1. Neutrino mass spectroscopy using atoms/molecules M. Yoshimura @Okayama Univ. yoshimura 02/05/2013 @Milano 1 Search for the missing link of micro- and macro- worlds On behalf of SPAN collaboration

2. Plan of this talk Introduction Experimental principles of neutrino mass spectroscopy using atoms/molecules Radiative emission of neutrino pair （ RENP ） vs Paired superradiance(PSR) Measurables: largest neutrino mass, IH vs NH, Majorana vs Dirac distinction, Majorana CP phases Macro-coherence development, Formation of solitons Experimental status on pH2 PSR, Xe RENP experiments yoshimura 02/05/2013 @Milano 2 vs

3. What our experiment can measure Indivisual masses; Hierarchy pattern; NH vs IH Distinction of Majorana vs Dirac mass type CPV phases; yoshimura 02/05/2013 @Milano 3 Majorana MD common ( cosmic background of 1.9 K may also be measurable )

4. Principle of the experiment yoshimura 02/05/2013 @Milano De-excitation of excited atom: Observe photon spectrum: Spectrum has information on: Absolute mass Mixing angle or phases Majorana/Dirac distinction CPV phases 4 Table top exp. Combined weak + QED

5. Theory of experimental principles and numerical results yoshimura 02/05/2013 @Milano 5

6. RENP amplitude Atomic de-excitation: process certainly existing in electroweak theory, assuming finite neutrino masses and mixing yoshimura 02/05/2013 @Milano 6 E1 x M1 transition of atomic electron weak QED

7. 6 threshold locations yoshimura 02/05/2013 @Milano 7 Macro-coherence, needed for rate enhancement, assures the momentum and the energy conservation of 3-body process, giving the threshold locations (ignoring atomic recoil) Decomposition into neutrino mass eigenstates made possible by precision of trigger laser frequency Easily accurate to mu eV, hence sensitive to meV neuMass

8. Rate estimate of RENP RENP rate For Xe – n=10 21 /cc – V=100 cc – Assumed: field energy efficiently stored in atomic system yoshimura 02/05/2013 @Milano (1)Atomic factor with macro coherence (3) Spectrum: mixing + kinematics (2) Field energy stored in atomic system (1) (2) (3) 8

9. Typical experiment would involve Measure increased CW signals, or Measure emergence of PV quantities Repeat with different to get spectrum yoshimura 02/05/2013 @Milano 9

10. RENP rate formula & spectrum yoshimura 02/05/2013 @Milano 10 Decomposed into 3 factors Dynamical factorcalculated by numerical integration of master eq. interference term due to Majorana identical pair emission Overall rate Spectral shape

11. Rate amplification by macroscopic coherence Super-radiance coherent volume – In case of SR, coherent volume is proportional to 2 L. – Phase decoherence time (T 2 ) must be longer than T SR For a process with plural outgoing particles Phase matching condition (momentum conservation) is satisfied. Coherent volume is not limited by., can be macroscopic. yoshimura 02/05/2013 @Milano 11 Details confirmed by simulation of master equation in 1+1 dim

12. Threshold weights yoshimura 02/05/2013 @Milano 12 Determined by using oscillation exp. data CPV phase dependence

13. Observables: photon energy spectrum yoshimura 02/05/2013 @Milano 13 Xe NH IH

14. Near the threshold region yoshimura 02/05/2013 @Milano Absolute masses: Thresholds for (m i,m j ) NH-IH distinction:  0 E  [eV] 14

15. Dirac vs Majorana & CP phases yoshimura 02/05/2013 @Milano E  [eV] 15  0 We need to go to the lower energy to see M-D distinction or CP phases. Eeg= 0.429 eV Epg= 0.446 eV [ref] D.N. Dinh, S. Petcov, N. Sasao, M. Tanaka, and M. Yoshimura, PLB A. Fukumi et al., PTEP (79 pages) D-NH M-IH CPV

16. How can Majorana vs Dirac distinction arise ? yoshimura 02/05/2013 @Milano Weight at thresholds M1( ) x E1( ) 16 Majorana phases Majorana field Dirac field (Majorana case) Rate proportional to

