Large-angle {alpha}-particle scattering on {sup 12}C and search for signatures of {alpha}-particle Bose condensation

Journal Article · Mon Nov 15 00:00:00 EST 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.82.054618· OSTI ID:21499195

Belyaeva, T L ^[1]; Danilov, A N; Demyanova, A S; Ogloblin, A A ^[2]; Goncharov, S A ^[3]; Perez-Torres, R ^[4]

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1. Universidad Autonoma del Estado de Mexico, C.P. 50000, Toluca (Mexico)
2. RRC Kurchatov Institute, Moscow RU-123182 (Russian Federation)
3. Skobeltsyn Institute of Nuclear Physics, Vorob'evy Gory, Moscow (Russian Federation)
4. Universidad Tecnologico del Valle de Toluca (Mexico)

Evidence of the 3{alpha}-particle condensate character of the Hoyle state (the 0{sub 2}{sup +} state at 7.65 MeV in {sup 12}C) implies not only an enhanced radius of {sup 12}C in this state, which was established by many theoretical calculations and confirmed by the recent diffraction model analysis, but also zero relative angular momenta between clusters. We performed coupled-channels model calculations of the angular distributions of {alpha}+{sup 12}C elastic and inelastic (to the 4.44-MeV 2{sup +}, 7.65-MeV 0{sub 2}{sup +}, and 9.65-MeV 3{sub 1}{sup -} states) scattering at 110 MeV and found the ratio of the empirical spectroscopic factors S(L). As the differential cross sections of these reactions are characterized by pronounced enhancement and strong oscillations at large angles, we assumed a potential scattering in the forward hemisphere and the direct transfer of a {sup 8}Be cluster at {theta}{sub c.m.}>90 deg. and took into account the direct transfer of {sup 8}Be in the ground state and in the first excited 2{sup +} and 4{sup +} states. We found that the cluster configuration with L=0 dominates in the 0{sub 2}{sup +} state, being more than three times larger than that in the ground state. This result provides additional evidence of the condensed structure of the Hoyle state in {sup 12}C with a dominance of zero relative angular momentum. The negative-parity 3{sub 1}{sup -} excited state in {sup 12}C observed above the 3{alpha} threshold is also considered to have the 3{alpha}-cluster structure. The present calculations described well the structure of the large-angle cross section on this state. We found a positive interference for all allowed {alpha}+{sup 8}Be configurations with a dominance of the p-orbital (69%){alpha}+{sup 8}Be motion and confirmed the exotic, but hardly a condensed, structure of this state.

• OSTI ID: 21499195
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 82, Issue 5; Other Information: DOI: 10.1103/PhysRevC.82.054618; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA PARTICLES
ANGULAR DISTRIBUTION
ANGULAR MOMENTUM
BERYLLIUM 8
CARBON 12
CONDENSATES
CONFIGURATION
COUPLED CHANNEL THEORY
DIFFERENTIAL CROSS SECTIONS
DIFFRACTION MODELS
ELASTIC SCATTERING
INELASTIC SCATTERING
INTERFERENCE
MEV RANGE 01-10
OSCILLATIONS
PARITY
PARTICLES
POTENTIAL SCATTERING
SPECTROSCOPIC FACTORS
ALKALINE EARTH ISOTOPES
ALPHA DECAY RADIOISOTOPES
BERYLLIUM ISOTOPES
CARBON ISOTOPES
CHARGED PARTICLES
CROSS SECTIONS
DIMENSIONLESS NUMBERS
DISTRIBUTION
ENERGY RANGE
EVEN-EVEN NUCLEI
IONIZING RADIATIONS
ISOTOPES
LIGHT NUCLEI
MATHEMATICAL MODELS
MEV RANGE
NUCLEI
PARTICLE MODELS
PARTICLE PROPERTIES
RADIATIONS
RADIOISOTOPES
SCATTERING
STABLE ISOTOPES