Light nucleus clustering in fragmentation above 1 A GeV

1. Light nucleus clustering in fragmentation above 1 A GeV N. P. Andreevaa, D. A. Artemenkovb,V. Bradnovab, M. M. Chernyavskyc, A. Sh. Gaitinova, S. P. Kharlamovc, A. D. Kovalenkob, М. Haiducd, S. G. Gerasimovc, L. A. Goncharovac, N. Kachalovab V. G. Larionovac, F. G. Lepekhine, A. I. Malakhovb, A. A. Moiseenkof, G. I. Orlovac, N. G. Peresadkoc, N. G. Polukhinac, P. A. Rukoyatkinb, V. V. Rusakovab, V. R. Sarkisyanf, T. V. Schedrinab, B. B. Simonove, E. Stane, R. Stanoevag, I. Tsakovg, S. Vokalh, P. I. Zarubinb, andI.G Zarubinab aInsitutute of Physics and Technology, Almaty, Kazakhstan bJoint Institute for Nuclear Research, Dubna, Russia cP. N. Lebedev Physical Institute, RAS, Moscow, Russia dInstitute of Space Sciences, Bucharest-Magurele, Romania ePetersburg Institute of Nuclear Physics, RAS, Gatchina, Russia fErevan Physical Institute, Erevan, Armenia gInsttitute for Nuclear Research and Nuclear Energy, BAS, Sofia, Bulgaria hP. J. Šafárik University, Košice, SlovakRepublic

2. 14N Dissociation with 8Be like fragmentation proton 3 after

3. Mg-Si Dissociation into charge state 2+2+2+2+2+1 5 +proton

4. Dubna: Relativistic Nuclei

5. Nuclotron

6. Fragmentation of a 28Si of the energy of 3.65A GeV in on an emulsion nucleus. On the upper photograph one can see the interaction vertex and the jet of fragments in a narrow cone along four accompanying single-charged particles in a wide cone and three fragments of the target-nucleus. Moving toward the fragment jet direction (upper photograph) it is possible to distinguish 3 Z=1 fragments and 5 Z=2 fragments. An intensive track on the upper photograph (the third one from above) is identified as a very narrow pair of Z=2 fragments corresponding to the 8Be decay. A three-dimensional image of the event was reconstructed as a plane projection by means of an automated microscope (Lebedev Institute of Physics, Moscow) of the PAVIKOM complex.

7. Fission Fragments in Films Relativistic Nuclei in Emulsion P A V I C O M

8. Clustering building blocks:more than one nucleon bound, stable & no exited states below particle decay thresholds – deuteron, triton, 4He, and 3He nuclei

9. Secondary beams of light radioactive nuclei will be produced mostly via charge exchange reactions. 8B and 9Be beams has been formed via fragmentation of 10B.

10. Toward stability frontier =1.58 MeV 11N =0.23 MeV 8C =1.4 MeV 7B =0.092 MeV 6Be =1.5 MeV 5Li

11. Advantages of relativistic fragmentation • a limiting fragmentation regime is set in, • 2. the reaction takes shortest time, • 3. fragmentation collimated in a narrow cone – 3D images, • 4. ionization losses of the reaction products are minimum, • 5. detection threshold is close to zero.

13. 4.5 A GeV/c 16O

14. 4.5A GeV/c 16O

15. =0.092 MeV A=6

16. 4.5A GeV/c 6Li

17. 7Li.About 7% of all inelastic interactions of 7Li nuclei are “white” stars (80 events). Decay of 7Li nucleus to -particle and triton - 40 events.

18. Deuteron-Alpha Clustering in Light Nuclei 50V(0.25%) 14N(99.634%) 10B(19.9%) 6Li(7.5%) d

19. 1.9 A GeV 10B 10B is disintegrated to 2 doubly charged and 1singly charged particles in 70% of “white” stars. A singly charged particle is the deuteron in 40% like in case of 6Li. 8Be contribution is 20%. 10В9Bep – 3%

20. 1.3A GeV 9Be dissociation in 2+2. 10B9Be, Nuclotron, 2004. “white” star with recoil proton with heavy fragment of target nucleus

21. θ, 10-3 rad

24. M*2=(ΣPj)2=Σ(Pi ∙Pk) Q2=M*-M2  The Q2α distribution for the fragmentation channels 9Be2.

25. 2.9A GeV/c 14N Dissociation 14N nucleus, like the deuteron, 6Li and 10B, belong to a rare class of even-even stable nuclei. It is interesting to establish the presence of deuteron clustering in relativistic 14N fragmentation.

