Higgs-Boson Interactions within the Randall-Sundrum Model.pdfVIP

a r X i v : h e p - p h / 0 2 0 6 1 9 7 v 1 2 0 J u n 2 0 0 2 UCD-02-09 DFF-389-06-02 June, 2002 HIGGS-BOSON INTERACTIONS WITHIN THE RANDALL-SUNDRUM MODELa) Daniele DOMINICI 1), b) Bohdan GRZADKOWSKI 2), c) John F. GUNION 3), d) Manuel TOHARIA 3), e) 1 Dipartimento di Fisica, Florence University and INFN, Via Sansone 1, 50019 Sesto. F. (FI), ITALY 2 Institute of Theoretical Physics, Warsaw University, Hoz?a 69, PL-00-681 Warsaw, POLAND 3 Davis Institute for High Energy Physics, University of California Davis, Davis, CA 95616-8677, USA Dedicated to Stefan Pokorski on his 60th birthday. To appear in Acta Physica Polonica B ABSTRACT The scalar sector of the Randall-Sundrum model is discussed. The effective poten- tial for the Standard Model Higgs-boson (h) interacting with Kaluza-Klein excita- tions of the graviton (hν nμ ) and the radion (φ) has been derived and it has been shown that only the Standard Model vacuum solution of ?V/?h = 0 is allowed. The theoretical and experimental consequences of the curvature-scalar mixing ξ R H??H? introduced on the visible brane are considered and simple sum rules that relate the couplings of the mass eigenstates h and φ to pairs of vector bosons and fermions are derived. The sum rule for the ZZh and ZZφ couplings in combination with LEP/LEP2 data implies that not both the h and φ can be light. We present ex- plicit results for the still allowed region in the (mh, mφ) plane that remains after imposing the LEP upper limits for non-standard scalar couplings to a ZZ pair. The phenomenological consequences of the mixing are investigated and, in particu- lar, it is shown that the Higgs-boson decay h → φφ would provide an experimental signature for non-zero ξ and can have a very substantial impact on the Higgs-boson searches, having BR(h → φφ) as large as 30÷ 40%. PACS: 04.50.+h, 12.60.Fr Keywords: extra dimensions, Higgs-boson sector, Randall-Sundrum model a) Talk presented by J. F. Gunion at the “Planck 02”, Fifth European Meeting