Neutrinoless ββ decay and direct dark matter detection

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1 Neutrinoless ββ decay and direct dark matter detection Javier Menéndez Center for Nuclear Study, The University of Tokyo INT workshop From nucleons to nuclei: enabling discovery for neutrinos, dark matter and more Institute for Nuclear Theory, 26 th June 2018

Nuclear physics, ββ decay, dark matter detection Nuclear structure crucial for design and interpretation of experiments Neutrinos, dark matter studied in low-energy experiments using nuclei Abundant

2 Nuclear physics, ββ decay, dark matter detection Nuclear structure crucial for design and interpretation of experiments Neutrinos, dark matter studied in low-energy experiments using nuclei Abundant material, long observation time with very low background sensitive to rarest decays and tiny cross-sections! 0νββ decay: Dark matter: ( T 0νββ 1/2 dσ χn dq 2 ) 1 M 0νββ 2 m 2 ββ 2 c i ζ i F i i M 0νββ : Nuclear matrix element F i : Nuclear structure factor Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 2 / 44

Nuclear matrix elements and structure factors Nuclear matrix elements needed to study fundamental symmetries Final L leptons nucleons Initial = Final dx j µ (x)j µ (x) Initial Nuclear structure

3 Nuclear matrix elements and structure factors Nuclear matrix elements needed to study fundamental symmetries Final L leptons nucleons Initial = Final dx j µ (x)j µ (x) Initial Nuclear structure calculation of the initial and final states: Quantum Monte Carlo, no-core shell model, coupled cluster shell model, energy density functional Lepton-nucleus interaction: Evaluate (non-perturbative) hadronic currents inside nucleus: phenomenology, effective theory CDMS Collaboration Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 3 / 44

4 Outline 1 Lepton number violation, neutrino nature: neutrinoless ββ decay 2 Direct detection of dark matter: dark matter scattering off nuclei 3 Summary Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 4 / 44

5 Outline 1 Lepton number violation, neutrino nature: neutrinoless ββ decay 2 Direct detection of dark matter: dark matter scattering off nuclei 3 Summary Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 /

β - β - 76 Br β + β + 76 Kr 76 Se -76 30 31 32 33 34 35 36 37 Atomic number, Z Best limits: 76 Ge (GERDA), 130 Te

6 Neutrinoless ββ decay Lepton-number violation, Majorana nature of neutrinos Second order process only observable in rare cases with β-decay energetically forbidden or hindered by J Ga Binding energy (MeV) β - 76 As 76 Ge β - β - 76 Br β + β + 76 Kr 76 Se Atomic number, Z Best limits: 76 Ge (GERDA), 130 Te (CUORE), 136 Xe (EXO, KamLAND-Zen) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 5 / 44

7 Next generation experiments: inverted hierarchy The decay lifetime is T 0νββ 1/2 ( ) 1 = G01 M 0νββ 2 m 2 ββ sensitive to absolute neutrino masses, m ββ = U 2 ek m k, and hierarchy 1 Ca Se Zr Cd Te Nd Te Ge Mo (ev) 1 10 Xe m IH NH (ev) m lightest A Matrix elements needed to make sure KamLAND-Zen, PRL (2016) next generation ton-scale experiments fully explore "inverted hierarchy" Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 6 / 44

8 0νββ decay nuclear matrix elements Large difference in nuclear matrix element calculations: factor f τn τm H X (r) Ω X 0 + Ω X = Fermi (1), GT (σ nσ m),tensor i H(r) = neutrino potential n,m M 0ν X NR-EDF R-EDF QRPA Jy QRPA Tu QRPA CH IBM-2 SM Mi SM St-M,Tk VMC A Ab initio quantum Monte Carlo 0νββ: Pastore et al. PRC (2018) Phenomenological many-body: shell model, energy-density functional theory, QRPA... Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 7 / 44

