Search Results (5 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)].

Calculations are presented of the E1 amplitude expected in forbidden M1 transitions of Cs if parity conservation is violated in the neutral weak e-N interaction, as proposed in a number of gauge models, including that of Weinberg and Salam. Valence electron wave functions are generated as numerical solutions of the Dirac equation in a Tietz central potential, and are used to calculate excited-state lifetimes, hfs splittings, and Stark E1 transition amplitudes. These are compared with experiment and are in good agreement. Contributions to the 6²S_{1 / 2} g-factor anomaly and to the forbidden 6²S_{1 / 2}-7²S_{1 / 2} and 6²S_{1 / 2}-8²S_{1 / 2} transitions from relativistic effects, Breit interaction, interconfiguration interaction, and hfs mixing are calculated, and it is found that this theoretical description is not entirely adequate. The parity-nonconserving E1 amplitude E_PN for the 6²S_{1 / 2}-7²S_{1 / 2} and 6²S_{1 / 2}-8²S_{1 / 2} transitions is evaluated. The results E_PN(6S-7S)=i3.50×10^-11 Q_W|μ_B| and E_PN(6S-8S)=i1.48×10^-11Q_W|μ_B| are obtained. With a measured value of the M1 amplitude M_expt and the Weinberg value Q_W=-99, we find a circular dichroism δ=1.64×10^-4 for the 6²S_{1 / 2}-7²S_{1 / 2} transition.

Calculations are presented of the E1 amplitude expected in the 6²P_{1 / 2}-7²P_{1 / 2} forbidden M1 transition in Tl if parity conservation is violated in the neutral weak e-N interaction, as proposed in a number of gauge models, including that of Weinberg and Salam. Valence-electron wave functions are generated as numerical solutions to the Dirac equation in a modified Tietz central potential. These wave functions are used to calculate allowed E1 oscillator strengths, hfs splittings, and Stark E1 transition amplitudes. These results are compared with experiment and the agreement is generally good. The relativistic 6²P_{1 / 2}-7²P_{1 / 2} M1 transition amplitude m is also calculated, and corrections due to interconfiguration mixing, Breit interaction, and hfs mixing are included. The result, m_theor=(-3.2±1.0)×10^-5|e|ℏ / 2m_ec, is in agreement with the experimental value, m_expt=(-2.11±0.30)×10^-5|e|ℏ / 2m_ec. The parity-nonconserving E1 amplitude E_PN is calculated, and a value for the circular dichroism, δ≃2Im(E_PN,theo) / m_expt=2.6×10^-3, is obtained. Parity-nonconserving effects in other Tl transitions are discussed.