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CHARGED HIGGS BOSONS IN ’EXOTIC’ MODELS. Katri Huitu Department of Physical Sciences, HU and Helsinki Institute of Physics. Outline:. Introduction General 2HDMs R-parity violating models Fermiophobic Higgses Models with Higgs triplets:. Introduction
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CHARGED HIGGS BOSONS IN ’EXOTIC’ MODELS Katri HuituDepartment of Physical Sciences, HUandHelsinki Institute of Physics
Outline: Introduction General 2HDMs R-parity violating models Fermiophobic Higgses Models with Higgs triplets: Uppsala / Katri Huitu
Introduction The dynamics of the electroweak symmetry breaking is not understood in the Standard Model:Higgs boson mass is unstable in radiative corrections In extensions of the SM scalar sector:* better gauge coupling unification – with scale large enough to be consistent with proton decay;* neutrino mass (seesaw, R-parity breaking)* in cosmology electroweak phase transition may become possible;* one typically gets charged Higgs bosons Extensions with doublets: Two Higgs Doublet Model (2HDM), Minimal Supersymmetric Standard Model (MSSM), R-parity violating MSSM, Fermiophobic model … Extensions with triplets: Fermiophobic model, Left-right model, Georgi-Machachek model … Uppsala / Katri Huitu
Electroweak rparameter is experimentally close to 1 constraints on Higgs representations r=1 (2T+1)2-3Y2=1. Thus doublets can be added without problems with r. For the other representations, one has to finetune the VEVs to produce r=1. This may be motivated from other considerations. Uppsala / Katri Huitu
Other consequences of exotic representations: Coupling HiZZ receives contribution from any nonsinglet VEV (note that both Higgsstrahlung and gauge boson fusion need this coupling!).Parametrize: Sum rule for ci: Choudhury, Datta, KH, NPB 673 (2003) 385. Uppsala / Katri Huitu
With exotic additional representations of Higgs the doublet VEVs decrease Yukawa couplings increase. E.g. one Higgs doublet Measurement of Yukawa coupling constraint on E.g. top Yukawa coupling Uppsala / Katri Huitu
Triplet Higgses: real or complex- both representations needed if r=1: real increases r, while complex decreases. Choudhury, Datta, KH, NPB 673 (2003) 385. Uppsala / Katri Huitu
b sg Several contributions in MSSM: W – top loopH+ - top loopc- - up type quark loopgluino – down type squark loopc0 – down type squark loop Constructive interference Constructive or destructive interference with SM, depending on sign(m) T. Goto, Y. Okada,Prog.Theor.Phys.Suppl.123:213-220,1996. Uppsala / Katri Huitu
General 2HDM The Standard Model with two Higgs doubletsf1 and f2 r=1. The simplest extension of the SM with charged Higgs bosons. As in the MSSM five physical Higgs bosons: h, H, A, H The scalar potential Hermiticity: li are real Uppsala / Katri Huitu
Type I: one Higgs doublet provides masses to all quarks (up- and down-type quarks) (~SM). Type II: one Higgs doublet provides masses for up-type quarks and the other for down-type quarks (~MSSM). Type III,IV: different doublets provide masses for down type quarks and charged leptons. • V. Barger, J.L. Hewett, R.J.N. Phillips, Phys. Rev. D 41, 3421–3441 (1990). Uppsala / Katri Huitu
V. Barger, J.L. Hewett, R.J.N. Phillips, Phys. Rev. D 41, 3421–3441 (1990). The branching ratios can be very different from the SM. tan b is important for phenomenology! For processes which depend only on quark sector, models I and IV are similar, as well as models II and III. Uppsala / Katri Huitu
Couplings H-H-V: Charged Higgs decay modes if mH+<mW+mh: Uppsala / Katri Huitu
Branching ratios of charged Higgses in 2HDM model II (MSSM): M. Carena, H. Haber, Prog.Part.Nucl.Phys.50:63-152,2003. Note that there is no H+W-Z coupling in 2HDM at tree-level No gauge boson fusion in production at hadron colliders Uppsala / Katri Huitu
Singly charged Higgs mass limit from LEP: Assumed decay channels LEP Higgs working group,LHWG note 2001-05. Uppsala / Katri Huitu
V. Barger, J.L. Hewett, R.J.N. Phillips, Phys. Rev. D 41, 3421–3441 (1990). Limits from bsg in 2HDM B(bsg) 1 In model II the contribution is always bigger than in the SM, while in model I one can have strong cancellations due to –cot b in the coupling. 10-2 10-4 10-6 1 10-1 mH+[GeV] 10-2 50 100 250 10-3 500 THDM II: mH+>(244+63/tan b) GeV 10-4 Grinstein, Springer, Wise, NPB 339 (1990) 269. Uppsala / Katri Huitu
