187 research outputs found
Nuclear States with Abnormal Radii
The radius of a nuclear state is one of the most important its characteristics. Presently there were developed some methods exploiting special features of the nuclear reactions leading to short – lived excited states and allowing determination of their radii. Evidence of existing nuclear excited states with enhanced radii (size isomers) was obtained
Analytical approximation for the sphere-sphere Coulomb potential
A simple analytical expression, which closely approximates the Coulomb
potential between two uniformly charged spheres, is presented. This expression
can be used in the optical potential semiclassical analyses which require that
the interaction be analytic on and near the real r-axis.Comment: 4 pages including 3 figures and 1 tabl
Possible Existence of Neutron-Proton Halo in 6Li
One of the most recent results was the determination of the proton halo in the first excited state of the 13N nucleus using of an analog of the MDM method for the charge exchange reactions (3He, t). It turned out that this state has the same radius as the mirror state 1/2+, 3.09 MeV in 13C.This observation allows us to take the next step and try to apply this approach to measure the radii of states. The increased radii in the isobar - analogue states of the 6He-6Li-6Be triplet, which may also have a halo structure, are not excluded. As a first step, we analyzed the published differential cross sections for inelastic scattering of 3He + 6Li with the excitation of the 2.19 MeV, 3+ state at energies 34 and 72 MeV and 3.56 MeV, 0+ state at energies 24.6 and 27 MeV. Probably the state 0+, 3.56 MeV has the same radius as its ”Borromian” isobar analogue 6He and is neutron-proton halo. The predicted enlarged radius because of the more extended wave function p - n, apparently, does not take place. We recall that the spatial structure of the 6He nucleus was predicted to be quite complex, in which correlations of two types appeared: ”cigar” and ”dineutron”. The question arises: does the structure of the state change so much when passing from 6He to the isobar-analoguein6Li,whichrequirestheintroductionofaspecialkindof“tango-halo”
Open Problems in Particle Condensation
particle condensation is a novel state in nuclear systems. We
briefly review the present status on the study of particle
condensation and address the open problems in this research field:
particle condensation in heavier systems other than the Hoyle state, linear
chain and particle rings, Hoyle-analogue states with extra neutrons,
particle condensation related to astrophysics, etc.Comment: 12 pages. To be published in J. of Phys. G special issue on Open
Problems in Nuclear Structure (OPeNST
Refractive elastic scattering of carbon and oxygen nuclei: The mean field analysis and Airy structures
The experimental data on the OC and OC elastic
scatterings and their optical model analysis are presented. Detailed and
complete elastic angular distributions have been measured at the Strasbourg
Vivitron accelerator at several energies covering the energy range between 5
and 10 MeV per nucleon. The elastic scattering angular distributions show the
usual diffraction pattern and also, at larger angles, refractive effects in the
form of nuclear rainbow and associated Airy structures. The optical model
analysis unambiguously shows the evolution of the refractive scattering
pattern. The observed structure, namely the Airy minima, can be consistently
described by a nucleus-nucleus potential with a deep real part and a weakly
absorptive imaginary part. The difference in absorption in the two systems is
explained by an increased imaginary (mostly surface) part of the potential in
the OC system. The relation between the obtained potentials and
those reported for the symmetrical OO and CC
systems is drawn.Comment: 10 pages, 9 figures, Phys. rev. C in pres
Diversity and Abundance of Hymenopterous Parasitoids Associated with Anastrepha fraterculus (Diptera: Tephritidae) in Native and Exotic Host Plants in Misiones, Northeastern Argentina
Some Major host species used by the tephritid fruit flies Anastrepha
fraterculus (Wiede-mann) and Ceratitis capitata (Wiedemann), including
Acca sellowiana (O. Berg) Burret, Campomanesia xanthocarpa O. Berg,
Psidium guajava L., Prunus persica (L.) Batsch, Eriobotrya japonica (Thunb.) Lindl., Citrus reticulata Blanco var. Murcott, C. aurantium L., C. paradisi
Macfadyen var. Dalan Dan, and C. paradisi var. Sudashi, were sampled for fruit fly
larvae between Feb and Dec 2000 in the northernmost section of the Paranaense forest, in the Province of Misiones, NE Argentina. Both A. fraterculus and C. capitata were obtained from these host plant species, with A. fraterculus accounting for 93% of all tephritid puparia identified. Ten species of larval-pupal parasitoids were recovered from A. fraterculus; Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Utetes anastrephae (Viereck), Opius bellus (Gahan), Diachasmimorpha longicaudata (Ashmead) (Opiinae, raconidae),
Odontosema anastrephae Borgmeier, Lopheucoila anastrephae (Rohwer),
Aganaspis pelleranoi (Brèthes) (Eucoilinae, Figitidae), Asobara anastrephae
(Muessebeck) (Alyssinae, Braconidae), and Aceratoneuromyia indica
(Silvestri) (Tetrastichinae, Eulophidae). All these parasitoids, with the exception of D. longicaudata and A. indica, are native to the Neotropical region. No parasitoids were recovered from C. capitata puparia. Asobara anastrephae
and O. anastrephae are newly recorded in Argentina, whereas D. brasiliensis,
U. anastrephae, and L. anastrephae are newly reported in Misiones. The eucoiline
A. pelleranoi wasthe most abundant parasitoid species. Acca sellowiana and P.
guajava harbored the highest parasitoid abundance and diversity.Fil: Schliserman, Pablo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: Ovruski Alderete, Sergio Marcelo. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Tucumán. Planta Piloto de Procesos Industriales MicrobiolĂłgicos; ArgentinaFil: Decoll, Olga. Instituto Nacional de TecnologĂa Agropecuaria. Centro Regional Misiones; ArgentinaFil: Wharton, Robert. Texas A&M University; Estados Unido
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