9 Shell model Solve many-body problem by direct diagonalization in limited configuration space Excluded orbitals: always empty Valence space: configuration space where to solve the many-body problem Inner core: always filled Diagonalize valence space, other effects in H eff : H Ψ = E Ψ H eff Ψ eff = E Ψ eff Ψ eff = α c α φ α, φ α = a + i1 a+ i2...a+ ia 0 Exact diagonalization: dimension Caurier et al. RMP (2005) Monte Carlo shell model: dimension Togashi et al. PRL (2016) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 8 / 44

10 Shell model configuration space: spectra For 48 Ca enlarge shell model configuration space from pf to sdpf (4 to 7 orbitals) restricted to 2 ω excitations dimension of 48 Ti calculation increases from less than 10 6 to over 10 9 Excitation Energy (MeV) (+) Ca Exp SDPFMU-db Ti Exp. Iwata et al. PRL (2016) SDPFMU-db The state in 48 Ca is brought down by 1.3 MeV in the sdpf calculation Good agreement to experiment and with the associated two-proton transfer cross section (2 ω states dominant in 48 Ca ) The difference in the 48 Ca two-neutrino ββ decay matrix element is about 5% between pf and sdpf calculations Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 9 / 44

11 Shell model matrix elements in two shells 48 Ca 48 Ti 0νββ decay Enlarge configuration space from pf to sdpf, 4 to 7 orbitals Test excitation energy of in 48 Ca off by 1.3MeV in pf shell NME Ca 0 QRPA IBM EDF SM SM SM (pf) (MBPT) (sdpf) Nuclear matrix element increases moderately 30% Iwata et al. PRL (2016) Likewise, very mild effect found in GCM calculations of 76 Ge Jiao et al. PRC (2017) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

12 Pairing correlations and 0νββ decay 0νββ decay favoured by proton-proton, neutron-neutron pairing, but it is disfavored by proton-neutron pairing M 0νββ Ideal case: superfluid nuclei reduced with high-seniorities A=48 A=76 A=82 A=124 A=128 A=130 A= s m Caurier et al. PRL (2008) M 0ν Addition of isoscalar pairing reduces matrix element value GCM SkO QRPA SkO GCM SkM* QRPA SkM* g T =0 /ḡ T =1 Hinohara, Engel PRC (2014) Related to approximate SU(4) symmetry of the H(r)σ i σ j τ i τ j operator Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

13 Gamow-Teller β decay: quenching Gamow-Teller β decays described well by nuclear structure (shell model) but n W F i g eff A p e ν σ iτ i I T(GT) Exp g eff A = qg A, q T(GT) Th. Martínez-Pinedo et al. PRC (1996) Theory needs to quench στ operator to reproduce experimental lifetimes: problem in nuclear many-body wf or operator? This puzzle has been the target of many theoretical efforts: Arima, Rho, Towner, Bertsch and Hamamoto, Wildenthal and Brown... Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

14 Ab initio many-body methods Oxygen dripline using chiral NN+3N forces correctly reproduced ab-initio calculations treating explicitly all nucleons excellent agreement between different approaches No-core shell model (Importance-truncated) In-medium SRG Hergert et al. PRL (2013) Self-consistent Green s function Cipollone et al. PRL (2013) Coupled-clusters Jansen et al. PRL (2014) Energy (MeV) obtained in large many-body spaces MR-IM-SRG IT-NCSM SCGF Lattice EFT CC AME Mass Number A Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

15 Chiral effective field theory Chiral EFT: low energy approach to QCD, nuclear structure energies Approximate chiral symmetry: pion exchanges, contact interactions Systematic expansion: nuclear forces and electroweak currents 2N force 3N force 4N force N e ν LO NLO N N N e ν N N e ν 2 N LO π N N N N 3 N LO Weinberg, van Kolck, Kaplan, Savage, Epelbaum, Kaiser, Meißner... Park, Baroni, Krebs... 2b currents applied to νd scattering (SNO), 3 H β-decay, µ moment... Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

