Lepton Number Violation and the Baryon Asymmetry of the Universe Julia Harz ILP / LPTHE Paris ACFI Workshop, 29.03.2018 F . Deppisch, L. Graf, JH, W. Huang, arxiv:1711.10432 F . Deppisch, JH, W. Huang, M. Hirsch, H. Päs, Phys. Rev. D92 (2015) 036005 F . Deppisch, JH, M. Hirsch, PRL 112 (2014) 221601
How can we probe Baryogenesis models? 2 Julia Harz LNV and the Baryon Asymmetry of the Universe
Baryogenesis via Leptogenesis ● generation of lepton asymmetry via heavy neutrino decays ● competition with lepton number violating (LNV) washout processes ● conversion to baryon asymmetry via sphaleron processes at source of CP violation H L L H L N N N N N sphaleron processes H L H H L Q N L L N L L H H L H washout N H N N processes u Q H L L H u L H H scattering processes washout processes 3 Julia Harz LNV and the Baryon Asymmetry of the Universe
How can we test what generates the BAU? baryon asymmetry SM processes lepton asymmetry LHC washout Mechanism of processes CP violation neutrinoless double beta decay experiments 4 Julia Harz LNV and the Baryon Asymmetry of the Universe
LNV at 0vbb decay experiments 5 Julia Harz LNV and the Baryon Asymmetry of the Universe
Neutrinoless double beta decay (0vbb) Most stringent limits are currently from GERDA and Kamland-Zen: 6 Julia Harz LNV and the Baryon Asymmetry of the Universe
Neutrinoless double beta decay (0vbb) standard mass mechanism long range contribution short range contribution ? = Most stringent limits are currently from GERDA and Kamland-Zen: The inverse half life can be expressed in terms of efgective couplings: 7 Julia Harz LNV and the Baryon Asymmetry of the Universe
Neutrinoless double beta decay (0vbb) long range contribution Long range contribution: ? = Leptonic and hadronic current with difgerent chirality structure: with 8 Julia Harz LNV and the Baryon Asymmetry of the Universe
Possible underlying LNV operators standard mass mechanism long range contribution short range contribution ? = possibilities at tree level: possibilities at loop level: 9 Julia Harz LNV and the Baryon Asymmetry of the Universe
Constraining the efgective operator scale If 0vββ is observed, the scale of the underlying operator can be determined 10 Julia Harz LNV and the Baryon Asymmetry of the Universe
Lepton Asymmetry Washout ● LNV operator would cause washout of pre-existing net lepton asymmetry in the early Universe operator specifjc factor ● washout effjcient if lepton density If 0vßß is observed, washout effjcient in the temperature interval 11 Julia Harz LNV and the Baryon Asymmetry of the Universe
Impact on Baryogenesis models scale of operator scale above which a maximal lepton asymmetry of 1 is washout out to the observed baryon asymmetry (or less) scale above which washout is highly efgective If was observed via non-standard mechanism, resulting washout would rule out baryogenesis mechanisms above However: 0vßß decay probes only electron component of LNV operators: 12 Julia Harz LNV and the Baryon Asymmetry of the Universe
Extending the impact with LFV ● Most stringent limits on LFV set by 6-dim operators ● Determine interval in which LFV process equilibrate pre-existing fmavour asymmetry IF LFV processes are observed as well, loophole of asymmetry being stored in another fmavour sector is ruled out 13 Julia Harz LNV and the Baryon Asymmetry of the Universe
Distinguishing between difgerent operators ● SuperNEMO will be able to discriminate O 7 from others, due to e - R and e + L in the fjnal state ● potential discrepancy between neutrino mass (cosmology) and 0vbb half live measurement could be an indication for 0vbb triggered by non-standard mechanism ● distinguishing between difgerent mechanisms via measurements in difgerent isotopes ● observation of 0vββ via O 9 and O 11 will imply observation of LNV at LHC 14 Julia Harz LNV and the Baryon Asymmetry of the Universe
The full picture BUT: There are 129 LNV operators... 7-dim 9-dim 11-dim 15 Julia Harz LNV and the Baryon Asymmetry of the Universe
The full picture 7-dim 9-dim 11-dim 16 Julia Harz LNV and the Baryon Asymmetry of the Universe
Impact of sensitivity on efgective couplings 17 Julia Harz LNV and the Baryon Asymmetry of the Universe
The full picture 7-dim 9-dim 11-dim 18 Julia Harz LNV and the Baryon Asymmetry of the Universe
Competition between long- and short-range Short-range contribution: Long-range contribution: long short range range only first generation Yukawa couplings only only 19 Julia Harz LNV and the Baryon Asymmetry of the Universe
Competition between long- and short-range Short-range contribution: Long-range contribution: long short range range allow third generation Yukawa couplings only only 20 Julia Harz LNV and the Baryon Asymmetry of the Universe
The full picture 7-dim 9-dim 11-dim first generation only 21 Julia Harz LNV and the Baryon Asymmetry of the Universe
The full picture 7-dim 7-dim 9-dim 9-dim 11-dim 11-dim incl. third generation 22 Julia Harz LNV and the Baryon Asymmetry of the Universe
Comparison with mass mechanism first generation only 23 Julia Harz LNV and the Baryon Asymmetry of the Universe
Comparison with mass mechanism 7-dim 7-dim 9-dim 9-dim 11-dim 11-dim incl. third generation 24 Julia Harz LNV and the Baryon Asymmetry of the Universe
Validity of the efgective operator approach with 25 Julia Harz LNV and the Baryon Asymmetry of the Universe
LNV at the LHC 26 Julia Harz LNV and the Baryon Asymmetry of the Universe
LNV at the LHC signature: cross section in early universe determines washout strength cross section possibly measured at LHC Observable LNV signal at LHC and corresponding resonant mass can be directly related to baryon asymmetry washout 27 Julia Harz LNV and the Baryon Asymmetry of the Universe
LNV at the LHC ● Assuming pre-existing lepton asymmetry generated at high scale Observation of LNV process at the LHC implies a strong washout that it excludes leptogenesis models that generate an asymmetry above M x 28 Julia Harz LNV and the Baryon Asymmetry of the Universe
LNV at the LHC ● NOW: assumption that CP-asymmetry є is created at scale M N scale of CP-asymmetry generation scale of LNV observation observation of LNV process at the LHC ● excludes high-scale baryogenesis models ● sets lower limit on the baryon asymmetry of a low-scale leptogenesis model 29 Julia Harz LNV and the Baryon Asymmetry of the Universe
LNV at the LHC ● NOW: assumption that CP-asymmetry є is created at scale M N not possible to generate large enough baryon asymmetry at all lower limit on CP-asymmetry observation of LNV process at the LHC ● excludes high-scale baryogenesis models ● sets lower limit on the baryon asymmetry of a low-scale leptogenesis model 30 Julia Harz LNV and the Baryon Asymmetry of the Universe
Conclusions ● LNV processes are of high interest with respect to baryogenesis ● tight connection of high intensity and energy frontier ● possibility to falsify / probe BG models! 31 Julia Harz LNV and the Baryon Asymmetry of the Universe
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