17. Easiness of measurables Largest neutrino mass from the kink of spectrum IH vs NH distinction Majorana vs Dirac distinction Majorana CP phases Last two requires < O(0.4) eV energy difference yoshimura 02/05/2013 @Milano 17

18. Twin process and its control PSR can be background ? yoshimura 02/05/2013 @Milano 18 RENP: E1 x M1 Weak PSR: E1 x M1 PSR can be dangerous, but controlable with soliton formation, giving confined field condensate that trigger RENP Can coexist for heavy atoms/molecules

19. Paired Super-Radiance (PSR) Macro-coherent amplification – A new type of coherent phenomena – Should be established experimentally Two photon emission process Paired Super-Radiance – QED instead of weak process – Good experimental signature; i.e. back-to- back radiations with same color. yoshimura 02/05/2013 @Milano 19 We need weaker PSR for macro-coherence development of RENP

20. Master equations for PSR and trigger: medium polarization coupled with two-mode fields yoshimura 02/05/2013 @Milano 20 : 2 types of relaxation Density matrix for mixed states

21. PSR dynamics clarified by simulations (MB eq.) yoshimura 02/05/2013 @Milano 21 [ref] M. Yoshimura, N. Sasao and M.Tanaka, arXiv:1203.5394v1 [quant-ph] PRA With no coherence, a large target relaxation time is required

22. Recent progress in PSR dynamics 2 yoshimura 02/05/2013 @Milano 22 Explosive events expected!. ~ 70% of stored energies are released within a few nsec. Life time shortened by 10 25 2  process natural life time :  ~ 10 16 sec. Required relaxation time O[ns]

23. How target population and polarization is developed yoshimura 02/05/2013 @Milano 23

24. Dynamical factor for RENP yoshimura 02/05/2013 @Milano 24 Without soliton formation, large PSR outputs from target ends With soliton formation, exponentially small PSR leakage Spatial profiles of solitons pH2 case Time variation

25. From trigger to PSR, soliton formation and RENP yoshimura 02/05/2013 @Milano 25 Many solitons inside, but no PSR from edges

26. Experimental status yoshimura 02/05/2013 @Milano 26

27. PSR experiment with para-H 2 Vibrational transitions of solid para-H 2 are good candidates. – Well quantized rotational and vibrational states – Dipole forbidden and two-photon allowed – Long decoherence time yoshimura 02/05/2013 @Milano homonuclear diatomic molecule 27

28. e (v= 1) (v= 0) Realistic parameters:

29. 27 Dec. 2012, X00 meeting How much coherence can be expected? v=1,J=0 v=0,J=0  532nm683nm pH 2 1 atm at 77 K (density of ~10 20 cm 3 ) 532:5 GW/cm 2 683:5 GW/cm 2 detuning  5 mJ, 8 ns, Diam ~ 200  m Numerical simulation solving Maxwell-Bloch equation F.L. Kien et al., Phys. Rev. A 60, 1562 (1999) Simulation code by Prof. Ohfuti, Prof. Katsuragawa (UEC) -4-202468 10 Raman sidebands

30. yoshimura 02/05/2013 @Milano 30

31. Nd:YAG out 355nm (150mJ/p) Dye-out(500nm)=24 mJ/p Dye BBO BBO-out (250nm) 3.5 mJ Nd: YAG (1064nm → 355nm) Xe gas inlet UV lens Vacuum gauge Fluorescence detectors Monochromator ・（ CCD/Photo-diode/PMT ） Xe gas chamber Pulsed Dye laser Pulsed YAG laser (1 – 100 Torr) Dichroic mirror Xe spectroscopy for RENP

32. 823.10 827.98 834.68 881.90 895.24 904.51 916.15 Transverse direction λ p =252.4nm 1.2 mJ input f=500mm Xe 50 Torr 1sec Longitudinal direction λ p =252.4nm 2.0 mJ input f=500mm Xe 50 Torr 1sec 840.92 Pump 823.18 895.26 calibrated Monochromator Spectrum

