Higgs Boson Mass In SUSY Seesaw Model

Jin Min Yang

Based on: Cao, Yang ， Phys. Rev. D 71, 11170 （ 2005 ）

[ hep-ph/0412315 ]

Institute of Theoretical Physics,

Academia Sinica, Beijing

Outline

• Physics

• Calculations

• Conclusion

Part I: Physics

(1) Higgs boson

SM: light Higgs EW data

MSSM: mh mZ (tree-level)

mh 130 GeV (loop-level)

(2) SUSY Seesaw Model

MSSM + R –superfields

(+ see-saw mechanism) SUSY See-saw Model

(3) Neutrino Yukawa coupling

large in SUSY see-saw model

Loop effects of neutrino in Higgs sector ?

Completely decouple at EW scale ??

(4) Recall top/stop loop effects

mh mZ mh 130 GeV

Top/stop loop effects

large Yukawa coupling

SUSY breaking

Top/stop effects in h-mass

(5) Back to neutrino/sneutrino effects

large Yukawa coupling ( )

Sizable effects

sizable SUSY breaking ( ? )

R mass scale MR >> weak scale

SUSY breaking for R soft-term MR

(6) Split SUSY

R soft-term MR (near GUT scale)

incur fine-tuning problem

split SUSY

(7) Our result

Neutrino/sneutrino contribution to mh:

opposite to top/stop effects

sizable (say -30 GeV) if

Comparison with top/stop effects:

Top/stop

Neutrino/sneutrino

Part II: Calculations

(1) With R –superfield, additional term in W:

3 3 matrix in flavor space

(2) Neutrino sector

Neutrino mass term:

2-component spinor 4-component spinor:

Neutrino Yukawa couplings:

(2) Sneutrino sector

Soft breaking terms:

Sneutrino mass term:

Sneutrino Yukawa couplings:

(3) Feynman diagrams

(4) Calcultion results

… …

Part III: Conclusion

SUSY see-saw model:

neutrino/sneutrino loop effects lighten mh if

SUSY Split-SUSY Split-SUSY see-saw

135 GeV

150 GeV

120 GeV (?)