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Scenarios of Higgs bosons and Z’ manifestations in the minimal gauge extension of the SM

Scenarios of Higgs bosons and Z’ manifestations in the minimal gauge extension of the SM. A.Beylin, V.Beylin , A.Pivovarov SFU, MIPT. QFTHEP-2011 24.09.2011 – 01.10.2011. Outline. An introduction Higss sector of the model Z’-boson H – Z’ combined effect in ttZ Conclusions.

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Scenarios of Higgs bosons and Z’ manifestations in the minimal gauge extension of the SM

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  1. Scenarios of Higgs bosons and Z’ manifestations in the minimal gauge extension of the SM A.Beylin, V.Beylin, A.Pivovarov SFU, MIPT QFTHEP-2011 24.09.2011 – 01.10.2011

  2. Outline • An introduction • Higss sector of the model • Z’-boson • H – Z’ combined effect in ttZ • Conclusions

  3. Beyond the SM: MSSM (two neutral Higgs bosons +…),B-L(two neutral Higgs bosons),LH (Higgs boson + extra vectorlike quark)… • Specific manifestations in the structure of invariant distributions; • Interference with the QCD leads to the “peak-and-dip” picture; • A possibility to “switch off” some channels (weak coupling heavy Higgs with tt-pair in the MSSM for some tgβ, for example) • Most simple model to study interference effects – the U(1)B-L gauge extension of the SM – a small number of parameters.

  4. The U(1) SM extensions Early papers: R.N.Mohapatra, R.E.Marshak (1980); A.Masiero, J.Nieves, T.Yanagida(1982); R.N.Mohapatra, G.Senjanovic (1983) and others… More recent papers: S.Khalil (2006); W.Emam, S.Khalil (2007); W.Emam, P.Mine (2009); L.Basso, S.Moretti, G.M.Pruna, A.Belyaev, C.H.Shepherd-Themistocleus (2008 – 2011). Interference effects: K.Gaemers, F.Hoogeven (1984); D.Dicus, A.Stange, S.Willenbrock (1994); D.Berdine, N.Kauer, D.Rainwater (2007); R.Barcelo, M.Masip (2010). And many others.

  5. The minimal gauge extension of the SMSU(3)Cx SU(2)Wx U(1)EMx U(1)B-LKnown problems of the SM The extended model contains: • extra gauge vector Z’ – boson from the B-L gauge symmetry • extra (heavy) singlet Higgs boson • three right-handed (heavy) neutrino the mixing and masses of neutrino, the problem of mass hierarchy, the Higgs boson(s) origin, the DM nature, baryon asymmetry.

  6. There are two Higgs bosons, h1,h2 with masses Hereλ1, λ2 , λ3 , x, v- Yukawa constants and vacuum shifts for the Higgs fields

  7. “Strong coupling” regime ≈ ≈ 3· ≈ α- scalar’s mixing angle α≈π/4

  8. Z’- extra gauge boson hiZZ’ interaction: • ZZ’ mixing angle, it is ~ 1/1000 RG analysis and restrictions from LEP and LHC prefer MZ’ ~ O(TeV), MZ’ /g’≥7 TeV hiZ’Z’ interaction: The model contains heavy right neutrino with an interesting phenomenology See: W.Emam, S.Khalil, 2007; L.Basso e.a., 2009

  9. pp h1 h2 ttZvia two Higgs bosons states, Z’ttZ’* and ttZ* final states can be interesting

  10. tt-pair squared mass distribution for different Mh andα “light” Z’case Mh1=140 GeV, Mh2 =600 GeV, MZ’ =700 GeV, g’= 0.1 α = π/6 Mh1=140 GeV, Mh2 =600 GeV, MZ’ =700 GeV, g’= 0.1 α = π/3 Mh1=480 GeV, Mh2 =820 GeV, MZ’ =700 GeV, g’= 0.1 α = π/3

  11. tt-pair squared mass distribution for different Mh andα“heavy” Z’case Mh1=480 GeV, Mh2 =820 GeV, MZ’ =3.5 TeV, g’= 0.5 α = π/4 Mh1=480 GeV, Mh2 =820 GeV, MZ’ =3.5 TeV, g’= 0.5 α = π/6 Mh1=140 GeV, Mh2 =600 GeV, MZ’ =3.5 TeV, g’= 0.5 α = π/4

  12. The ratios of differential distributions in Eb for the extended model with U(1)B-L and the MSSM in the H tbW decay Mh =270 GeV, α = π/3 tg β =1.5 Mh =270 GeV, α = π/6 Mh =460 GeV, α = π/4

  13. tg β =30 Mh =270 GeV, α = π/4

  14. Conclusions • Interference effects in the models with two scalar states are important, especially if their masses are close (“strong coupling” regime in U(1)B-L ), their contributions for the process are significant depending on the parameters. • Z’ peak is seen in the distributions, however its width and amplitude strongly depend on the model parameters (scalar masses, mixing angle, extra U(1) coupling g’, widths of scalars) • Distributions for the Higgs boson decays in the models with two neutral scalars are similar and nearly coincides in H tbW (U(1)B-L and MSSM) for some values of the mixing angle and small tgβ. For high tgβ predictions differs substantially. • Known “peak-and-dip” structure induced by interference is substantially eroded in the case with two scalars.

  15. tt-pair squared mass distribution for different Mh andα“heavy” Z’case (smoothed) Mh1=480 GeV, Mh2 =820 GeV, MZ’ =3.5 TeV, g’= 0.5 α = π/6 Mh1=140 GeV, Mh2 =600 GeV, MZ’ =3.5 TeV, g’= 0.5 α = π/4 Mh1=480 GeV, Mh2 =820 GeV, MZ’ =3.5 TeV, g’= 0.5 α = π/4

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