521 research outputs found
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 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 Ca
Ca, the lightest double beta decay candidate, is the only one simple
enough to be treated exactly in the nuclear shell model. Thus, the
half-life measurement, reported here, provides a unique test
of the nuclear physics involved in the matrix element calculation.
Enriched Ca sources of two different thicknesses have been exposed in a
time projection chamber, and yield T years, compatible with the shell
model calculations.Comment: 4 pages, LaTex, 3 figures imbedded, PRL forma
Isospin diffusion in semi-peripheral + 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 + and
+ , 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
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