1 / 20

Koji TSUMURA (NTU) B3SM 23-25/10/2011 on behalf of X.-G. He

An extended scalar sector to address the tension between a fourth generation and Higgs searches at the LHC. An extended scalar sector to address the tension between a fourth generation and Higgs searches at the LHC Xiao-Gang He, German Valencia, arXiv: 1108.0222.

avon
Download Presentation

Koji TSUMURA (NTU) B3SM 23-25/10/2011 on behalf of X.-G. He

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. An extended scalar sector to address the tension between a fourth generation and Higgs searches at the LHC An extended scalar sector to address the tension between a fourth generation and Higgs searches at the LHC Xiao-Gang He, German Valencia, arXiv: 1108.0222 Koji TSUMURA (NTU)B3SM 23-25/10/2011on behalf of X.-G. He

  2. Outline • Higgs boson in SM3 and in SM4 (Review) • ggh cross section, Higgs decay • LHC result • (Electroweak constraint) • SM4 to SM4S • An extended scalar sector • Tension between SM4 and extra scalar • Summary He, Valencia, arXiv:1108.0222

  3. Gluon fusion in SM3 • Gluon fusion mechanism • largest cross section!! Gluon Fusionggh even at 1-loop Sum over quark flavor

  4. Gluon fusion in SM3 • Gluon fusion mechanism top bottom Sum over quark flavor

  5. Gluon fusion in SM4 (sequential 4th generation) • Gluon fusion mechanism Enhance factor 9 top Sum over t and t’, b’

  6. Higgs decay in SM3 Main decay modes for heavy Higgs Z4l can determine mass of Higgs B(gg) is less than 10% Only 0.3%, but less BG events This can determine mass of light Higgs

  7. Higgs decay in SM4 Main decay modes for heavy Higgs Z4l can determine mass of Higgs Basically same as in SM3 t’,b’ B(gg) can be dominant in low mH region !! (40%)

  8. Higgs decay in SM4 Main decay modes for heavy Higgs Z4l can determine mass of Higgs Basically same as in SM3 Destructive cancellation Reduce to 0.03% from 0.3%. Enhance tot. width, cancellation in G(gg).

  9. Present status of Higgs boson search in SM3 • The results given @ LP2011 • Roughly speaking, mH=140-450GeV is excluded !! ~140GeV ~460GeV ~300GeV ~140GeV ~220GeV ~220GeV

  10. Present status of Higgs boson search in SM3  SM4 • The results given @ LP2011 (in separate modes) 600GeV 120GeV

  11. Gluon fusion revisited • Factor of 9? For low mass Higgs boson, top and t’, b’ give constant contributions. For high mass Higgs boson, top gives imaginary contribution and t’, b’ give real constant contributions.

  12. Present status of Higgs boson search in SM4 • The results given @ LP2011 • In SM4, mH=119-593GeV is excluded !!

  13. What do we learn from Review?  Tension @ one-loop level. SM4+X He, Valencia, arXiv:1108.0222

  14. SM4 to SM4S (Smart?, Survive?, Simple?,Scalar?) He, Valencia, arXiv:1108.0222 • New colored scalar • QCD production: Testable new scalar @ LHC • Color triplet scalar ( squarks); skip in this talk • Color octet scalar[SU(2) doublet] • Rich flavor pheno. due to Yukawa int. • New physics model  loop induced neutrino mass Gresham, Wise, PRD76,075003(2007) 4S 4 Manohar, Wise, PRD74,035009(2006) Color octet Perez, Wise, PRD80, 053006(2009) Color octet

  15. Exp. bound on octet • Flavor data • Kme, Bs Xs g, me g  [Minimal flavor violation] or [small Yukawa coupling] • Gluon fusion, and pair production Manohar, Wise, PRD74,035009(2006) Gresham, Wise, PRD76,075003(2007) S Gluon fusion (for Yt=1), No constraint for small Yukawa. S S* Pair production, complicated final states (not yet constrained)

  16. Scalar potential in SM4S • Scalar potential • Scalar Mass and Higgs coupling Manohar, Wise, PRD74,035009(2006) l2=2l3 (Custodial)

  17. Tension between SM4 and extra scalar • Effective Lagrangian He, Valencia, arXiv:1108.0222 Sum of SR, SI, S+ contributions. Over all sign can be flipped by l couplings Loop functions S

  18. Gluon fusion in SM4S He, Valencia, arXiv:1108.0222 • Tension between SM4 and extra scalar • Clearly, scalar contributions can be destructive!! • How big? • For l1=-8, mS~2v, the first term ~ -1 (comparable to one 4G quark) M ~ 1(top) +2(t’,b’) -1(colored scalar) +(…) • You may add more “exotic” colored scalars. Can be negative

  19. Summary • Higgs boson in SM3 and in SM4 (Review) • ggh cross section, Higgs decay • LHC result • (Electroweak constraint) • SM4 to SM4S • An extended scalar sector • Tension between SM4 and extra scalar He, Valencia, arXiv:1108.0222 Back to SM3 SM4 SM3 (SM4S2?)

  20. Backup Kribs, Plehn, Spannowsky, Tait, PRD76,075016(2007) • Electroweak constraint • Small splitting with mt’>mb’ 20

More Related