Dark Matter and a Suppression Mechanism for Neutrino Masses in the Higgs Triplet Model

1. Dark Matter and a Suppression Mechanism for Neutrino Masses in the Higgs Triplet Model Hiroaki SUGIYAMA (Univ. of Toyama, Japan) Contents • Introduction Higgs Triplet Model Motivations • Our Model - extended HTM - • LHC Phenomenology • Summary based on ‘S. Kanemura, HS, arXiv:1202.5231’

2. Introduction Neutrino masses are very different from other fermion masses. neutrino-specific mechanism to generate their masses ? Neutrino-specific mass term Majorana mass : (possible only for ) to be compensated by scalar fields Only the SM Higgs boson has vev. etc. ExtraHiggs bosons have vev. etc.

3. Higgs Triplet Model the SM + a complex Higgs triplet of W. Konetschny and W. Kumer, PLB70, 433 (1977) M. Magg and C. Wetterich, PLB94, 61 (1980) T.P. Cheng and L.F. Li, PRD22, 2860 (1980) J. Schechter and J.W.F. Valle, PRD22, 2227 (1980) Neutrino Mass Majorana mass matrix Soft breaking of Yukawa tem

4. Higgs potential : spontaneous breaking of no NG-boson for : explicit breaking of (“Majoron”) Yukawa interaction with a complex Higgs triplet Majorana mass matrix

5. Motivations Small option seems charming Light new particles (ex. ) production at LHC Sizable new coupling constants (ex. ) sizable LFV なるほど We want to suppress

6. ほう We want to supply the dark matter to the HTM

7. Our model Suppression of parameter Surprising model Resolve these issues at once (some relation between them) Supplying DM candidate “Idea is what resolves multiple issues at once” - Shigeru Miyamoto -

8. Dark Matter and a Suppression Mechanism for Neutrino Masses in the Higgs Triplet Model Hiroaki SUGIYAMA (Univ. of Toyama, Japan) Contents • Introduction Higgs Triplet Model Motivations • Our Model - extended HTM - • LHC Phenomenology • Summary based on ‘S. Kanemura, HS, arXiv:1202.5231’

9. Our Model S. Kanemura, HS, arXiv:1202.5231 HTM Only scalar sector is extended. SM broken by Suppression of parameter : allowed by conservation at the tree level : forbidden おっ : at the loop level

10. Our Model HTM Only scalar sector is extended. SM odd particles ほほぅ isDM candidate

11. 1-loop generation of parameter by utilizing DM candidate -odd particles (Dark mattercandidates) contribute to the loop なかまだー “オリゼー　ダイアグラム”

12. Estimation of Suppression of Case of (inert doublet DM) DM Example: satisfy LEP-II and WMAP おっ E. Lundstrom et al., PRD79, 035013 (2009) Case of (inert singlet DM) いいじゃん Example:

13. Dark Matter and a Suppression Mechanism for Neutrino Masses in the Higgs Triplet Model Hiroaki SUGIYAMA (Univ. of Toyama, Japan) Contents • Introduction Higgs Triplet Model Motivations • Our Model - extended HTM - • LHC Phenomenology • Summary based on ‘S. Kanemura, HS, arXiv:1202.5231’

14. Hopeful Probe of at the LHC : やるなー わー : The most interesting decay because of Good for BG reduction by imposing Negligible No No (See also, S. Kanemura and K. Yagyu, PRD85, 115009 )

15. Hopeful Probe of at the LHC : わー とりあえず かもすか with Negligible contribution from Negligible For example,

16. Hopeful Probe of at the LHC : わー c.f. usual HTM for the case of Additional leptons likely to exist. かもすぞー まかせろ

17. Summary The Higgs Triplet Model is extended. Dark mattercandidate (composed of and ) one-loop “one-loop” A strong suppression of parameter is possible. For example, suppressed (not small) would be probed at the LHC with

18. Backup

19. Higgs Triplet Model Yukawa interaction with a complex Higgs triplet Higgs potential

20. Scalar Potential

21. Masses of -Odd Scalars

22. Masses of -Even Scalars

23. Constraint on Inert Doublet Scalar DM E. Lundstrom et al., PRD79, 035013 (2009)