16 2b currents in medium-mass nuclei Normal-ordered 2b currents modify GT operator JM, Gazit, Schwenk PRL (2011) N N e ν J eff n,2b g Aρ fπ 2 [ τn σ n I(ρ, P) (2c ] 4 c 3 ) 3 g Aρ fπ 2 τn 2 σ n 3 c 3 p 2 m 2 π + p 2, π 1.1 1bc N N p=0 2bc p [MeV] ρ [fm -3 ] 2b currents predict g A quenching q = Quenching reduced at p > 0, relevant for 0νββ decay where p m π Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44 GT(1b+2b)/g A bc 1bc

17 β decay in very light nuclei: GFMC vs NCSM Quantum Monte Carlo, No Core Shell Model β decays in A 10 G. Hagen, J. Holt, P. Navrátil et al. INT-18-1a program, Pastore et al. PRC (2018) Very good agreement to experiment, except 10 C (structure) Impact of 2b currents small (few %), disagreement on sign Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

18 β decay in medium-mass nuclei: IMSRG Quenching of g A in Gamow-Teller Decays VS-IMSRG calculations of GT transitions in sd, pf shells Minor effect from consistent effective operator Significant effect from neglected 2-body currents Ab initio calculations explain data with unquenched g A From J. Holt, INT-18-1a program Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

19 Short-range correlations Pair correlations of quantum Monte Carlo calculations approximated by combination of short- and long-range parts ρ NN (r) = a ρ contact NN (r) + b ρ (0) NN (r) Correlation function defined by ρ NN (r) F (r) = ρ uncorrelated NN (r) Cruz-Torres et al. arxiv: Impact on 0νββ decay nuclear matrix elements small 10% Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

Open questions: transition operator Contact light-neutrino operator Two-body currents in ββ decay Cirigliano et al. PRL120 202001(2018) Unknown coupling value E.

20 Open questions: transition operator Contact light-neutrino operator Two-body currents in ββ decay Cirigliano et al. PRL (2018) Unknown coupling value E. Mereghetti s talk Short-range character (r) (fm 1 ) r (fm) Estimated effect 10% Wang et al. arxiv:1805:10276 compared to 20% in GT β decay ( quenching ) JM et al. PRL (2011) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

Tests of nuclear structure Test of 0νββ decay: comparison of predicted 2νββ decay vs data, momentum transfers q 100 MeV: µ-capture, inelastic ν scattering Shell model reproduce 2νββ data including

21 Tests of nuclear structure Test of 0νββ decay: comparison of predicted 2νββ decay vs data, momentum transfers q 100 MeV: µ-capture, inelastic ν scattering Shell model reproduce 2νββ data including quenching common to β decays in same mass region Shell model prediction previous to 48 Ca measurement! M 2νββ = k 0 + f n σnτ n 1 + k 1 + k E k (M i + M f )/2 m σmτ m 0 + i µ-capture, ν-nucleus scattering many multipoles (J values), like 0νββ decay Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

22 Gamow-Teller strength distributions Gamow-Teller (GT) strength distributions well described by theory (quenched) Iwata et al. JPSCP (2015) Freckers et al. NPA (2013) 1 + f i dσ dω (θ = 0) i A σ iτ ± 0 + gs, g eff i g eff A σ i τ ± 0.7g A GT strengths combined related to 2νββ decay, but relative phase unknown Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

23 Double Gamow-Teller strength distribution Measurement of Double Gamow-Teller (DGT) resonance in double charge-exchange reactions 48 Ca(pp,nn) 48 Ti proposed in 80 s Auerbach, Muto, Vogel s, 90 s Recent experimental plans in RCNP, RIKEN ( 48 Ca), INFN Catania Takaki et al. JPS Conf. Proc (2015) Capuzzello et al. EPJA (2015), Takahisa, Ejiri et al. arxiv: Promising connection to ββ decay, two-particle-exchange process, especially the (tiny) transition to ground state of final state Shell model calculation Shimizu, JM, Yako, PRL (2018) B(DGT 1 48 [ ; λ; i f ) = 2J i + 1 Ti σ i τ i i j B(DGT) SDPFMU J=2 SDPFMU J=0 GXPF1B J=2 GXPF1B J= Ex. (MeV) ] (λ) σ j τ 2 j 48Ca gs Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

