1. The Neutron Beta-Decay Exploring the properties of fundamental interactions Hartmut Abele Bar Harbor A,B,C,D,…  The Neutron Alphabet

2. Hartmut Abele, Technische Universität München 2 1. Standard Model and Neutron Decay Neutron  -decay lifetime  ~ 15 min  -endpoint: E max = 782 keV V-A Theory: Vector coupling:g V = G F V ud f 1 (q 2 →0) Axial vector coupling: g A = G F V ud g 1 (q 2 →0) ratio = g A / g V = -1.276 Standard Model: V ud,

3. The Neutron Alphabet, Observables Electron Proton Neutrino Neutron Spin A B C A: P-odd Dr. Mund (2007) B: P-odd Schumann et al., PRL 99, 191803 (2007) C: P-odd Schumann et al., PRL 100, 151801 (2008) a Stratowa et al. (1975) D: T-oddTRINE, emiT G A. Kozela et al., PRL 102, 172301 (2009) N A. Kozela et al., PRL 102, 172301 (2009) R: T-odd A. Kozela et al., PRL 102, 172301 (2009)  a D R N see review: The neutron. Its properties and basic interactions, Prog. Part. Nucl. Phys. 60 (2008) 1-81

4. Hartmut Abele, Vienna University of Technology 4 Neutrons alphabetize the Standard Model a or A  = g A / g V

5. aSPECT, correlation a, University Mz/TUM/ILL Proton spectroscopy

6. Hartmut Abele, Atominstitut, Vienna University of Technology 6 Analyzing Plane Electrode Proton detector Neutron decay Protons Magnetic field Present best experiments: Δa/a = 5% Present status of aSPECT:( Δa/a ) stat = 2% per day Setup at the ILL-Grenoble, 2008 Anti-magnetic screen … for a = - 0.103 (PDG 2008) B0B0 UBAUBA n νeνeνeνe p+p+ e-e- θ Sensitivity of the proton spectrum to the neutrino electron correlation coefficient a UMZ, TUM, ILL: Neutron decay spectrometer aSPECT

7. aCORN Tulane (F. Wietfeldt), Indiana, NIST, et al. p e p p v v p n e-e- Fast group Slow group

8. 8 Principle: momentum space diagram Typical momentum vector for p e p  lie in a second cylinder, kinematically distinct groups a will cause an asymmetry between coincidence events between I and II. Groups I and II can be experimentally distinguished by TOF. B

9. Hartmut Abele, Atominstitut, Vienna University of Technology Hartmut Abele, University of Heidelberg 9 N ab Electron and neutrino momenta from electron energy cos  e  from proton momentum and electron energy using 4T  1T TOF between electron and proton Bowman, Pocanic et al.

10. Hartmut Abele, Technische Universität München 10 Characteristics of Experiments Using Magnetic Fields (Dubbers 1980s) A, B, C PERKEO I

11. Results A: 2004 - 2006 PERKEO II Collaboration New beam position PF1B@ILL New polarizer system 99.7% New analyzer system 100% Electron Neutron Spin A Hartmut Abele, Vienna University of Technology

12. 12 2002: result: A = -0.1189(8) = -1.2739(19) 2006: result: A = -0.1198(5) = -1.2762(13)

13. 13 PERKEO III: Impressions from the Installation at ILL Plastic Scintillator Detector Spectrometer PERKEO III B. Maerkisch, PERKEO III : Neutron Decay Measurements LiF Chopper

14. Time of Flight Spectrum 14 neutron time of flight [  s] boron beam dump homogeneous magnetic field region chopper open background measurement counts in detectors B. Maerkisch, PERKEO III : Neutron Decay Measurements

15. June 2009: Fermi Spectrum 15 Spectrum after background subtraction, downstream detector: it works! preliminary Spectra for both spin states B. Maerkisch, PERKEO III : Neutron Decay Measurements

16. June 2009: Beta Asymmetry Spectrum 16 preliminary 18h of data, downstream detector: Statistical precision ~1% / day B. Maerkisch, PERKEO III : Neutron Decay Measurements

17. Hartmut Abele, Technische Universität München 17 -1.1900(200), PDG (1960) -1.2500(200), PDG (1975) -1.2610(40), PDG (1990) -1.2594(38), Gatchina (1997) -1.2660(40), M, ILL (1997) -1.2740(30), HD, ILL (1997) -1.2686(47), Gatchina, ILL (2001) -1.2739(19), HD, ILL (2002) -1.2762(13), HD, ILL (2006) a bit history:  from neutron  -decay

18. Hartmut Abele, Technische Universität München 18

19. UCN source Polarizer / Spin flipper Diamond-coated quartz tube MWPC Plastic scintillator Light guide Superconducting solenoidal magnet (1.0 T) Decay volume Field Expansion Region Detector housing PMT Neutron absorber UCNA (ultracold neutrons) Short test run: A 0 =-0.1138(46)(21) A. Young (NCSU), A. Saunders (LANL), et al. Be coated mylar foil