R-parity violating MSSM: 2HDM II with supersymmetric partners included, and no R-parity. MSSM superpotential: If R-parity (Rp=(-1)3(B-L)+2s) is not assumed, one should add: Unless the couplings are very small, proton decays fast if both lepton and baryon number violating couplings are allowed forbid B violating couplings. The bilinear term mixes lepton and Higgs sectors. charged Higgses mix with charged sleptons Uppsala / Katri Huitu
A.G. Akeroyd, M.A. Diaz, J. Ferrandis, M.A. Garcia-Jareno, J.W.F. Valle, Nucl.Phys.B529:3-22,1998 Already at tree-level, mH+ can be lighter than in the MSSM with R-parity; In the MSSM mH+ > mW Uppsala / Katri Huitu
Limits from bsg in R-parity violating MSSM Model dependent:- Charged Higgs and chargino loops interact destructively- very heavy squarks chargino loops can be neglected In the case of R-parity violation:Mixing of charged bosons with staus decrease the bounds MSSM R-parity violating MSSM Diaz, Torrente-Lujan, Valle, NPB 551 (1999) 78. Uppsala / Katri Huitu
For light charged Higgses (=charged scalar with strongest coupling to squarks) and charginos R-parity violating MSSM, mH+ > 75 GeV MSSM, mH+ > 110 GeV Diaz, Torrente-Lujan, Valle, NPB 551 (1999) 78. Uppsala / Katri Huitu
Important consequences of R-parity violation: The LSP is no longer stable, but decays to the Standard Model particles little or no missing energy in the processes. lots of jets and leptons. sparticles can be produced singly. Phenomenology depends on the LSP: stau LSP tn (l-type coupling) tb (l’-type coupling) through the Higgs component, if only bilinear couplings mimics H+ If not LSP, stau decays through stautc0 Uppsala / Katri Huitu
E.g. bilinear R-parity violating branching ratios:H+ may decay through mixing with stau Akeroyd et al, NPB 529 (1998) 3. Uppsala / Katri Huitu
Fermiophobic Higgs bosons Coupling to fermions very suppressed or zero, e.g. 2HDM type I or a triplet model (to be discussed). Clear signal for Higgs decay h gg or h VV (V=W,Z) = cos a / sin b 0 (even if exactly zero, a coupling can arise in radiative corrections) h f Production at LHC: pp H+/-h, with the decay H+/- hW*, h gg Uppsala / Katri Huitu
A.G. Akeroyd, M.A. Diaz, J. Pacheco, Phys.Rev.D70:075002,2004. Double h production, h gg Mcharged Higgs=150 GeV Uppsala / Katri Huitu
Models with triplet Higgses The simplest model contains one complex triplet The minimal Higgs content is Seesaw mechanism provides masses for neutrinos: Uppsala / Katri Huitu
Singly charged Higgs is a mixture of doublet and triplet charged Higgs decay modes Modes common with 2HDMs: KH,Laitinen,Maalampi, NPB 598 (2001) 13. ytt=1 ytt=0.1 Branching ratios different due to the Dll –coupling and tree-level H+W-Z-coupling. ytt=0 Uppsala / Katri Huitu
A vertex possible at tree-level only in models with larger than doublet presentations. In a model with triplets, proportional to the triplet VEV. The coupling comes from the kinetic term: The vertex is given by Uppsala / Katri Huitu
A charged Higgs boson can be produced from gauge boson fusion, High pT jets to the forward and backward directions from the scalar boson; No color flow in the central region; Use kinematic cuts to separate signal LHC E. Asakawa, S. Kanemura, Phys.Lett.B626:111-119,2005. Uppsala / Katri Huitu
Doubly charged Higgs in triplet models: Doubly charged Higgs does not mix with anything and it does not couple to quarks. Doubly charged Higgs is a clear evidence of triplet representations. Uppsala / Katri Huitu
M. Kuze, Y.Sirois, Prog.Part.Nucl.Phys.50:1-62,2003 Doubly charged Higgs mass limit Uppsala / Katri Huitu
A special case of triplet models is a supersymmetric left-right model, based on Because of the gauged B-L, the R-parity is exactly conserved, but breaks spontaneously. The model contains minimally two right-handed triplet Higgses and two bidoublet Higgses. Typically one doubly charged Higgs is light and decays to leptons. Uppsala / Katri Huitu
D++WR+WR+,D+WR+,D+D+ D++l+l+ # of events 1 3 5 10 Discovery limits for D++R at LHC. Maalampi, Romanenko, Phys.Lett.B532:202-208,2002 Uppsala / Katri Huitu
Summary Differences to MSSM: Coupling(triplet model) Mass can be lower than in the MSSM New particles: H++ (triplet model with seesaw) Branching ratios different: H+nt (2HDM, triplet) H+tc (R-parity violation) H+W*h, hgg (fermiophobic) H+W+Z (triplet) Uppsala / Katri Huitu