24 DGT and 0νββ decay: heavy nuclei M DGT (0 + gs 0+ gs ) M DGT (0 + gs 0+ gs ) 1.2 Ca (a) Ti 1 Cr KB3G 0.8 GXPF1B EDF Ge Se Sn Te Xe EDF QRPA (b) M 0νββ (0 + gs 0+ gs ) DGT transition to ground state M DGT = B(DGT ; 0; 0 + gs 0 + gs) very good linear correlation with 0νββ decay nuclear matrix elements Correlation holds across wide range of nuclei, from Ca to Ge and Xe Common to shell model and energy-density functional theory 0 M 0νββ 5 disagreement to QRPA Shimizu, JM, Yako, PRL (2018) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

25 Short-range character of DGT, 0νββ decay Correlation between DGT and 0νββ decay matrix elements explained by transition involving low-energy states combined with dominance of short distances between exchanged/decaying neutrons Bogner et al. PRC (2012) C GT (r jk ) [fm -1 ] DGT 0νββ decay (a) (b) 136 Xe r jk [fm] q [MeV] C GT (q) [MeV -1 ] 0νββ decay matrix element limited to shorter range Short-range part dominant in double GT matrix element due to partial cancellation of mid- and long-range parts Long-range part dominant in QRPA DGT matrix elements Shimizu, JM, Yako, PRL (2018) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

26 Outline 1 Lepton number violation, neutrino nature: neutrinoless ββ decay 2 Direct detection of dark matter: dark matter scattering off nuclei 3 Summary Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 /

27 Dark matter: evidence Solid cosmological evidence for existence of dark matter in very different observations: Rotation curves, Lensing, CMB... Zwicky 1930 s, Rubin 1970 s..., Planck 2010 s Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

Direct detection of dark matter Challenge: direct detection of dark matter in the laboratory to understand its nature / composition Assume dark matter (WIMPs) interact with quarks, gluons direct

28 Direct detection of dark matter Challenge: direct detection of dark matter in the laboratory to understand its nature / composition Assume dark matter (WIMPs) interact with quarks, gluons direct detection possible via scattering off nuclear targets International collaborations: XENON, LUX, PANDA-X, CDMS... measure nuclear recoils from WIMP-nucleus scattering sensitive to m χ 1 GeV Theory: most efficient analysis of experiments covering widest range of WIMP-nucleus interactions χ χ SM SM Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

Direct dark matter detection exclusion plots Present experiments show no evidence for dark matter, in spite of some unconfirmed claims Exclusion plots restrict dark matter coupling to Standard Model

29 Direct dark matter detection exclusion plots Present experiments show no evidence for dark matter, in spite of some unconfirmed claims Exclusion plots restrict dark matter coupling to Standard Model fields XENON Coll. PRL (2017) XENON Coll. PRL (2012) Standard analyses consider simplest spin-independent (scalar-scalar) and sometimes spin-dependent (axial-axial) isovector couplings Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

Particle, hadronic and nuclear physics WIMP scattering off nuclei interplay of particle, hadronic and nuclear physics: WIMPs: interaction with quarks and gluons Quarks and gluons: embedded in the

30 Particle, hadronic and nuclear physics WIMP scattering off nuclei interplay of particle, hadronic and nuclear physics: WIMPs: interaction with quarks and gluons Quarks and gluons: embedded in the nucleon Nucleons: form complex, many-nucleon nuclei General WIMP-nucleus scattering cross-section: dσ χn dq 2 ζ: kinematics (q 2, ) 2 c i ζ i F i i c coefficients: WIMP couplings to quark, gluons (Wilson coefficients), particle physics convoluted with hadronic matrix elements, hadronic physics F functions: F 2 structure factor, nuclear structure physics Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