20. 20 Why ratio = g A / g V from Neutrons? Processes with the same Feynman-Diagram Courtesy of D. Dubbers Hartmut Abele, Vienna University of Technology

21. Hartmut Abele, Technische Universität München 21 a,A  = g A / g V A +  V ud from CKM matrix Letters and SM spelling Quark mixing is rotation in flavor space CKM-Matrix is unitary

22. Hartmut Abele, Technische Universität München 22 Situation 1995 - 2004 Baseline from V us

23. Hartmut Abele, Atominstitut, Vienna University of Technology Present status lifetime 2 types of experiments: Beam experiments Storage experiments Storage losses 23

24. Hartmut Abele, Atominstitut, Vienna University of Technology New experiments World average 885.2 ± 0.8 s without 878.5 ± 0.8 s  = 878.2 ±1.9 Ezhov, UCN09 St. Petersburg New plans: -PENELOPE -UCN in permanet magnets -UCN in He -cold neutrons in beam 24

25. 25 a,A  = g A / g V A +   V ud from CKM matrix A + B +   Right Handed Currents (RHC)? Letters and SM spelling WLWL WRWR

26. 26 Origin of nature’s lefthandedness Standard Model: Elektroweak interaction 100% lefthanded Grand unified theories: Universe was left-right symmetric at the beginning Parity violation = 'emergent' Order parameter <100% Neutron decay: Correlation B + A:  Mass right handed W-Boson: m R > 280 GeV/c 2  Phase: -0.20 < zeta <0.07 WLWL WRWR

27. Our Result: New mean Value: B mean = 0.9807(30) Result PERKEOII: Asymmetry B & Asymmetry C Thesis: M. Schumann 2007 Background B  n Displacement B = 0.9802(50)  result is virtually independent from detector calibration result limited by statistics and error (  magnetic mirror effect) Schumann et al., Phys. Rev. Lett. 99, 191803 (2007), arXiv:0706.3788. C = -0.2377(26) Schumann et al., Phys. Rev. Lett. 100, 151801 (2008), arXiv:0706.3788.

28. 28 C = x c A + B A + B + C  Scalar Interactions  Tensor Interactions A + B + C  Right Handed Currents (RHC)? Letters and SM spelling S, T WLWL WRWR V-A

29. A + B + C +  Neutrons 29 A + B + C  Scalar Interactions  Tensor Interactions Letters and SM spelling S, TV-A World average 2007 g T /g A Schumann et al., PRL 100, 151801 (2008)

30. 30 D, R ? T-odd  CP-violation Letters and SM spelling: Times Reversal Tests CP See P. Herczeg, Prog. Part. Nucl. Phys. 46 (2001) 413.  Candidate models for scalar couplings (at tree-level):  Charged Higgs exchange  Slepton exchange (R-parity violating super symmetric models)  Vector and scalar leptoquark exchange  The only candidate model for tree-level tensor contribution (in renormalizable gauge theories) is:  Scalar leptoquark exchange Courtesy of K. Bodek

31. K. Bodek, PSI Users' Meeting No. 40, 2009 31 MWPC scintillator Pb-foil Mott polarimeter  0.2 Analyzing power Measure polarization of e in polarized n-decayMeasure polarization of e in polarized n-decay –Analyzer: Mott scattering of e on lead –Measure e-track twice –Precision: 2  10 -2 –R = 0.008 ± 0.015 ± 0.005 –For details : Bodek et al. PRL 102 172301 (2009)

32. 19-Feb-2009 Bodek, PSI Users' Meeting No. 40, 2009 32 Limits on S and T coupling constants

33. Low energy studies in the LHC era Low energy = High precision 33

34. Hartmut Abele, Atominstitut, Vienna University of Technology Super symmetry effects: B-coefficientEffect large: g-2 neutron-beta-decy 10 -5 See Ramsey-Musolf, Physics Reports 456 (2008) 1–88 Low-energy precision tests of supersymmetry

35. Hartmut Abele, Atominstitut, Vienna University of Technology Can we get there? New experiments New source for beta-decay products: PERC 35

36. Hartmut Abele, Technische Universität München 36 Cold Neutrons @ PF1B (ILL), MEPHISTO (FRM2) High Flux:  = 2 x 10 10 cm -2 s -1  Decay rate of 1 MHz / metre Polarizer: 99.7 ± 0.1 % Spin Flipper: 100.05 ± 0.1 % Analyzer: 100 % 3 He-cells Spectrometer

37. Hartmut Abele, Atominstitut, Vienna University of Technology Hartmut Abele, Technische Universität München 37

38. Summary a, A, B, C, D… In standard model: a and A are related to Sensitivity to S, V, A, T, P interaction Sensitivity to symmetries -P-violating: A, B, C, R -T-violating: D, R If T-invariance holds, coupling constants are real