University College London. Frank Deppisch. University College London

Transcription

1 Frank Deppisch University College London BLV 2017 Case Western Reserve U May 2017

2 Origin of neutrino masses beyond the Standard Model Two possibilities to define neutrino mass Dirac mass analogous to other m fermions but with ν ΛEW couplings to Higgs Majorana mass, using only a left-handed neutrino Lepton Number Violation Y ν ν L ν R ν L H Y ν H ν L H H ν L 2 / 21 Frank Deppisch 0nbb Theory 18/5/2017

3 Single beta decay A, Z A, Z e + ҧ ν e Allowed double beta (2νββ) decay A, Z A, Z e + 2 ҧ ν e Neutrinoless double beta (0νββ) decay A, Z A, Z e Violation of lepton number Mediated by Majorana neutrinos Variants 0νβ + β + : A, Z A, Z 2 + 2e + 0νβ + EC: A, Z + e A, Z 2 + e + 0νECEC: A, Z + 2e A, Z 2 Majoron-assisted 0νββ decay A, Z A, Z e + nχ 3 / 21 Frank Deppisch 0nbb Theory 18/5/2017

4 Half-life T 1 1/2 = m ββ 2 G 0ν M 0ν 2 Particle Physics q 100 MeV 3 A lep μν = 1 4 i=1 2 q + m νi γ μ 1 + γ 5 q 2 2 m γ ν 1 γ 5 γ μ 1 + γ 5 γ ν νi 4q 2 U ei 3 i=1 U 2 ei m νi m ββ Atomic Physics Leptonic phase space G 0ν Nuclear Physics Nuclear transition matrix element M 0ν T 1 1/2 m ββ 2 q 4 G 4 F Q yr m ββ T 1/2 ev 2 Q 2 4 MeV 4 / 21 Frank Deppisch 0nbb Theory 18/5/2017

5 Effective 0νββ Mass m ββ = c 2 12 c 2 13 m ν1 + s 2 12 c 2 13 m ν2 e iφ 12+s 2 13 m ν3 e i(φ 13 2δ) Degenerate Regime m ββ = m ν 1 sin 2 (2θ 12 )sin 2 φ 12 2 KamLAND-Zen upper limit Phys. Rev. Lett. 117 (2016) Uncertainty from unknown Majorana phases Accidental cancellation for NH possible Dell'Oro, Marcocci, Viel, Vissani, Adv.High Energy Phys. (2016) / 21 Frank Deppisch 0nbb Theory 18/5/2017

6 Effective 0νββ Mass m ββ = c 2 12 c 2 13 m ν1 + s 2 12 c 2 13 m ν2 e iφ 12+s 2 13 m ν3 e i(φ13 2δ) + s 2 14 m ν4 e iφ 14 + Dependence on new mass, mixing, phase Guzowski et al., Rodejohann, Phys. Rev. D 92 (2015) Int.J.Mod.Phys. E20 (2011) / 21 Frank Deppisch 0nbb Theory 18/5/2017

7 Hadronic current J μ q = g V γ μ g A γ μ γ 5 + ig M 2m N σ μν q ν g P γ 5 q μ Nuclear Matrix Element M 0ν M 0ν = g A 2 M GT g V 2 g A 2 M F + M T Many-body problem Factor 2 3 uncertainty between nuclear models Menendez, arxiv: Iwata et al., Phys. Rev. 7 / 21 Frank Deppisch 0nbb Theory 18/5/2017 Lett. 116,

8 Nuclear matrix element M 0ν = g A 2 M GT g V 2 g A 2 M F + M T Axial-vector coupling g A Free nucleon: g A 1.27 Comparison of β and 2νββ decay with theory: g A If applicable to 0νββ, reduction of sensitivity Genuine effect or short-coming of models? Iachello 16 8 / 21 Frank Deppisch 0nbb Theory 18/5/2017

9 Comparison with measured single beta / electron capture rates Fit of model parameters g A i and g pp (per even-even isotope) 6147 log ft = log 10 f 0 t 1Τ2 s = log 10 B GT B GT = g A 2 2J + 1 M GT(g pp, g ph 2 FFD, Suhonen, Phys. Rev. C 94 (2016) 5, / 21 Frank Deppisch 0nbb Theory 18/5/2017

10 Comparison with measured single beta / electron capture rates Fit of model parameters g A i and g pp (per even-even isotope) Taking into account all isotopes Comparison with 2νββ Quenching of g A (mass number dependent), including large errors FFD, Suhonen, Phys. Rev. C 94 (2016) 5, / 21 Frank Deppisch 0nbb Theory 18/5/2017