31 Nuclear structure for xenon For xenon, phenomenological shell model (part of the) nuclear interaction adjusted to nuclei in same mass region Energy (kev) / /2 - Xe 7/ /2 7/2 + (1/2,3/2) /2 5/2 + 9/ /2-11/ / /2 1/2 + 0 Th Exp Theory JM, Gazit, Schwenk PRD (2012) Vietze, Klos, JM, Haxton, Schwenk PRD (2015) Excitation energy (kev) Xe Exp & Agreement to experimental excitation spectra very good Calculations with 5 orbitals for protons, neutrons: max dimenstion 4*10 8 Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

32 Nuclear structure for xenon For xenon, phenomenological shell model (part of the) nuclear interaction adjusted to nuclei in same mass region Energy (kev) /2 + 7/2-7/2 + 5/2 + 9/2-131 Xe 7/2-7/2 + (1/2,3/2) + 5/2 + 9/ / Th 11/2-1/2 + Exp 1/2 + JM, Gazit, Schwenk PRD (2012) Vietze, Klos, JM, Haxton, Schwenk PRD (2015) arxiv: Agreement to experimental excitation spectra very good Calculations with 5 orbitals for protons, neutrons: max dimenstion 4*10 8 Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

33 Nuclear structure for dark matter scattering targets Similar level of agreement in other light / medium-mass nuclei studied Excitation energy (kev) /2 + 7/ /2 + 7/2 + 1/2 + 5/ /2 + 7/2 + 9/2 + 7/2 + 5/2 + 1/2 + 9/2 + 7/2 + 5/2 + 5/ F 29 + Si 5/2+ 5/2 1/2 + 1/2 + 1/2 + Theory Exp. Theory Exp. 7/2 + 5/2 + 1/2 + 9/2 + 7/2 + 5/2 + 5/2 + 1/2 + Excitation energy (kev) Theory Ar Exp Excitation energy (kev) Theory 9/2 + (5/2,7/2) - 1/2 + (5/2-13/2) + 5/2 + 7/2 + 3/2-3/2 - (5/2) - (7/2) + 5/2 + 1/2-9/2 + 11/ /2 Ge - 7/2 + 1/2-5/2 + 5/2-5/2 + 3/2-9/2 + 7/2 + 1/2-9/2 + Exp Excitation energy (kev) Ge (3,4) (0 + ) Theory Exp. Theory Exp Ge (1,2) (1,2) + (3 - ) (1,2) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

34 WIMP scattering off nuclei: standard analysis Standard direct detection analyses consider two very different cases Spin-Independent (SI) interaction: WIMPs couple to the nuclear density (1 χ 1 N ) For elastic scattering, coherent sum over nucleons and protons in the nucleus Cross section enhancement by factor A N 1 N N 2 = A 2 S S (u) Structure factor Fit 130 Xe Spin-Dependent (SD) interaction: WIMP spins couple to the nuclear spin (S χ S N ) Pairing interaction: Two spins couple to S = 0 Only relevant in stable odd-mass nuclei Cross section scale set by single-proton/neutron spin expectation value A N S N N 2 = S n 2, S p u Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

35 Non-relativistic effective field theory SI and SD interactions only consider the leading-order operators (O 1, O 4 ) in the non-relativistic basis spanned by 1 χ, 1 N, S N, S χ, q, v Fitzpatrick et al. JCAP02 004(2013), Anand et al. PRC (2014) Interferences occur between some of the terms, which map into 6 different nuclear responses M (SI scattering), Σ, Σ (SD scattering),, Φ, Φ (new responses) nuclear structure calculations to interpret dark matter detection data Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

