High-energy γ-rays from the decay of the giant-dipole resonance (GDR) in the hot
106Sn compound nucleus and its daughters were measured in coincidence with heavy recoiling evaporation residues. The ...compound nucleus was formed at excitation energy
E
∗ = 80
MeV
using the reaction
56Ni+
48Ti at a bombarding energy of 260 MeV. The analysis yields the GDR width for two different intervals of angular momentum 〈
J〉 = 24 and 36ℏ. The present data, combined with previous data at higher angular momentum permit a study of the angular momentum dependence of the GDR width for 10 ⩽
J ⩽ 60ℏ at approximately fixed temperature. The width of the GDR is found to be roughly constant for
J < 35ℏ, increasing rapidly for higher angular momenta. The data are found to be in good agreement with theoretical calculations within an adiabatic model describing thermal fluctuations of the nuclear shape. The model also reproduces the much weaker angular momentum dependence of the GDR width in the heavier nucleus
176W.
Scanning the phases of QCD with BRAHMS Murray, Michael; Collaboration, the BRAHMS
Journal of Physics G: Nuclear and Particle Physics,
08/2004, Letnik:
30, Številka:
8
Journal Article, Conference Proceeding
The forward high $p_{\rm T}$ puzzle Gaardhøje, J. J.
The European physical journal. C, Particles and fields,
08/2005, Letnik:
43, Številka:
1-4
Journal Article
The invariant cross section as a function of transverse momentum for antideuterons produced in 158A GeV/c per nucleon Pb+Pb central collisions has been measured by the NA44 experiment at CERN. This ...measurement, together with a measurement of antiprotons, allows for the determination of the antideuteron coalescence parameter. The extracted coalescence radius is found to agree with the deuteron coalescence radius and radii determined from two particle correlations.
The γ-decay of the GDR in hot Hg and Eu isotopes has been measured in coincidence with selected low-energy γ-transitions of the evaporation residues.
In the Hg case, the GDR width at finite ...temperature and at different spins was studied by analyzing simultaneously with the statistical model the high-energy γ-ray spectra associated with different residual nuclei and the fractions of residue cross-sections. The measured GDR width was found in good agreement with the predictions of the thermal fluctuations model.
In the case of Eu, we have measured the high-energy γ-rays in coincidence with low-energy γ-transitions from different nuclear configurations of
143Eu in order to search for the GDR decay built on a superdeformed state. The analysis of the data shows a possible evidence of this state. The measured intensity indicates that the superdeformation survives only few MeV above the yrast line.
Gamma rays emitted from hot nuclei with mass around 115 and excitation energies between 350 and 500 MeV, formed in the sup 36Ar + sup 90Zr reaction at 27 MeV/nucleon have been measured. The gamma-ray ...yield from the decay of the giant dipole resonance in these nuclei remains constant over the excitation energy range studied. This quenching of the gamma multiplicity cannot be explained by a continuous increase with temperature of the width of the resonance. Better agreement with the data is obtained by assuming a cutoff of gamma emission from the resonance above an excitation energy of 250 MeV. The existing data do not show entrance channel effects.
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