33. 823.27 827.99 834.67 840.87 882.01 895.05 905.18 916.74 980.30 992.46 Observed spectrum following two-photon excitation from Pump wavelength ： 252.4nm Pump power : 1.8 mJ/p Xe density: 100 Torr Focus: f500mm excitation ① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ① ② ⑤ ⑥ ⑧ ⑩ ④ ③ Monochromator Pump ⑨ ⑦

34. ND Filter slit φ1mm Band-pass Filter (820nm) Photo Diode (φ11.3mm) 225mm180 Gaussian-fitting: FWHM = 2.82 mm focus lens removed 823nm fluoreacense Xe cell Dichroic 0 80 2θ=2.82/180 =0.01567rad=0.90° 1mm 2.82 2θ 180 Angular distribution of 823nm fluorescence in laser direction

35. summary Experimental detection of RENP possible with soliton formation (development and control of two-photon mode) Perhaps 1 st discovery after RENP identification is the largest neutrino mass, NH vs IH distinction Next is MD distinction Majorana CP measurement is harder yoshimura 02/05/2013 @Milano 35

36. backup yoshimura 02/05/2013 @Milano 36

37. 37 Observability of relic neutrino hep-ph/0703019 Pauli blocking effect yoshimura 02/05/2013 @Milano

38. 38 Threshold reduction 1/2x1/2 = 1/4 Temperature measurement possible ? Case of laser irradiated pair emission For m_1 < 1meV, temperature measurement is not difficult Photon energy Relative rate yoshimura 02/05/2013 @Milano

39. Soliton formation as static remnants yoshimura 02/05/2013 @Milano 39 R-, L-moving fields, and medium polarization are confined

40. PSR dynamics (1) yoshimura 02/05/2013 @Milano 40

41. 41 Superradiance: 2 level and 1 photon case Rate enhanced by N Delayed enhanced signal accompanied by ringing yoshimura 02/05/2013 @Milano

42. Effective 2-level model for trigger and medium evolution 42 yoshimura 02/05/2013 @Milano 2 level interaction with field Ba

43. Bloch vector and Maxwell-Bloch equation yoshimura 02/05/2013 @Milano 43 Phase condition Bloch vector Bilinears in amplitudes Without relaxation

44. yoshimura 02/05/2013 @Milano 44

45. Present status of neutrino physics Oscillation experiments – Finite mass – Flavor mixing – Only mass-squared difference can be measured. yoshimura 02/05/2013 @Milano e [|U ei | 2 ]  [|U  i | 2 ]  [|U  i | 2 ] Normal (NH)Inverted (IH)  m 2 atm =(50meV) 2 sin 2  13  m 2 sol    (Mass) }    } or  m 2 sol =(10 meV) 2  m 2 atm 45

46. Prospect of Neutrino Physics Mixing （ angles  ・ phases  ） Majorana （ =, phases  ） _ Mass structure （ Absolute: difference NH/IH) Neutrino Spectroscopy with Atoms Neutrino-less Double beta-decay Neutrino Oscillation Experiments Cosmology and Particle Physics Known/unknowns In neutrino Physics Measured Present and Future Neutrino Physics （ Understandings of matter-dominated Universe, origin of Mass, GUT ） Physics beyond Standard Model yoshimura 02/05/2013 @Milano 46

47. 47 M vs D in 2-component equations yoshimura 02/05/2013 @Milano In terms of 2-spinor Lepton number manifestly violated Lepton number conserved

48. Lepto-genesis Leading theory to explain the matter-antimatter imbalance of our universe Prerequisite: lepton number violation, CP violation Enhanced expectation due to discovery of finite neutrino mass in neutrino oscillation experiments Sensitivity to low energy parameters Davidsson-Ibarra, NPB648, 345(2003) yoshimura 02/05/2013 @Milano 48

49. For RENP To RENP, minimize PSR output and maximize stored solitons Soliton results as final static remnants of master eqs. Its analytic profile (spatial) is known for special cases. It has a spinorial topological character and stable against PSR Both absorber and emitter exist Stationary solutions are aggregate of balanced absorbers and emitters without net PSR at target ends (long target required). Ideal form of target for precision neutrino mass spectroscopy yoshimura 02/05/2013 @Milano 49 Topologically stable soliton Stability guaranteed Both absorber and emitter exist