The Partial Beam Lifetime at RHIC due to Coulomb Dissociation of the Nucleus

During beam crossing at RHIC, the Lorentz contracted Coulomb interaction between the heavy ions will excite internal modes of the nucleus. The subsequent decay of these modes is predominately via single or multiple nucleon emission. Changing the atomic mass Of the beam ion will eventually cause beam intensity loss at RHIC for the radius of the ion orbit is sensitive to changes of the ratio Z/A. While calculations for this beam loss mechanism have been made, it is now clear that these earlier theoretical studies underestimated the Coulomb dissociation loss rate for they appear to have included only a limited range of internal nuclear excitation energy. In this report we reexamine the question of Coulomb dissociation cross sections at RHIC by including internal excitation energies up to thousands of GeV. In addition, we utilize experimental photonuclear absorption cross sections when evaluating the dissociation cross section. Also, internal excitation of a nucleus in one beam wig result in both energy loss and transverse momentum change of an ion in the colliding beam. These recoil effects will be examined in detail to determine if there is an additional loss rate for ions out of the rf bucket or a non-negligible change in the ion's betatron momentum

The GALLEX Project

AbstractThe GALLEX collaboration aims at the detection of solar neutrinos in a radiochemical experiment employing 30 tons of Gallium in form of concentrated aqueous Gallium-chloride solution. The detector is primarily sensitive to the otherwise inaccessible pp-neutrinos. Details of the experiment have been repeatedly described before [1-7]. Here we report the present status of implementation in the Laboratori Nazionali del Gran Sasso (Italy). So far, 12.2 tons of Gallium are at hand. The present status of development allows to start the first full scale run at the time when 30 tons of Gallium become available. This date is expected to be January, 1990

Matter Oscillations: Neutrino Transformation and Regeneration in the Earth

Transformation and regeneration phenomena are calculated to result from transmission through the Earth of neutrinos with E(MeV)/..delta..m/sup 2/(eV)/sup 2/ in the vicinity of 10/sup 6/ to 10/sup 7/. As a result, large time-of-night and seasonal variations are predicted for various solar neutrino experiments in this parameter range. Analagous effects are predicted for terrestrial cosmic ray and accelerator experiments

Mutual dressing of bare relativistic heavy ions during transit in collider orbits. I. General considerations

In the interaction regions of a relativistic heavy-ion collider, bare, highly charged nuclei pass at great velocities, oppositely moving similar nuclei. Each nucleus, then, sees strong, time varying electromagnetic fields, and it is not surprising that there is a large probability for electron-positron pair creation (a process evaluated many years ago). There is also a smaller probability that the electron of the pair is created, not in a continuum state, but in one of the bound orbits, the K or L or higher orbits, of the Coulomb field of the previously bare nuclei. This dressing is most unfortunate for a collider device, since the charge change leaves the nucleus in an orbit that is no longer appropriate for continuing circulation. This note evaluates the probability for such dressing, and also examines whether a subsequent sweep-off process can undo the first step with any sizeable likelihood. 3 references

Specificity of /sup 71/Ga(p,n)/sup 71/Ge at 35 MeV for Gamow-Teller Strength

The motivation for considering the /sup 71/Ga(p,n)/sup 71/Ge reaction is to help determine the properties of /sup 71/Ga as a detector of solar neutrinos. The proposed solar neutrino experiment, /sup 71/Ga(nu,e/sup -/)/sup 71/Ge, has a threshold of only .236 MeV, and is thus sensitive to neutrinos produced in the basic burning process in the sun p + p ..-->.. /sup 2/H + e/sup +/ + nu, which has a .420 MeV endpoint. The excitation of the (5/2)/sup -/ state at .175 MeV in /sup 71/Ge could be important, however. Were the Gamow-Teller (G-T) transition to the 175 keV state equal in strength to the ground state transition there would be approx. 25% added to the detector signal, the greater part of this coming from the /sup 7/Be neutrinos; the desired sensitivity to the p-p neutrinos would then be less