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, . Haiducd, S. G. Gerasimovc, L. A. Goncharovac, N. KachalovabV. 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, KazakhstanbJoint Institute for Nuclear Research, Dubna, RussiacP. N. Lebedev Physical Institute, RAS, Moscow, RussiadInstitute of Space Sciences, Bucharest-Magurele, RomaniaePetersburg Institute of Nuclear Physics, RAS, Gatchina, RussiafErevan Physical Institute, Erevan, ArmeniagInsttitute for Nuclear Research and Nuclear Energy, BAS, Sofia, BulgariahP. J. afrik University, Koice, Slovak Republic

14N Dissociation with 8Be like fragmentation3 afterproton

Mg-Si Dissociation into charge state 2+2+2+2+2+15 +proton

Dubna: Relativistic Nuclei

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.

P A V I C O MRelativistic Nuclei in EmulsionFission Fragments in Films

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

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.

Clustering in Light Nuclei

t

3He

6Li

7Li

6He

7Be

8B

12C

10B

12N

_1066906144.doc

10B

11B

11C

9Be

10C

=1.5 MeV=0.092 MeV=0.23 MeV=1.4 MeV=1.58 MeV5Li6Be7B8C11NToward stability frontier

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.Advantages of relativistic fragmentation

4.5 A GeV/c 16O

4.5A GeV/c 16O

A=6=0.092 MeV

4.5A GeV/c 6Li

6Li

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.

Deuteron-Alpha Clustering in Light Nuclei10B(19.9%)6Li(7.5%)14N(99.634%)50V(0.25%)d

1.9 A GeV 10B10B 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%. 109Bep 3%

1.3A GeV 9Be dissociation in 2+2.10B9Be, Nuclotron, 2004.white starwith recoil protonwith heavy fragment of target nucleus

, 10-3 rad

The Q2 distribution for the fragmentation channels 9Be2. M*2=(Pj)2=(Pi Pk) Q2 =M*-M2

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.

2.1 A GeV 14NBy 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%.

Q3 distribution for the fragmentation channels 14N3M*2=(Pj)2=(Pi Pk) Q3 =M*-Mc

6Be 7Be 8B9CPure 3He Nucleus Clustering in Light Nuclei ?

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

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

2 A GeV/c 10B 8B

Emulsion stacks are exposed in beam cocktails of 9C&3He, 9Be & 7Li, and 8B & 7Be nuclei produced via primary 12C and 10B fragmentation. 10B 12C8B7Be9Be9C3He7Li

Ternary H&He Process+8B 0.769 sThe 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 (108B fragmentation) was provided for emulsions. We plan to determine the probabilities 8B7B (15), 3,4He3Hep (9), HeHHp (10) , 6Lipp (1), and HHHpp (3).

Ternary 3He Process+ 9C 0.1265 s9B 540 eV6Be & 3He 2 A GeV/c Carbon beam of a magnetic rigidity Z/A = 6/9 (12C9C) was provided for emulsions to determine the probabilities 9C 8Bp (1) , 7Bp (2) , HeHepp (7), HeHHpp (5) , HeHeHe (3).

3He Process: mixed isotope fusion+ 11C 20.38 m

13O 8.58 ms6Be & 4He12N 11.0 ms+14O 70.6 s15O 122 s+11B 80.2 %CNO cycle12C 98.89 %7Be 53.3 d10C 19.2 s10B 19.8%14O 70.6 s

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

4.5A GeV/c 24Mg Peripheral Dissociation into charge state2+2+2+2+2+2 with 8Be and 12C* like fragments

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

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.

158 A GeV/c Pb

158 A GeV/c Pb

Alpha-particle condensation in nuclei P. Schuck, H. Horiuchi, G. Ropke, A. Tohsaki, C. R. Physique 4 (2003) 537-540

At least light n-nuclei may show around the threshold for n disintegration, bound or resonant which are of the -particle gas type, i. e., they can be characterized by a self-bound dilute gas of almost unperturbed -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 -particle structure in its ground state is 8Be. Other n-nuclei collapse in their ground states to much denser system where the -particles strongly overlap and probably loose almost totally their identity. When these n-nuclei are expanded, at some low densities -particles reappear forming a Bose condensate. If energy is just right, the decompression may stall around the -condensate density and the whole system may decay into -particles via the coherent state.12C3 , .,40Ca10 , 48Cr3 16O, 32S16O+4

The bik distribution for the fragmentation channels 22Nenbik=-(Pi/mi-Pk/mk)2

The Q distribution for the fragmentation channels 22Nen. Q = (M*-M)/A

dN/dTn

Tn=(M*n - n M )/(4 n ), MeV 0

0.81.62.44.5A GeV/c12C:=0.4 MeV 22Ne5 24Mg5 +3He

Boltzmann constant, k /approx 10-4 eV K-1Typical Temperature Range, /approx 5108-9 K per

p=(2m T) p /approx 20-120 MeV

Planck constant, /approx 200 MeV fm

=/p de Broglie wave lengths /approx 1-10 fm

coh /approx R cohHe /approx RHe

T/THe= / He= (RHe/R)2 /approx 1010

Macroscopic quantum coherence phenomena in atomic physics /approx 1 K

Macroscopic quantum coherence phenomena in nuclear physics /approx 1010 K

11N 1.58 MeV12O 0.4 MeV15F 1 MeV13N 10 min20Na 448 ms 20Mg 95 msWalking along proton stability line12N 11 ms16Ne 0.122 MeV14N 99.6%13O 8.58 ms14O 70.6 s15O 122 s16O 99.8%19F 100%20Ne 90.48%16F 0.04 MeV17F 64.5 s18F 110 min17Ne 109 s18Ne 1.67 s19Ne 17.2 s

12O 0.4 MeV9C, 126.5 ms6Be, 0.092 MeV+12 MeV+16 MeV+38 MeVMultifragmentation in H&He

10C 19.2 s13O 8.58 ms16Ne 0.122 MeVMultifragmentation in H&He

11C 20.38 m14O 70.6 s17Ne 109 s20Mg 95 msMultifragmentation in H&He

Fragmentation of relativistic nuclei provides an excellent quantum laboratory to explore the transition of nuclei from the ground state to a gas-like phase composed of nucleons and few-nucleon clusters having no excited states, i. e. d, t, 3He, and .

The research challenge is to find indications for the formation of quasi-stable systems significantly exceeding the sizes of the fragments. Search for such states is of interest since they can play a role of intermediate states for a stellar nuclear fusion due to dramatically reduced Coulomb repulsion. The fragmentation features might assist one to disclose the scenarios of few-body fusions as processes inverse to fragmentation.

10B