36 Chiral effective field theory Chiral EFT: low energy approach to QCD, nuclear structure energies Approximate chiral symmetry: pion exchanges, contact interactions Systematic expansion: nuclear forces and currents 2N force 3N force 4N force N e ν LO NLO N N N e ν N N e ν 2 N LO π N N N N 3 N LO Park et al. PRC (2003) Weinberg, van Kolck, Kaplan, Savage, Meißner, Epelbaum, Weise... Short-range couplings fitted to experiment once Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

37 Chiral EFT WIMP-nucleus interactions WIMP quark/gluon 1b+2b interactions at hadronic scale, map into NREFT Hoferichter, Klos, Schwenk PLB (2015) Chiral EFT hierarchy to be complemented with nuclear effects (coherence) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

38 Dark matter coupling to two nucleons Coherent contributions from 2b currents: π coupling, via scalar current and energy-momentum tensor θ µ µ Hoferichter et al. PRD (2016) 2b scalar currents also explored by Cirigliano et al. JHEP10 25(2012) PLB (2014) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

39 Generalized coherent scattering Generalized spin-independent scattering cross section: dσχn SI dq 2 = 1 c M 4πv 2 + F+ M (q2 ) + c M F M (q2 ) + c πf π(q 2 ) + 2 structure factors m χ =10 GeV 132 Xe F M + 2 F M 2 q 2 /m 2 N F M + 2 q 2 /m 2 N F M 2 F π 2 q 4 /m 4 N F M + 2 q 4 /m 4 N F M 2 q 4 /m 4 Φ N F+ 2 q 4 /m 4 Φ N F Fieguth et al. PRD (2018) q [GeV] In addition, interference terms between different contributions Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

40 Generalized coherent scattering with interferences Many different coherent contributions when including interferences Ar F M F M F M + F M 2 2 q 2 /m 2 N F M Ar Fb 2 Fπ 2 2 F M + Fb 2 F M + Fπ structure factors q 2 /m 2 N F Φ + F M + q 2 /4m 2 χ F M q 2 /m 2 N F M F M + structure factors FπFb 2 q 2 /m 2 N F M + Fb 2 F M Fb 2 F M Fπ q [GeV] Hoferichter, Klos, JM, Schwenk, in preparation q [GeV] Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

41 Discriminate dark matter-nucleus interactions Once dark matter scattering off nuclei is observed, key to unveil nature of dark matter-nucleus interaction discrimination power at 1.28 [%] F M 2 F 2 q 2 /4m 2 F M exposure [10 ton years] Future experiments can discriminate different interactions if markedly different q-dependence Isoscalar / isovector character can be discriminated in nuclei with N = Z vs N Z Fieguth et al. PRD (2018) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

42 Spin-dependent scattering: coupling to one nucleon S i (u) Xe S p (u) 1b currents S n (u) 1b currents In 129, Xe S n S p, Neutrons carry most nuclear spin S n = N i=1 σ i/2, S p = Z i=1 σ i/ S p (u) 1b currents 131 Xe S n (u) 1b currents F A (0) 2 2J + 1 (J + 1) = ap S p + a n S n 2 πj S i (u) u JM, Gazit, Schwenk, PRD (2012) Klos, JM, Gazit, Schwenk, PRD (2013) a n/p = (a 0 a 1 )/2, F n (0) 2 S n 2, F p (0) 2 S p 2 Couplings more sensitive to protons (a 0 = a 1 ) neutrons (a 0 = a 1 ) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

43 Spin-dependent scattering: coupling to two nucleons S i (u) Xe S p (u) 1b currents S n (u) 1b currents S p (u) 1b + 2b currents S n (u) 1b + 2b currents S p (u) 1b currents 131 Xe S n (u) 1b currents S p (u) 1b + 2b currents S n (u) 1b + 2b currents In 129, Xe S n S p, Neutrons carry most nuclear spin Couplings more sensitive to protons (a 0 = a 1 ) or neutrons (a 0 = a 1 ) 2b currents naturally involve both neutrons and protons: N N χ S i (u) π N N χ u JM, Gazit, Schwenk, PRD (2012) Klos, JM, Gazit, Schwenk, PRD (2013) Neutrons always contribute with 2b currents, dramatic increase in S p (u) Impact on dominant species 20% Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

