An electroweak basis for neutrinoless double β decay
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Here, a discovery of neutrinoless double-β decay would be profound, providing the first direct experimental evidence of ΔL = 2 lepton number violating processes. While a natural explanation is provided by an effective Majorana neutrino mass, other new physics interpretations should be carefully evaluated. At low-energies such new physics could man-ifest itself in the form of color and SU(2)L × U(1)Y invariant higher dimension operators. Here we determine a complete set of electroweak invariant dimension-9 operators, and our analysis supersedes those that only impose U(1)em invariance. Imposing electroweak invariance implies: 1) a significantly reduced set of leading order operators compared to only imposing U(1)em invariance; and 2) other collider signatures. Prior to imposing electroweak invariance we find a minimal basis of 24 dimension-9 operators, which is reduced to 11 electroweak invariant operators at leading order in the expansion in the Higgs vacuum expectation value. We set up a systematic analysis of the hadronic realization of the 4-quark operators using chiral perturbation theory, and apply it to determine which of these operators have long-distance pion enhancements at leading order in the chiral expansion. We also find at dimension-11 and dimension-13 the electroweak invariant operators that after electroweak symmetry breaking produce the remaining ΔL = 2 operators that would appear at dimension-9 if only U(1)em is imposed.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- LDRD; USDOE
- Grant/Contract Number:
- AC52-06NA25396
- OSTI ID:
- 1398909
- Report Number(s):
- LA-UR--16-23550
- Journal Information:
- Journal of High Energy Physics (Online), Journal Name: Journal of High Energy Physics (Online) Journal Issue: 8 Vol. 2017; ISSN 1029-8479
- Publisher:
- Springer BerlinCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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