Event generator to construct cross sections for the multiphonon excitation of a set of collective vibrational modes

The construction of differential cross sections as a function of excitation energy for systems with a collection of low- and high-lying intrinsic vibrational modes has been attempted in the past. A prescription is proposed that simplifies the implementation of such calculation schemes with a remarkable reduction in computational time.Comment: 6 pages, 3 figures, to be published in Phys. Rev.

Transfer reactions in the sudden limit of the pairing-rotor model

The transfer of multiple pairs of particles in heavy-ion reactions is studied in the sudden limit of the macroscopic pairing-rotor model

Study of Giant Pairing Vibrations with neutron-rich nuclei

We investigate the possible signature of the presence of giant pairing states at excitation energy of about 10 MeV via two-particle transfer reactions induced by neutron-rich weakly-bound projectiles. Performing particle-particle RPA calculations on $^{208}$Pb and BCS+RPA calculations on $^{116}$Sn, we obtain the pairing strength distribution for two particles addition and removal modes. Estimates of two-particle transfer cross sections can be obtained in the framework of the 'macroscopic model'. The weak-binding nature of the projectile kinematically favours transitions to high-lying states. In the case of (~^6He, \~^4He) reaction we predict a population of the Giant Pairing Vibration with cross sections of the order of a millibarn, dominating over the mismatched transition to the ground state.Comment: Talk presented in occasion of the VII School-Semina r on Heavy Ion Physics hosted by the Flerov Laboratory (FLNR/JINR) Dubna, Russia from May 27 to June 2, 200

Investigating the nucleus-nucleus potential at very short distances

Recent progress in experimental techniques have made possible accurate measurements of fusion cross sections far below the Coulomb barrier, revealing an unexpected behavior of these quantities as a function of the bombarding energy. Besides providing a plausible cause for the observed energy dependence we profit from the nature of this explanation and the high sensitivity of the experimental data to show how one can use these measurements to investigate the radial dependence of the nuclear ion-ion potential at extremely close distances

Regular and chaotic regimes in coupled-channel calculations of nuclear scattering processes

The presence of regular and chaotic regimes in nuclear scattering processes has so far been established in the context of simple, schematic reaction models. It has been argued that traces of the underlying classical organization of phase space should also be present in complex quantal calculations performed with state-of-the-art coupled-channel codes. In this paper we show that this is indeed the case and develop concrete guidelines to infer - relying exclusively on features of the quantal results - the regular or chaotic character of the motion

On nucleon exchange mechanism in heavy-ion collisions at near-barrier energies

Nucleon drift and diffusion mechanisms in central collisions of asymmetric heavy-ions at near-barrier energies are investigated in the framework of a stochastic mean-field approach. Expressions for diffusion and drift coefficients for nucleon transfer deduced from the stochastic mean-field approach in the semiclassical approximation have similar forms familiar from the phenomenological nucleon exchange model. The variance of fragment mass distribution agrees with the empirical formula $\sigma^2_{AA}(t)= N_{\rm exc}(t)$. The comparison with the time-dependent Hartree-Fock calculations shows that, below barrier energies, the drift coefficient in the semiclassical approximation underestimates the mean number of nucleon transfer obtained in the quantal framework. Motion of the window in the dinuclear system has a significant effect on the nucleon transfer in asymmetric collisions.Comment: 10 pages, 10 figures, submitted for publicatio

Cliente muerto no paga

Desde el punto de vista económico, el confinamiento es, sin dudas, la clave que impide a la economía funcionar normalmente. Lo que no pudo la amenaza nuclear, aquello en lo que fracasaron sistemas totalitarios del control social ultraplanificado, la opresión política, racial y religiosa, lo ha conseguido la interrupción del comercio. Comercio y cooperación, como se verá, han sido vitales en la recuperación de la paz. En días como estos, deudores y acreedores son la misma cosa, y la interrupción del flujo económico implica que nadie puede pagar porque nadie puede trabajar y porque a su vez nadie puede cobrar. Mantener la economía pequeña de los pequeños emprendimientos, de la vida familiar, del pequeño comercio, es darle la primera base de sustentación a todo el sistema. Como solían enseñar Schuman y Monet, padres de la idea a la Gran Europa, el mejor preventivo de la guerra es evitar la escasez. Donde ha escasez hay que buscar poner abundancia, no a través del conflicto, sino de la cooperación, aún cuando haya que sacrificar algo en pos del todo.From an economic point of view, confinement is undoubtedly the key that prevents the economy from functioning normally. What the nuclear threat failed, what totalitarian systems of ultraplanned social control failed, political, racial and religious oppression, has been achieved by the interruption of trade. Trade and cooperation, as will be seen, have been vital in the recovery of peace. On days like these, debtors and creditors are the same thing, and the interruption of the economic flow implies that nobody can pay because nobody can work and because in turn nobody can collect. Keeping the economy small for small businesses, family life, small businesses, is to give the first base of support to the entire system. As Schuman and Monet, fathers of the idea, used to teach Greater Europe, the best preventative of war is to avoid scarcity. Where there is scarcity, one must seek to put abundance, not through conflict, but through cooperation, even when something has to be sacrificed in pursuit of the whole.publishedVersionFil: Dasso, Ariel G. Universidad Nacional de Córdoba. Facultad de Derecho; Argentina

Impacto de la unificación del código civil y comercial en la ley de concursos. El vencimiento de las obligaciones a plazo frente a la quiebra y el concurso

7. Los acuerdos privados ante la crisis. Alcances. Límites

Simple estimates of excitation energy sharing between heavy and light fragments in heavy-ion reactions

Qualitative arguments are used to estiamte the ratio of excitation energies between heavy and light fragments for asymmetric heavy-ion collisions. The value of this quantity is linked to the relative role played by inelastic and transfer degrees of freedom and thereby to an approximate function of the total kinetic energy loss. A numerical analysis that confirms the trends anticipated by the simple arguments is performed for the reactions 56Fe+ 238U and 86Kr+ 208Pb at bombarding energies in the laboratory of 476 and 1565 MeV, respectivelyComisión Asesora de Investigación Científica y Técnica 2868-8