44 Application to experiment 2b contributions make xenon SD results (more sensitive to neutrons) competitive for WIMP-proton cross-section LUX Coll. PRL (2017) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

45 Inelastic WIMP scattering off a nucleus? Very low-lying first-excited states 40, 80 kev in odd-mass xenon Energy (kev) Th 5/2 + 5/2 + 1/2 + 7/2 + 5/2 + 11/2-9/2-1/ Xe Exp (5/2) + 7/2 + 1/2 + (5/2) + 3/2 5/2+ + (9/2) - 11/2-1/2 + Energy (kev) Th 1/2 + 7/2-7/2 + 5/2 + 9/2-11/2-1/ Xe Exp 7/2-7/2 + (1/2,3/2) + 5/2 + 9/2-11/2-1/2 + JM, Gazit, Schwenk PRD (2012) If WIMPs have enough kinetic energy, inelastic scattering may be possible p ± = µv i (1 ± 1 2E µv 2 i ) Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

46 Inelastic WIMP scattering off xenon Inelastic structure factors compete with elastic ones around q 100 MeV in the kinematically allowed region S i (u) Xe S p (u) 1b + 2b inelastic S n (u) 1b + 2b inelastic S p (u) 1b + 2b elastic S n (u) 1b + 2b elastic Xe inelastic R (kg -1 d -1 ) Xe inelastic Total inelastic 129 Xe elastic 131 Xe elastic Total elastic Total E vis (kev) Baudis et al. PRD (2013) Integrated spectrum for xenon: inelastic scattering signal including γ-ray from decay of excited state One plateau to be detected for each nuclear excitation Signal of spin-dependent scattering Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

47 Outline 1 Lepton number violation, neutrino nature: neutrinoless ββ decay 2 Direct detection of dark matter: dark matter scattering off nuclei 3 Summary Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June 18 /

48 Summary Nuclear matrix elements and structure factors key for fully exploiting ββ decay and direct dark matter detection experiments Neutrinoless ββ decay: Improve matrix elements in larger configuration spaces with all relevant correlations Ab initio with 2b currents free from β decay quenching Double Gamow-Teller transitions correlated to 0νββ decay M 0ν NR-EDF R-EDF QRPA Jy QRPA Tu QRPA CH IBM-2 SM Mi SM St-M,Tk VMC Direct dark matter detection: Need to consider generalized WIMP-nucleon couplings discriminated by q-dependence 2b currents WIMP coupling to pion (scalar, θ coupling) 2b currents key in SD scattering structure factors mχ =10 GeV 132 Xe F M + 2 F M 2 q 2 /m 2 N F M + 2 q 2 /m 2 N F M 2 Fπ 2 q 4 /m 4 N F M + 2 q 4 /m 4 N F M 2 q 4 /m 4 Φ N F+ 2 q 4 /m 4 Φ N F q [GeV] A Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

49 Collaborators T. Otsuka T. Abe N. Shimizu Y. Tsunoda K. Yako Y. Utsuno M. Honma E. A. Coello Pérez G. Martínez-Pinedo P. Klos, A. Schwenk D. Gazit M. Hoferichter J. Engel A. Poves T. R. Rodríguez N. Hinohara E.Caurier F. Nowacki Y. Iwata Javier Menéndez (CNS, U. Tokyo) 0νββ decay and dark matter detection INT, 26 June / 44

Neutrinoless Double Beta Decay within the Interacting Shell Model

Neutrinoless Double Beta Decay within the Interacting Shell Model Institute for Nuclear Physics, Technical University Darmstadt (TUD) ExtreMe Matter Institute (EMMI), GSI EFN 2010, El Escorial, 27-29 September