26. 2.1 A GeV 14N By systematic scanning over primary tracks, 42 «white» stars have already been found among 540 inelastic events. The secondary tracks of «white» stars are concentrated in a forward 8° cone. They are distributed over the charge modes as follows: 3He+H - 33%, C+H - 31%, B+2H - 7%, B+He - 7%, Be+He+H - 2%, Li+He+2H - 2%, Li+4H 2%.

28. M*2=(ΣPj)2=Σ(Pi ∙Pk) Q3=M*-Mc Q3α distribution for the fragmentation channels 14N3

29. Pure 3He Nucleus Clustering in Light Nuclei ? 9C 8B 7Be 6Be

30. 2 A GeV/c 7Be. Splitting to HeHe with two target fragments, HeHe, HeHH, 6Lip, and 4H.

31. Relativistic 7Be fragmentation: 2+2 The 7Вe*3He decay is occured in 22 “white stars” with 2+2 topology. In the latter, 5 “white” stars are identified as the 7Вe*(n) 3He3He decay. Thus, a 3He clustering is clearly demonstrated in dissociation of the 7Be nucleus.

32. 2 A GeV/c 10B 8B

33. 10B 9Be 12C 7Li 8B 9C 7Be 3He Emulsion stacks are exposed in «beamcocktails» of 9C&3He,9Be& 7Li, and 8B &7Benuclei produced via primary 12C and 10B fragmentation.

34. “Ternary H&He Process” 8B 0.769 s + The 10B nuclei with a momentum of 2A GeV/c and an intensity of about 108 nuclei per cycle were accelerated at the JINR nuclotron. A beam of secondary nuclei of a magnetic rigidity corresponding to Z/A = 5/8 (10В8B fragmentation) was provided for emulsions. We plan to determine the probabilities 8B7Bер (15), 3,4He3Hep (9),HeHHp (10) , 6Lipp (1),and HHHpp (3).

35. “Ternary 3He Process” 2 A GeV/c Carbon beam of a magnetic rigidity Z/A = 6/9 (12C9C) was provided for emulsions to determine the probabilities 9C 8Bp (1) ,7Bерp (2) , HeHepp (7), HeHHpp (5) , HeHeHe (3). 9C 0.1265 s 9B 540 eV + 6Be & 3He

36. “3He Process: mixed isotope fusion” 12C 98.89 % + 12N 11.0 ms 11C 20.38 m 14O 70.6 s CNO cycle 7Be 53.3 d 15O 122 s + 11B 80.2 % + 10B 19.8% 10C 19.2 s 14O 70.6 s 6Be & 4He 13O 8.58 ms

37. 3.65A GeV 20Ne Dissociation into charge state 2+2+2+2+2 with 8Be pair

38. 4.5A GeV/c 24Mg Peripheral Dissociation into charge state 2+2+2+2+2+2 with 8Be and 12C* like fragments

39. 4.5A GeV/c 28Si Dissociation into charge state 2+2+2+2+2+2+1 (narrow cone) with pair of 8Be and triple 12C* like fragments

42. The common topological feature for fragmentation of the Ne, Mg, Si, and S nuclei consists in a suppression of binary splittings to fragments with charges larger than 2. The growth of the fragmentation degree is revealed in an increase of the multiplicity of singly and doubly charged fragments up to complete dissociation with increasing of excitation. This circumstance shows in an obvious way on a domination of the multiple cluster states having high density over the binary states having lower energy thresholds.

43. 158 A GeV/c Pb

44. 158 A GeV/c Pb

45. Alpha-particle condensation in nucleiP. Schuck, H. Horiuchi, G. Ropke, A. Tohsaki, C. R. Physique 4 (2003) 537-540 At least light nα-nuclei may show around the threshold for nα disintegration, bound or resonant which are of the α-particle gas type, i. e., they can be characterized by a self-bound dilute gas of almost unperturbed α-particles, all in relative s-states with respect to their respective center of mass coordinates and thus forming a Bose condensed state. Such state is quite analogous to the recently discovered Bose condensates of bosonic atoms formed in magnetic traps. The only nucleus, which shows a well-developed α-particle structure in its ground state is 8Be. Other nα-nuclei collapse in their ground states to much denser system where the α-particles strongly overlap and probably loose almost totally their identity. When these nα-nuclei are expanded, at some low densities α-particles reappear forming a Bose condensate. If energy is just right, the decompression may stall around the α-condensate density and the whole system may decay into α-particles via the coherent state. 12C→3 α, ….,40Ca→10 α, 48Cr→3 16O, 32S→16O+4 α

49. bik=-(Pi/mi-Pk/mk)2 The bik distribution for the fragmentation channels 22Nen

50. Q’ = (M*-M’)/A The Q’ distribution for the fragmentation channels 22Nen.