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Nuclear matrix elements. measured quantity. quantity of interest. 1 / T 1/2 = PS * NME 2 * (m / m e ) 2. The big unknown. Started worldwide effort for a coherent program to reduce NME uncertainty down to 30%, summary report available nucl-ex/0511009.
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Nuclear matrix elements measured quantity quantity of interest 1 / T1/2 = PS * NME2 * (m / me)2 The big unknown Started worldwide effort for a coherentprogram to reduce NME uncertainty down to 30%, summary report available nucl-ex/0511009 Needs international coherent effort http://www.ippp.dur.ac.uk/0NU2B/2005.html
Nuclear matrix elements 1 / T1/2= PS * ME2 * (m / me)2 charge exchange(n,p), (d,2He) charge exchange(p,n), (3He,t) muon capture nu N scattering 1+ beta- decays (A,Z+1) EC/beta+ decays antineutrino-capture 0+ (A,Z) Q - values 0+ (A,Z+2) Theory: Shopping list what to measure to improve calculations Experiment: Where can it be measured, who? „Ultimate dream“: coherent effort, strategy paper to get things done
Ca 48 4271 0.187 4.10E24 2.52E16 Ge 76 2039 7.8 4.09E25 7.66E18 Se 82 2995 9.2 9.27E24 2.30E17 Zr 96 3350 2.8 4.46E24 5.19E16 Mo 100 3034 9.6 5.70E24 1.06E17 Pd 110 2013 11.8 1.86E25 2.51E18 Cd 116 2802 7.5 5.28E24 1.25E17 Sn 124 2288 5.64 9.48E24 5.93E17 Te 130 2529 34.5 5.89E24 2.08E17 Xe 136 2479 8.9 5.52E24 2.07E17 Nd 150 3367 5.6 1.25E24 8.41E15 Phase space 0nbb decay rate scales with Q5 2nbb decay rate scales with Q11 Q-value (keV) (PS 0v)–1 (yrs eV2) (PS 2v) –1 (yrs) Isotope Nat. abund. (%)
Matrix elements 2 matrix elements determined by intermediate 1+ states 0 matrix elements different
Outcome: Working packages • Working package 1: Charge exchange reactions • Working package 2: Q-value measurements • Working package 3: Muon capture • Working package 4: Double elecron capture • Working package 5: Neutrino nucleus scattering • Working package 6: Nucleon exchange reaction Urgency: Some facilities might vanish in the near future!!!
WP1: Charge exchange Currently: (d,2He) and (3He,t) Further: ft-values of EC fixing g_pp EM transitions to IAS nuclear deformation s.r.c.
WP2: Q-values Only 76Ge known very accurate Atomic traps • Reasons: • Good energy resolution detectors- Presence of nearby background lines • - Enhancement in EC/EC modes if levels are degenerate
NNR05-Workshop Neutrino nuclear responses in particle and astro nuclear physics • -- Double beta decays and low-energy astro neutrinos----- • Dec. 1-4, CASTHarima, Osaka Japan • Neutrinos involved in bb and astro nuclear physics are mostly low-energy(0.01-0.1 GeV) neutrinos, and accordingly the responses are spin isospin responses with low multi-polarities of L= 0~3. • In fact the spin isospin responses for the lowest multi-pole of L=0 • have extensively been studied at RCNP, MSU, KVI, TUDA and others. High E-resolution systems there are very powerful. http://www.spring8.or.jp/e/conference/appeal/nnr05/