A Logarithmic, Large-Solid-Angle Detector Telescope for Nuclear Fragmentation

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Complex Fragment Emission in Coincidence with Angle-Correlated Fission Fragments in the 270 MeV 3-He + 232-Th System

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Emission of Intermediate Mass Fragments Normal to the Fission Axis in Hot Heavy Nuclei

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Search for Multifragmentation Near Threshold in the 3-He + Ag Reaction

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Multifragment Emission in the 3-He + nat-Hg Reaction at 0.90 and 3.6 GeV

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Nonequilibrium Slope Temperatures for IMF Emission in the E/A = 20-100 MeV 14-N + 197-Au Reactions

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Emissioin of Intermediate Mass Fragments During Fission

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

IMF Emission in the 14-N + nat-Ag, Au Reactions at E/A = 60-100 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Study of intermediate velocity products in the Ar+Ni collisions between 52 and 95 A.MeV

Intermediate velocity products in Ar+Ni collisions from 52 to 95 A.MeV are studied in an experiment performed at the GANIL facility with the 4$\pi$ multidetector INDRA. It is shown that these emissions cannot be explained by statistical decays of the quasi-projectile and the quasi-target in complete equilibrium. Three methods are used to isolate and characterize intermediate velocity products. The total mass of these products increases with the violence of the collision and reaches a large fraction of the system mass in mid-central collisions. This mass is found independent of the incident energy, but strongly dependent on the geometry of the collision. Finally it is shown that the kinematical characteristics of intermediate velocity products are weakly dependent on the experimental impact parameter, but strongly dependent on the incident energy. The observed trends are consistent with a participant-spectator like scenario or with neck emissions and/or break-up.Comment: 37 pages, 13 figure

Two-loop O(GF2MH4){\rm O}\left(G_F^2M_H^4\right) corrections to the fermionic decay rates of the Higgs boson

We calculate the dominant ${\rm O}\left(G_F^2M_H^4\right)$ two-loop electroweak corrections to the fermi\-onic decay widths of a heavy Higgs boson in the Standard Model. Use of the Goldstone-boson equivalence theorem reduces the problem to one involving only the physical Higgs boson $H$ and the Goldstone bosons $w^\pm$ and $z$ of the unbroken theory. The two-loop corrections are opposite in sign to the one-loop electroweak corrections, exceed the one-loop corrections in magnitude for $M_H>1114\ {\rm GeV}$, and increase in relative magnitude as $M_H^2$ for larger values of $M_H$. We conclude that the perturbation expansion in powers of $G_FM_H^2$ breaks down for $M_H\approx 1100\ {\rm GeV}$. We discuss briefly the QCD and the complete one-loop electroweak corrections to $H\rightarrow b\bar{b}, \,t\bar{t}$, and comment on the validity of the equivalence theorem. Finally we note how a very heavy Higgs boson could be described in a phenomenological manner.Comment: 24 pages, RevTeX file, 4 figures in a separate compressed uuencoded Postscript file or available by mail on request. Fig. 1 not included see Figs. 1, 2 in Phys. Rev. D 48, 1061 (1993