Charged Higgs boson decay in supersymmetric TeV scale seesaw model Gi-Chol Cho (Ochanomizu Univ.) in collaboration with S. Kaneko (Valencia, Spain) and A. Omote (Ochanomizu) Joint Meeting of Pacific Region Particle Physics Communities conference Oct/30-Nov/03, 2006 Oct/31/2006 Gi-Chol Cho

1. Introduction origin of small neutrino mass? a smart explanation: seesaw mechanism (Yanagida, Gell-Man etal., ) too heavy “new particle” hopeless to test the seesaw mechanism directly Alternative? (testable model) possible to lower the seesaw scale? Oct/31/2006 Gi-Chol Cho

TeV scale see-saw mechanism associated with the supersymmetry breaking Arkani-Hamed, Hall, Murayama, Smith, Weiner, PRD64, 115011, 2001 Borzumati, Nomura, PRD64, 053005, 2001 March-Russell, West, PLB593, 181, 2004 framework: hidden sector SUSY breaking scenario (SUGRA) purpose: lower the right-handed neutrino mass (gauge invariant mass) to be O (1TeV) tool: Giudice-Masiero mechanism for the “ -problem” SUSY and gauge invariant mass term in the superpotential need to be the electroweak scale from the minimization condition of the Higgs potential Oct/31/2006 Gi-Chol Cho

-problem and Giudice-Masiero mechanism Hu + Hd … massless via a certain global symmetry G a chiral superfield X: singlet under GSM, but non-trivial under G v.e.v. of the F-comp. of X : “small” mu-term arises from the following operator after SUSY breaking gauge invariant mass (naturally ~Planck mass) could be lowered to the EW scale Oct/31/2006 Gi-Chol Cho

Plan of this talk study phenomenological consequences of the model in which the right- handed neutrino mass is lowered by the Giudice-Masiero mechanism Introduction Model corrections to the lightest Higgs boson mass sneutrino production via charged Higgs decay Summary Oct/31/2006 Gi-Chol Cho

Model Set-up (Arkani-Hamed etal, 2001) Arkani-Hamed, Hall, Murayama, Smith, Weiner, PRD64, 115011, 2001 Borzumati, Nomura, PRD64, 053005, 2001 March-Russell, West, PLB593, 181, 2004 Set-up (Arkani-Hamed etal, 2001) a field X: SM singlet, its v.e.v. breaks SUSY R-charge consider high. D operators in the leptonic sector Oct/31/2006 Gi-Chol Cho

Model right-handed neutrino mass: then, neutrino mass matrix is given as (v ~ mSUSY ) Oct/31/2006 Gi-Chol Cho

Model If a field X develops both A- and F-components v.e.v. Yukawa coupling ~ 10^-8 A-term ~10^3 GeV Oct/31/2006 Gi-Chol Cho

Model consequences of the model typical see-saw scale is O(TeV) neutrino Yukawa is naturally suppressed sneutrino A-term is not suppressed by the Yukawa coupling (in the MSSM, it will appear as a product w/ Yukawa) Oct/31/2006 Gi-Chol Cho

3. corrections to the lightest Higgs boson mass large SUSY breaking mass limit: a lightest Higgs mass is determined by the quartic coupling in the (SM) Higgs potential the scalar tri-linear coupling of 　　　　　　　　　 may affect the lightest Higgs mass through 1-loop correction Oct/31/2006 Gi-Chol Cho

negative contribution from the sneutrino loop diagram destructively interferes with the corrections in the MSSM (top quark, etc) Oct/31/2006 Gi-Chol Cho

Rh decreases for large Aν sneutrino loop negatively interferes w/ the top-stop contributions however, the correction is smaller than 2% for Oct/31/2006 Gi-Chol Cho

4. Sneutrino production in charged Higgs decay a typical process by a large (unsuppressed) A-term: MSSM: suppressed by lepton Yukawa couplings for first two generation Oct/31/2006 Gi-Chol Cho

decay modes of charged Higgs (top + bottom), (tau + neutrino)  overwhelmingly dominant in the MSSM selectron + sneutrino: enhanced due to the large A-term selectron may decay into electron + neutralino  signal? chargino + neutralino chargino may decay into electron + sneutrino could be background of the slepton+sneutrino mode detectability of the signal may depend on properties of chargino/neutralino Oct/31/2006 Gi-Chol Cho

example 1: higgsino like case lighter chargino/neutralino are almost higgsino mode is highly suppressed because of no Higgs-higgsino-higgsino vtx. Oct/31/2006 Gi-Chol Cho

example 2: mixed case the chargino+neutraino mode is larger than the sneutrino+slepton mode  a serious background Oct/31/2006 Gi-Chol Cho

discussion Oct/31/2006 Gi-Chol Cho

discussion @ILC w/ 100fb^-1 luminosity production cross section of ch.Higgs pair~10fb # of charged Higgs pair: 100-1000 /yr (ex) tanβ=3 and O(1) electrons: MSSM ~160 electrons (SUSY seesaw) such a signal can be expected only for tanβ>10 and　　　　　　　　 Oct/31/2006 Gi-Chol Cho

Summary phenomenology of the TeV scale SUSY see-saw model large (unsuppressed) scalar trilinear coupling sneutrino contribution to the lightest Higgs mass destructively interferes w/ the top-stop loop, but small sneutrino production from the charged Higgs decay is enhanced in some parameter space signal: excess of electrons from charged Higgs decay in some parameter space (tanβis small and a chargino is almost higgsino) Oct/31/2006 Gi-Chol Cho