Why three generations?
Here, we discuss an anthropic explanation of why there exist three generations of fermions. If one assumes that the right-handed neutrino sector is responsible for both the matter-antimatter asymmetry and the dark matter, then anthropic selection favors three or more families of fermions. For successful leptogenesis, at least two right-handed neutrinos are needed, while the third right-handed neutrino is invoked to play the role of dark matter. The number of the right-handed neutrinos is tied to the number of generations by the anomaly constraints of the U(1)B-L gauge symmetry. Combining anthropic arguments with observational constraints, we obtain predictions for the X-ray observations, as well as for neutrinoless double-beta decay.
- Research Organization:
- Univ. of California, Los Angeles, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- SC0009937
- OSTI ID:
- 1253026
- Alternate ID(s):
- OSTI ID: 1285777
- Journal Information:
- Physics Letters B, Journal Name: Physics Letters B Vol. 758 Journal Issue: C; ISSN 0370-2693
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- Netherlands
- Language:
- English
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