11 Single beta / EC / 2νββ analysis relevant for 0νββ? 11 / 21 Frank Deppisch 0nbb Theory 18/5/2017

12 Single beta / EC / 2νββ analysis relevant for 0νββ? Processes different at nucleon level Probing different transitions Incorporate more experimental information Higher, forbidden beta decays Charge exchange reactions Muon capture 12 / 21 Frank Deppisch 0nbb Theory 18/5/2017

13 Single beta / EC / 2νββ analysis relevant for 0νββ? Processes different at nucleon level Probing different transitions Incorporate more experimental information Higher, forbidden beta decays Charge exchange reactions Muon capture 13 / 21 Frank Deppisch 0nbb Theory 18/5/2017

14 Plethora of New Physics scenarios d u 0nbb e e d u T 1 1Τ2 = ε 2 NP G 0ν 0ν NP M 2 NP Left-Right Symmetry R-Parity Violating SUSY Extra Dimensions Majorons Leptoquarks 14 / 21 Frank Deppisch 0nbb Theory 18/5/2017

15 Plethora of New Physics scenarios d u 0nbb e e d u T 1 1Τ2 = ε 2 NP G 0ν 0ν NP M 2 NP Left-Right Symmetry Neutrinos still Majorana Extra Dimensions Majorons R-Parity Violating SUSY Leptoquarks 15 / 21 Frank Deppisch 0nbb Theory 18/5/2017

16 Examples in Left-Right Symmetry d u d 0nbb e e u T 1 1Τ2 = ε 2 NP G 0ν 0ν NP M 2 NP 0νββ probes the TeV scale 3 ε RRz 2 3 = V m p m W ei m 4 N i= ( ΛΤ1 TeV) 5 4 m WR 3 ε V+A V A = U ei W ei tan ζ W i= ( ΛΤ10 TeV) 3 16 / 21 Frank Deppisch 0nbb Theory 18/5/2017

17 Examples in Left-Right Symmetry d u d 0nbb e e u T 1 1Τ2 = ε 2 NP G 0ν 0ν NP M 2 NP 0νββ probes the TeV scale 3 ε RRz 2 3 = V m p m W ei m 4 N i= ( ΛΤ1 TeV) 5 Modified angular and energy distribution of emitted electrons (Doi et al. '83; Ali et al. '06) 4 m WR 3 ε V+A V A = U ei W ei tan ζ W i= ( ΛΤ10 TeV) 3 FFD, SuperNEMO, Eur.Phys.J. C70 (2010) 927) 17 / 21 Frank Deppisch 0nbb Theory 18/5/2017

18 Generic Tree-level Topologies for 0νββ 9-dim Operator Comparison between 0νββ and LHC Heavy LHC Wilson running and pion contributions for 0νββ Comparable sensitivity Mahajan, Phys.Rev.Lett. 112 (2013) ; Helo, Hirsch, Kovalenko, Päs, Phys.Rev. D88 (2013) ; Gonzalez, Hirsch, Kovalenko, Phys.Rev. D93 (2016), ; Peng, Ramsey-Musolf, Winslow, Phys.Rev. D93 (2016) s = 14 TeV Peng, Ramsey-Musolf, Winslow / 21 Frank Deppisch 0nbb Theory 18/5/2017

19 Classic Example: High-Scale Leptogenesis Generation via heavy neutrino decays Competition with LNV washout processes Conversion to baryon asymmetry EW sphaleron processes at T 100 GeV Observed asymmetry η B n B n തB n γ = (6.20 ± 0.15) What if we observe lepton number violating processes in 0ννβ? 19 / 21 Frank Deppisch 0nbb Theory 18/5/2017

20 Compare 0νββ rate with lepton asymmetry washout in the early Universe Observation of lepton number violation gives information at what temperatures operators are in equilibrium corresponds to highly effective washout Γ W /H 1 can falsify high-scale baryogenesis scenarios FFD, Harz, Hirsch, Huang, Päs, Phys.Rev. D92 (2015) Br(μ eγ) Br(τ lγ) R(μ e) 20 / 21 Frank Deppisch 0nbb Theory 18/5/2017

21 Neutrinos much lighter than other fermions Dirac or Majorana? Lepton Number Violation? Mechanism of neutrino mass generation? At what scale? 0νββ is crucial probe for BSM physics Discovery Majorana n Physics near GUT scale? TeV? Exclusion Dirac n? Fine-tuned SM? Challenging nuclear physics Strong Synergy with LHC+LFV searches LHC can deep-probe anatomy of 0νββ LNV operators Observation of LNV+LFV would strongly constrain baryogenesis 21 / 21 Frank Deppisch 0nbb Theory 18/5/2017