Radiative B-L symmetry breaking and the Z' mediated SUSY breaking

1. Radiative B-L symmetry breaking and the Z' mediated SUSY breaking Takayuki Kubo (KEK) arXiv:0804.3933 [hep-ph] work in collaboration with Tatsuru Kikuchi (KEK) SUSY 08, Korea

2. Outline • Introduction • Review of the U(1)B-L extended MSSM • Review of the Z’-mediated SUSY breaking • Results • Summary SUSY 08, Korea

3. Introduction (1) • The U(1)B-L extended MSSM has fascinating features. • Right-handed neutrinos are naturally introduced in order to cancel the anomalies. • B and L violating interactions are forbidden. Discrete symmetries (e.g. R-parity) are not needed ! • Seesaw scale can be understood as a breaking scale of the U(1)B-L symmetry. SUSY 08, Korea

4. Introduction (2) • Z’-mediated SUSY breaking need only an extra U(1)’ gauge multiplet. • P. Langacker et.al., Phys. Rev. Lett. 100 (2008) 041802 • We can identify U(1)B-L as U(1)’ • We treat the U(1)B-L extended MSSM in a framework of the Z’-mediated SUSY breaking. • Radiative B-L symmetry breaking is achieved. • Obtained mass spectra are much different from mSUGRA. SUSY 08, Korea

5. Review of the U(1)B-L extended MSSM (1) • SM and MSSM have a global U(1)B-L symmetry. But it can not be a local one, since Tr(B-L)3≠0. Q : -1/3, Uc : 1/3, Dc : 1/3, L : -1, Ec : +1, H1 : 0, H2 : 0 • Now, add the right-handed neutrinos Nc : +1 . Tr(B-L)3=0 and U(1)B-L can be a local symmetry ! • Right-handed neutrinos are naturally introduced. SUSY 08, Korea

6. Review of the U(1)B-L extended MSSM (2) • U(1)B-L symmetry forbids B and L violating terms! UcDcDc : -1/3-1/3-1/3≠0, LQDc : -1+1/3-1/3≠0, LLEc : -1-1+1≠0, etc. • U(1)B-L symmetry forbids B and L violating terms! Discrete symmetries (e.g. R-parity) are not needed ! SUSY 08, Korea

7. Review of the U(1)B-L extended MSSM (3) • Superpotential • ∆1 and ∆2 are MSSM siglets with B-L charges ∆1 : -2 and ∆2 : +2. (∆2 is necessary to cancel the anomaly produced by the fermionic component of ∆1.) • U(1)B-L symmetry forbids MNNcNcterm ! • Instead, ‹∆1› gives the seesaw scale. • Seesaw scale can be understood as the breaking scale of the U(1)B-L symmetry. new comers SUSY 08, Korea

8. Review of the Z’-mediated SUSY breaking (1) • Extra gauge multiplet U(1)’ couples to both visible and hidden sectors. • U(1)’ gaugino acquires its mass at a scale Λsby a dynamics in the hidden sector. • All the soft-terms are induced by the U(1)’ gaugino mass through the RGE. Dynamical SUSY Breaking Visible SUSY 08, Korea

9. Review of the Z’-mediated SUSY breaking (2) • At the scale Λs, only the U(1)’ gaugino acquires its mass. • MSSM gauginos and scalars acquire their masses through the RGE. • Taking Ma≈100GeV, we have the U(1)’ gaugino mass≈106GeV. • Scalar masses ≈105GeV. • At low energy, all the scalars decouple (split SUSY). • There is no SUSY flavor & CP problems in this model. SUSY 08, Korea

10. Setup • Superpotential (I have already shown): • SUSY breaking terms: • We adopt the “Z’-mediated SUSY breaking”. • Z’ is identified as ZB-L in this work. • Only four input parameters ! =106GeV SUSY 08, Korea

11. Radiative B-L breaking • Running behavior for the soft-mass of the ∆1 is shown below. • m2△1 goes into the negative region and develops a VEV. • Seesaw scale MN≈‹∆1› are generated dynamically. ≈ 105GeV~106GeV Only the B-L gaugino acquires its mass≈106GeV at Λs=109GeV f=4 f=5 f=6 f=7 ∆1 scalar acquire its mass through the RGE. SUSY 08, Korea

12. Gaugino Masses • Running behavior is shown below, where Λs=109GeV and gB-L=0.5 at μ=Λs. • Mass spectra are much different from mSUGRA (1:2:7) ! • The signals at the LHC experiments are rather exotic and interesting. Only the B-L gaugino acquires its mass≈106GeV at Λs=109GeV gluino wino bino B-L gaugino and all scalars decouples here! SUSY 08, Korea

13. Summary • Radiative B-L symmetry breaking works in a framework of Z’-mediation. • The mass spectra for gauginos are much different from mSUGRA. • U(1)B-L extension is fascinating. SUSY 08, Korea

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15. Back up SUSY 08, Korea

16. Gaugino Masses • Running behavior is shown below, where Λs=109GeV and gB-L=0.5 at μ=Λs. • Mass spectra are much different from mSUGRA (1:2:7) ! • The signals at the LHC experiments are rather exotic and interesting. Only the B-L gaugino acquires its mass≈106GeV at Λs=109GeV gluino wino bino B-L gaugino and all scalars decouples here! SUSY 08, Korea

17. Gaugino Masses (2) • Gaugino masses as a function of the boundary value of gB-L. • Gaugino masses as a function of Λs. gluino wino bino Λs is set to109GeV. gluino wino bino gB-L is set to 0.5 at μ=Λs. SUSY 08, Korea

18. Summary • U(1)B-L extension is fascinating. • Existence of RH neutrinos makes U(1)B-L gaugeable. • U(1)B-L symmetry forbids B and L violating terms. • Seesaw scale can be understood as the breaking scale of U(1)B-L. • U(1)B-L extended MSSM with Z’-mediation gives characteristic mass spectra. • All the sfermion masses become very heavy (~105 GeV). • The mass spectra for gauginos are much different from mSUGRA. • Radiative B-L symmetry breaking works in a framework of Z’-mediation. SUSY 08, Korea

19. Brief Review of the U(1)B-L extended MSSM(4) • Three features which I have shown • Existence of RH neutrinos makes U(1)B-L gaugeable. • U(1)B-L symmetry forbids B and L violating terms. • Seesaw scale can be understood as the breaking scale of U(1)B-L are enough reason to study the gauged U(1)B-L. • I will show the radiative U(1)B-L symmetry breaking works and the mass spectra is characteristic in a framework of “Z’-mediated SUSY breaking”. SUSY 08, Korea