Characterization of quasi-projectiles produced in symmetric collisions studied with INDRA Comparison with models

The characterization of hot quasi-projectiles produced in symmetric or quasi-symmetric reactions (Au + Au, Xe + Sn, Ni + Ni, Ar + KCl) at di erent incident energies are estimated by means of two di erent procedures. The advantages and disadvantages of each method are analyzed on the basis of simulations using events produced by two slightly di erent models: HIPSE and ELIE.Comment: A para\^itr

Phase-space methods in nuclear reactions around the Fermi energy

Some prescriptions for in-medium complex particle production in nuclear reactions are proposed. They have been implemented in two models to simulate nucleon-nucleus (nIPSE) and nucleus-nucleus (HIPSE) reactions around the Fermi energy \cite{Lac04,Lac05}. Our work emphasizes the effect of randomness in cluster formation, the importance of the nucleonic Fermi motion as well as the role of conservation laws. The key role of the phase-space exploration before and after secondary decay is underlined. This is illustrated in the case of two debated issues: the memory loss of the entrance channel in central collisions and the $(N,Z)$ partitions after the pre-equilibrium stage.Comment: Proceedings of the IWM2005 workshop, Catane (Italy), Nov. 2005. DOWNLOAD HIPSE program at: http://caeinfo.in2p3.fr/theorie/theory_lacroix.htm

Bimodality as a signal of Liquid-Gas phase transition in nuclei?

We use the HIPSE (Heavy-Ion Phase-Space Exploration) Model to discuss the origin of the bimodality in charge asymmetry observed in nuclear reactions around the Fermi energy. We show that it may be related to the important angular momentum (spin) transferred into the quasi-projectile before secondary decay. As the spin overcomes the critical value, a sudden opening of decay channels is induced and leads to a bimodal distribution for the charge asymmetry. In the model, it is not assigned to a liquid-gas phase transition but to specific instabilities in nuclei with high spin. Therefore, we propose to use these reactions to study instabilities in rotating nuclear droplets.Comment: 4 pages, 4 figures Accepted to PR

A Case Study in Playwriting: Laura Wade's Posh

This dissertation is a case study focusing on how a play is developed during the production process. By breaking down the changes that took place in the six years (2007-2012) of edits in Laura Wade's Posh, one can see that a script is only finished once it begins production. The adjustments Wade made reflects the change in the British political, financial and sociological environment, which affects the scripts. This illustrates that theatre is an organic medium, and should evolve throughout the production process. Writing a complete script is just the beginning in theatre though there are classes, books and workshops one can take to write a play, the final product is not complete until it moves into production. Knowing Wade's projection as a playwright, how she writes, as well as her theatre history, one concludes that theatre is a group effort and that writing a play is only the first step in a complicated, multifaceted medium when working in the theatre

Measurement of collective flow in heavy ion collisions using particle pair correlations

We present a new type of flow analysis, based on a particle-pair correlation function, in which there is no need for an event-by-event determination of the reaction plane. Consequently, the need to correct for dispersion in an estimated reaction plane does not arise. Our method also offers the option to avoid any influence from particle misidentification. Using this method, streamer chamber data for collisions of Ar+KCl and Ar+BaI2 at 1.2 GeV/nucleon are compared with predictions of a nuclear transport model

Comparison of Vlasov-Uehling-Uhlenbeck model with 4 π Heavy Ion Data

Streamer chamber data for collisions of Ar + KCl and Ar + BaI2 at 1.2 GeV/nucleon are compared with microscopic model predictions based on the Vlasov-Uehling-Uhlenbeck equation, for various density-dependent nuclear equations of state. Multiplicity distributions and inclusive rapidity and transverse momentum spectra are in good agreement. Rapidity spectra show evidence of being useful in determining whether the model uses the correct cross sections for binary collisions in the nuclear medium, and whether momentum-dependent interactions are correctly incorporated. Sideward flow results do not favor the same nuclear stiffness parameter at all multiplicities

Double beta decay of 48^{48}Ca

$^{48}$Ca, the lightest double beta decay candidate, is the only one simple enough to be treated exactly in the nuclear shell model. Thus, the $\beta\beta(2\nu)$ half-life measurement, reported here, provides a unique test of the nuclear physics involved in the $\beta\beta$ matrix element calculation. Enriched $^{48}$Ca sources of two different thicknesses have been exposed in a time projection chamber, and yield T$_{1/2}^{2\nu} = (4.3^{+2.4}_{-1.1} [{\rm stat.}] \pm 1.4 [{\rm syst.}]) \times 10^{19}$ years, compatible with the shell model calculations.Comment: 4 pages, LaTex, 3 figures imbedded, PRL forma

Isospin diffusion in semi-peripheral 58Ni^{58}Ni + 197Au^{197}Au collisions at intermediate energies (I): Experimental results

Isospin diffusion in semi-peripheral collisions is probed as a function of the dissipated energy by studying two systems $^{58}Ni$ + $^{58}Ni$ and $^{58}Ni$ + $^{197}Au$, over the incident energy range 52-74\AM. A close examination of the multiplicities of light products in the forward part of phase space clearly shows an influence of the isospin of the target on the neutron richness of these products. A progressive isospin diffusion is observed when collisions become more central, in connection with the interaction time