate masses, mh and $\\mphi$, xi and the new physics scales of the model. We show that LEP/LEP2 data implies that not both the h and $\\phi$ can be light. In the allowed region of parameter space, we examine numerically the couplings and branching ratios of the h and $\\phi$ for several cases with $\\mh=120\\gev$ and $\\mphi\\leq 300\\gev$. The resulting prospects for detection of the h and $\\phi$ at the LHC, a future LC and a $\\gam\\gam$ collider are reviewed. For moderate $|\\xi|$, both the anomalous $ho gg$ coupling and (when $\\mh>2\\mphi$) the non-standard decay channel $h o \\phi\\phi$ can substantially impact h discovery. Presence of the latter is a direct signature for non-zero xi. We find that $BR(h o \\phi\\phi)$ as large as $30 \\div 40 %$ is possible when $|\\xi|$ is large. Conversely, if $\\mphi>2\\mh$ then $BR(\\phio hh)$ is generally large. The feasibility of experimentally measuring the anomalous gg and $\\gam\\gam$ couplings of the h and $\\phi$ is examined.

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