Nuclear Masses and their Importance for Nuclear Structure, Astrophysics and Fundamental Physics

Transcription

1 Winter Meeting on Nuclear Physics, Bormio, Italy 2014 Nuclear Masses and their Importance for Nuclear Structure, Astrophysics and Fundamental Physics Klaus Blaum Jan 27, 2014

2 Content Basics of nuclear masses How to weigh ions Nuclear structure / 3N-forces m/m Nuclear astrophysics 5 Fundamental studies Summary and outlook

3 1 Basics of nuclear masses E = mc 2

4 Atomic and nuclear binding energy Masses determine the atomic and nuclear binding energies reflecting all forces in the atom/nucleus. = N + Z + Z binding energy M Atom = N m neutron + Z m proton + Z m electron -(B atom + B nucleus )/c 2 δm/m < δm/m =

5 2 How to weigh an atom c,1 c,1 c,2 c,2

6 Storage and cooling techniques Penning trap Storage ring z 0 r0 ESR cm m particles at nearly rest in space relativistic particles ion cooling long storage times single-ion sensitivity high accuracy

7 Storage of ions in a Penning trap Penning trap: Storage of ions by the superposition of electric and magnetic fields B Ion q/m U Charge q Mass m The free cyclotron frequency is inverse proportional to the mass of the ions! c qb / m

8 Penning-trap mass spectrometry (3) TOF measurement MCP Detector 390 (2) Energy conversion (1) Excitation of the ion motion Mean time of flight / s Centroid: f = 1 q B 2 π m Determine atomic mass from frequency ratio with a well-known reference mass. c f 63 Ga T 1/2 = 32.4 s Excitation frequency RF / Hz f rf c,ref f c = m - m m ref e - m e

9 TRIGA-SPEC: TRIGA-LASER + TRIGA-TRAP ECR ion source TRIGA Mainz G. Hampel K. Eberhardt N. Trautmann TRIGA-LASER W. Nörtershäuser Mass separator RFQ steady 100 kw, pulsed 250 MW, neutron flux 1.8x10 11 / cm 2 s Nucl. Instrum. Meth. A 594, 162 (2008) TRIGA-TRAP

10 3 Nuclear masses and 3N-forces Nuclear structure and magic quantum numbers

11 Nuclear structure studies S 2n = B nucl (Z,N) B nucl (Z,N-2) N = 126 shell closure deformation M Atom = N m neutron + Z m proton + Z m electron -(B atom + B nucleus )/c 2

12 Ca masses pin down nuclear forces Multi-reflection time-of-flight and Penning-trap mass spectrometry 51,52 Ca B 53,54 Ca N = 28 magic number Mass measurements via S 2n establish new magic number at N = 32 N = 32 magic number Correct prediction from 3N forces F. Wienholtz et al., Nature 498, 346 (2013) ISOLTRAP (CERN)

13 Direct Mapping of Nuclear Shell Effects E. Minaya Ramirez et al., Science 337, 1207 (2012) ChemistryWorld: Tweaked weighing scales help map the island of stability Whereisthepredicted island of stability? 256 Lr with the lowest yield ever measured in a Penning trap (2 ions/minute) SHIPTRAP (GSI)

14 4 Masses for nuclear astrophysics Nuclear astrophyics studies

15 Making gold in nature Nucleosynthesis processes

16 Mass spectrometry on radionuclides

17 Nuclides at the rp-process path p process CSRe (IMP, Lanzhou) C. Weber et al., Phys. Rev. C 78, (2008) V.-V. Elomaa et al., Phys. Rev. Lett. 102, (2011) E. Haettner et al., Phys. Rev. Lett. 106, (2011) F. Herfurth et al., Eur. Phys. J. A, 47,75 (2011) X. Tu et al., Phys. Rev. Lett. 106, (2011)

18 Nuclear astrophysics: The mass of 82Zn Composition of the outer crust of a neutron star m/m ~ 10-8 (< 1 kev) ISOLTRAP (CERN) R. Wolf et al., Phys. Rev. Lett., 110, (2013)

19 5 Fundamental studies Test of the unitarity of the quark-mixing matrix Weak Interaction Radioactive decay Strong Interaction Binding between quarks within hadrons 1 0 n 1 1 p e e

20 Q EC values of superallowed beta emitters Courtesy of T. Eronen Superallowed beta emitters? Decays of nuclear states, T=1 Pure Fermi decays Simple decay matrix element Characterized with an ft value f stat. rate function;(f Q EC5 ) t partial half life t 1/2 /b Q-values needed at 100-eV level

21 Testing the Standard Model

22 Superallowed beta-emitters Q EC JYFLTRAP (IGISOL) ISOLTRAP (ISOLDE) CPT (Argonne) LEBIT (MSU) TITAN (TRIUMF)

23 The Ft picture Ft = (79) s Towner&Hardy, Rep. Prog. Phys. 73 (2010)

24 Test of the CKM unitarity Check unitarity via first row elements: V ud 2 + V us 2 + V ub = 1 + Δ V us and V ub from particle physics data (K and B meson decays) 2 Unitarity contribution: V ub V us 0.001% 5% Present status: V ud (nuclear -decay) = (22) V us (kaon-decay) = (94) V ub (B meson decay) = (5) V ud 95% V ud 2 V us 2 V ub (6) 0,9999 Towner&Hardy, Rep. Prog. Phys. 73 (2010)

25 Most recent breakthrough and future Destructive time-of-flight detection Space resolving detection Delay-line detector

26 Phase-imaging magnetron measurement Typical freq. q = e m = 100 u B = 6 T - f 1kHz + f 1MHz Mass accuracy of 4 T 1/2 < 0.1s Gain of a factor of 5 in uncertainty a factor of 40 in resolution or a factor of 25 in time. S. Eliseev et al., Phys. Rev. Lett. 110, (2013)

27 6 Future trap/ring/laser facilities at FAIR More to come with NUSTAR Nuclear Structure & Astrophysics with rare isotope beams, x10000 Dedicated storage rings HITRAP Penning traps LaSpec Laser spect. MATS Penning traps

28 Summary Precision masses provide detailed information and insights into nuclear structure properties! Tools: Penning traps and storage rings Observables: masses, binding energy, (half-lives) Nuclear structure / astrophysics / fund. studies: - Halos and separation energies - Magic numbers and shell evolution - Nucleosynthesis studies - Test of CVC and CKM unitarity - Nuclear masses for neutrino physics

29 Thanks Thanks a lot for the invitation and your attention! klaus.blaum@mpi-hd.mpg.de WWW: Max Planck Society Helmholtz Alliance (HA216) Adv. Grant MEFUCO (#290870) Helmholtz Association (VH VI 417) Member of EuroGENESIS / MASCHE.