1. Search for a light neutral boson in nuclear transitions
Attila Krasznahorkay, F.W.N. de Boer, M. Csatlós, L. Csige, Z. Gácsi, J. Gulyás, M. Hunyadi, T.J. Ketel,
A. Krasznahorkay Jr., R.G. Lovas, B.M. Nyakó,
L. Stuhl, T. Tornyi, J. Van Klinken

2. Review of Particle Physics, Phys. Lett. B592 (2004)
F.W.N. de Boer, R. van Dantzig, Phys. Rev. Lett. 61 (1988) 1274 F.W.N. de Boer et al., J. Phys. G 27 (2001) L29 Report in Science
Review of Particle Physics, Phys. Lett. B592 (2004)
Gauge & Higgs Boson Particle Listings
Axion and Other Light Boson Searches in Nuclear Transitions

3. INTEGRAL satellite

5. Creation and decay of a bosonJi e– Ji

6. Search for a Massive Shortlived Axion in Nuclear Transitions Athans Hatzikoutelis (Advisor: Peter Paul, RHIC Nov. 15, 2003)
The Axion is the Goldstone boson that corrects the Strong CP Problem in the Standard Model.
The search for axions is continuing for 20 years.
If axion exists it can be produced in nuclear transitions of magnetic dipole character from excited states to the ground state of the 12C and 8Be nuclei.
12C
8Be e+ e-
Axion b- g
15.1 MeV
17.6 MeV
Made by Aqans
The Giant Dipole Resonance group is searching for the axions through their decay into electron-positron pairs.
A semispherical array of 65 scintillator detectors in coincidence with 4 neutron detectors can resolve pairs.

7. e+e- pairs from a magnetic monopole 0-  0+ transition

8. Investigate the 00+ transition in 16O!
Axion: L=0,
U-boson: L=1 decay

9. We have used the 14N(3He,p)16O reaction
Large cross-section for the 0 state.
E= 2.4 MeV 3He is sufficient.
Large Q value (15 MeV)
Absorbent foil + proton-detector
→clean!
target: TaN 4 mg/cm2 on 5 μm Ta
Beam: 0.5 μA (limited by the target)

10. The γ-e+-e -p coincidence setup

11. e+e- angular correlation for the 10.95 MeV transition

12. Building a new electron-positron spectrometer

14. Participants (and Walter Henning) of the experiment

15. Block diagram of the electronics

16. A new spectrometer was constructed
Dark2012, Frascati

17. γ and e+e- sum energy spectra measured with the improved setup
Dark2012, Frascati

18. The obtained flat angular correlation

19. γ-spectrum from the decay of the Ex=11 MeV region

20. e+e- or γγ energy correlations?

21. Reinvestigation of the 17.6 MeV M1 transition in 8Be
Dark2012, Frascati

22. Energy levels and transitions in 8Be

23. High energy γ-spectrum measured with the Clover detector

24. e+e- sum energy spectrum
Dark2012, Frascati

25. The first positive results

26. The efficiency calibration is crucial
Dark2012, Frascati

27. Some real deviation from the IPC theoretical predictions

28. Mixing up direct E1 capture events
Dark2012, Frascati

29. Let us concentrate on the isoscalar 1.04 MeV M1 transition in 8Be
Dark2012, Frascati

30. The boson showed up with an energy of 13.5±0.25 MeV (≈3σ confidence)
Dark2012, Frascati

31. A Compact Positron Electron spectrometer (COPE) for internal pair creation studies (ENSAR support)B
Beam
COPE 100:1
ATLAS
GEM detectors,
µ-TPC technology
for particle tracking,
DSP cards for readout.

32. On the construction of the spectrometer
Dark2012, Frascati

33. Thank you very much for your attention