Search Results (9 total)

We describe the status of our effort to realize a first neutrino factory and the progress made in understanding the problems associated with the collection and cooling of muons towards that end. We summarize the physics that can be done with neutrino factories as well as with intense cold beams of muons. The physics potential of muon colliders is reviewed, both as Higgs factories and compact high-energy lepton colliders. The status and time scale of our research and development effort is reviewed as well as the latest designs in cooling channels including the promise of ring coolers in achieving longitudinal and transverse cooling simultaneously. We detail the efforts being made to mount an international cooling experiment to demonstrate the ionization cooling of muons.

The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides work on the parameters of a 3–4 and 0.5 TeV center-of-mass (COM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (COM) that could be a factory for the s-channel production of Higgs particles. We discuss the research on the various components in such muon colliders, starting from the proton accelerator needed to generate pions from a heavy-Z target and proceeding through the phase rotation and decay (π→μν_μ) channel, muon cooling, acceleration, storage in a collider ring, and the collider detector. We also present theoretical and experimental R&D plans for the next several years that should lead to a better understanding of the design and feasibility issues for all of the components. This report is an update of the progress on the research and development since the feasibility study of muon colliders presented at the Snowmass '96 Workshop [R. B. Palmer, A. Sessler, and A. Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics (Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].

A cosmic-ray experiment at Echo Lake, Colorado, employing a liquid hydrogen target, spark chambers, and an ionization calorimeter has been performed to study the interactions of protons with protons above 90 GeV. We report here the results on the angular distribution of the charged secondaries.

A cosmic-ray experiment at Echo Lake, Colorado, employing a 2000-liter liquid-hydrogen target together with spark chambers and an ionization calorimeter has been performed to study the interaction of protons with protons above 70 GeV. We report here the quantitative results on the distribution of secondary charged-particle multiplicity and the energy dependence of the average charged multiplicity.

This paper reports measurements of the total cross section from 150 to 240 Mev of incident photon energy and measurements of the 135° differential cross section from 180 to 215 Mev. A Monte Carlo evaluation of the γ-ray telescope efficiency by means of an electronic digital computer is outlined. The combined results indicate that a small but finite amount of S-state production occurs and that the angular distribution becomes flatter as the energy decreases. The latter effect is associated with production in unenhanced P-states and with a lack of electric quadrupole production. Good agreement with the Chew-Low theory is demonstrated by a comparison between the photoproduction and scattering of π⁰-mesons, where the scattering cross sections are derived from those for charged mesons by charge independence.

The energy losses suffered by 15.7-Mev electrons in traversing samples of about one gram per cm² of absorber in gas and solid form have been measured. Two pairs of absorbers have been used; perfluorocyclobutane gas and its polymer, tetrafluoroethylene resin, "Teflon," and chlorotrifluoroethylene gas and its polymer, "Kel-F" plastic. The losses measured were of the order of one Mev and the resolution of the apparatus made possible an accuracy of 20 kev. The measured losses compared with theoretical predictions are as follows: Teflon—gas 1.33 Mev by experiment and 1.33 Mev by theory, solid 1.27 Mev by experiment and 1.24 Mev by theory; Kel-F—gas 1.29 Mev by experiment and 1.33 Mev by theory, solid 1.09 Mev by experiment and 1.11 Mev by theory.

The most probable energy loss of 9.6- and 15.7-Mev electrons in samples of about one gram per cm² of beryllium, polystyrene, aluminum, copper, and gold has been measured. The losses measured were of the order of one Mev, and the resolution of the apparatus made possible an accuracy of 20 kev. The observed distributions of energy losses are found to be in good agreement with the Landau straggling calculations for the light elements. For the heavier elements there is a spreading of the distribution introduced by radiation and K electron effects. Calculations made by Yang and Kennedy for gold, including these effects, check well with the experimental data.

Applying Fermi's correction for the polarization effect at extreme relativistic velocities to Landau's result for the most probable energy loss, one obtains for the predicted loss in Mev Δ_pc=0.1537D(ΣZ / ΣA)×[19.43+ln(D / ρ)], where D is the absorber thickness in g/cm² and ρ is the absorber density in g/cm³. Experimental results for the light elements are in excellent agreement with this theory. The heavier elements show losses somewhat smaller than those calculated.