C. P. Montoya

Statistical Multifragmentation in Central Au+Au Collisions at 35 MeV/u

Abstract Multifragment disintegrations, measured for central Au + Au collisions at E A = 35 MeV , are analyzed with the Statistical Multifragmentation Model. Charge distributions, mean fragment energies, and two-fragment correlation functions are well reproduced by the statistical breakup of a large, diluted and thermalized system slightly above the multifragmentation threshold.

Thermal source parameters in Au+Au central collisions at 35 A MeV

Central Au+Au collisions at 35 A MeV are analyzed to find the characteristics of a thermal source, in the framework of the statistical multifragmentation model SMM. A recently introduced backtracing protocol provides an effective comparison of theory and experiment. For the first time the distributions of the central source parameters (density, mass number, excitation energy) are found. The collective energy of primary fragments is also deduced. It is shown that the backtracing procedure allows an estimation of the pre-equilibrium emission. c 1998 Published by Elsevier Science B.V.

Multifragment production in Au+Au at 35 MeV/u

Abstract Multifragment disintegration has been measured with a high efficiency detection system for the reaction Au + Au at E / A = 35 MeV. From the event shape analysis and the comparison with the predictions of a many-body trajectories calculation the data, for central collisions, are compatible with a fast emission from a unique fragment source.

Circumstantial evidence for critical behavior in peripheral Au+Au collisions at 35 MeV/nucleon.

The fragmentation resulting from peripheral Au + Au collisions at an incident energy of {ital E}=35 MeV/nucleon is investigated. A power-law charge distribution, {ital A}{sup {minus}{tau}} with {tau}{approx_equal}2.2, and an intermittency signal are observed for events selected in the region of the Campi scatter plot where {open_quote}{open_quote}critical{close_quote}{close_quote} behavior is expected. {copyright} {ital 1996 The American Physical Society.}

Circumstantial evidence for critical behavior in peripheral {ital A}{ital u}{bold +}{ital A}{ital u} collisions at 35 MeV/nucleon

The fragmentation resulting from peripheral Au + Au collisions at an incident energy of {ital E}=35 MeV/nucleon is investigated. A power-law charge distribution, {ital A}{sup {minus}{tau}} with {tau}{approx_equal}2.2, and an intermittency signal are observed for events selected in the region of the Campi scatter plot where {open_quote}{open_quote}critical{close_quote}{close_quote} behavior is expected. {copyright} {ital 1996 The American Physical Society.}

Nuclear temperature measurements with helium isotopes

Abstract Temperatures extracted with the family of ( 3 He , 4 He ) isotope ratio thermometers, THe, have been studied and cross-checked with temperatures, T( 4 He ∗ ) constructed from excited and ground state populations of 4 He . Empirical correction factors provide baseline corrections for sequential decay effects for THe T( 4 He ∗ ) should agree.

Fragment emission from modestly excited nuclear systems

Abstract Fragment emission patterns occurring in nuclear systems of modest excitation are studied. Exclusive measurement of fragment emission in 14 N+ 197 Au reactions at E A = 100, 130 and 156 MeV allows selection of central collisions where a single source dominates the decay. Low threshold measurement of IMF emission for these events allows investigation of the influence of detector threshold effects. The time scale of fragment emission is deduced using fragment-fragment velocity correlations. Comparisons are made to the predictions of a statistical decay model.

Statistical interpretation of the correlation between intermediate mass fragment multiplicity and transverse energy

Multifragment emission following {sup 129}Xe+{sup 197}Au collisions at 30A, 40A, 50A, and 60A MeV has been studied with multidetector systems covering nearly 4{pi} in solid angle. The correlations of both the intermediate mass fragment and light charged particle multiplicities with the transverse energy are explored. A comparison is made with results from a similar system {sup 136}Xe+{sup 209}Bi at 28A MeV. The experimental trends are compared to statistical model predictions. {copyright} {ital 1999} {ital The American Physical Society}

Multifragment emission times in Xe induced reactions

Abstract Multifragment emission is studied in 129 Xe + nat Cu reactions. The emission process for central collisions occurs on a time scale of ≈ 200 fm/c at 30 MeV/n. Intermediate-mass-fragment yields, velocity correlation functions and emission velocities of Z=6 fragments are compared with predictions of statistical decay models.