Fakultät Mathematik und Naturwissenschaften, Institut für Kern- und Teilchenphysik Various new measurements related to DBD Kai Zuber Institute for Nuclear- and Particle Physics 23.9. 2017, Erice 2017

Contents Introduction Nuclear matrix elements (exp.) Quenching of gA I‘m sure you‘ve heard it all before - Oasis Introduction Nuclear matrix elements (exp.) Quenching of gA Excited states and double EC Charged lepton flavour violation Summary

Double EC and DBD Mass parabola (isobar) There are 35 double beta (and ECEC) emitters out of which 6 are double positron emitters Depending on Q-value competing with double Positron and EC/positron decay - Both modes can occur with/without neutrinos - Also transitions into excited states are possible

Master equation 1 / T1/2 = PS * NME2 * (<m> / me)2 Measurement Nuclear Physics Measurement Exact calculation Complex calculations Quantity of interest Severe nuclear structure issue J. Kotila, F. Iachello, PRC 034316 (2012) S. Stoica, M. Mirea, arXiv:1307.0290

Several new techniques applied in last years Matrix element Rescaled as people use different gA (1-1.25) and R0 (1.0-1.3 fm) would do it A. Dueck, W. Rodejohann, K. Zuber, arXiv:1103.4152, PRD 83, 113010 (2011) Several new techniques applied in last years

Supportive measurements Working packages Precise Q-value measurements Charge exchange reactions Ordinary muon capture Double electron captures Neutrino-Nucleus scattering Nucleon transfer reactions Consensus Report: K. Zuber, nucl-ex/0511009

NME – Intermediate states 1+ states up to about Q-value All multipoles up to about 100 MeV

Experimental approaches 0nbb decay rate scales with Q5 only those with Q>2000 keV 11 isotopes of interest Isotope Nat. abund. (%) Q-values 2016 Ca-48 0.187 4262.96 ± 0.84 Ge-76 7.44 2039.006 ± 0.050 Se-82 8.73 2997.9 ± 0.3 Zr-96 2.80 3356.097 ± 0.086 Mo-100 9.63 3034.40 ± 0.17 Pd-110 11.72 2017.85 ± 0.64 Cd-116 7.49 2813.50 ± 0.13 Sn-124 5.79 2292.64 ± 0.39 Te-130 33.80 2527.518 ± 0.013 Xe-136 8.9 2457.83 ± 0.37 Nd-150 5.64 3371.38 ± 0.20 Candles GERDA, Majorana, LEGEND SuperNEMO, LUCIFER MOON, AMore COBRA Tin.Tin CUORE, SNO+, CuPID nEXO, KamLAND-Zen, NEXT, XMASS MCT, SuperNEMO(?) All Q-values measured to an error of less than 1 keV!

Charge exchange reactions 128,130Te(3He,t)128,130I Best resolution at RCNP Osaka using Grand Raiden spectrometer P, Puppe et al. PRC 86, 044603 (2012) Double charge exchange reactions -> Talk by H. Lenske

Neutrino-less DBD How to probe high lying excitations? Courtesy H. Lenske How to probe high lying excitations?

Ordinary muon capture D. Zinatulina, MEDEX 2017

Nucleon transfer reactions J. Schiffer et al. , PRL 2008

Deformation Not all nuclei are spherical...

Quenching of gA Deppisch, Suhonen, arXiv:1606.02908

The case of 113Cd 4-fold forbidden non-unique beta decay (1/2+9/2+) COBRA double beta decay experiment (64 CdZnTe detectors) Q-value: 113Cd Preliminary J. V. Dawson et al., Nucl. Phys. A 818,264 (2009) AME 2012 value: 322.6 0.8 keV Penning trap value: 323.89 (27) keV N. D. Gamage et al., Phys. Rev. C 94,025505 (2016) Shape depends on gA M. T. Mustonen, M. Aunola, J. Suhonen , PRC 73,054301 (2006) M. T. Mustonen, J. Suhonen,, PLB 657,38 (2007) Status: COBRA modified for low threshold, data taking has started end of july

Excited state transitions First excited 0+ states have only been seen in Mo-100 and Nd-150 GERDA phase I : First (and only) multi-detector analysis in GERDA Die blauen Baender sind Seitenbaender fuer die Background estimation T^ M. Agostini et al., J. Phys. G 42. 115201 (2015)

Excited state transitions More measurements : „Our“ measurements J. Phys. G 43,115201 (2016) More half-life limits exist but most of them are below 1020 years

Double EC and DPD Theory predictions are lacking for neutrinoless double EC: - Internal bremsstrahlungs gamma (monoenergetic) Pair production in nuclear field Internal conversion M. Doi, T. Kotani, Prog. Theo. Phys. 89,130 (1993) (GERDA and „our“ measurements) Eur. Phys. J C 76, 652 (2016) Again more measurements exist NB: Q-value is reduced by 2mec2 for a positron

2nu double EC Suggestion: Use LXe dark matter detectors for search (124,126Xe) N. Barros, J. Thurn, K. Zuber, J. Phys. G 41, 115105 (2014) Xenon-collab: T > 6.5 1020 years, (124Xe) Phys. Rev. C 95, 024605 (2017) XMASS-collab.: T > 4.7 1021 years (124Xe) T > 4.3 1021 years (126Xe) , Phys. Lett. B 759,64 (2016) Russian collab.: T > 2.1 1021 years (124Xe), Phys. Part. Nucl. 48, 38 (2017) More to come - more data, larger detectors like DARWIN and others

Charged lepton flavour violation (CLFV) DBD limits have improved by about a factor 10 in 15 years (optimistic) If you want to have fun: Factor 10000 in 8 years Mu2e Focus: Coherent muon – electron conversion on nuclei (coherent = via ground state)

CLFV Aim : R about 10-17

(My) Questions  What fraction in muon-electron conversion is mediated via excited states (GDR)? Thanks Petr, Alex This would be most interesting for Aluminum (COMET, Mu2e) How does this depend on the element/nucleus, i.e. target?    Could there be spin dependent and spin independent reactions like in dark matter? See Phys. Lett. B 771, 242 (2017)

Total lepton number violation  Neutrino-less double beta decay  μ- - e+ conversion on nuclei T. Geib, A. Merle, K. Zuber, PLB 764,157 (2017)  Neutrino-less double muon decay of the kaon (< 8.6 x 10-11) K. Zuber, Phys. Lett. B 479,33 (2000) J. Barley et al., Phys. Lett. B 769,67 (2017) In general: BSM physics

COMET Major aim: coherent muon-electron conversion on nuclei (CLFV), will be performed at J-PARC, start 2019 Phase 1 setup: Which would be best target for μ- - e+ ? Major background: Radiative muon capture Phase I: Improvement of factor 100, Phase 2: Another factor 100 B. Yeo, Y. Kuno, M. Lee, K. Zuber, arxiv:1705.07464, acc. PRD

Summary Q-values for all relevant DBD isotopes are measured with less than a keV uncertainty More measurements have been obtained or will be persuit (3He,t), OMC, nucleon transfer reactions..) to provide good date for NME calculations Spectral shape searches in highly forbidden beta decay sounds interesting for learning about quenching of gA Various new half-lives for excited states in double beta decay and radiative double EC have been obtained  Big progess expected in the next years in charged lepton flavour violation processes