38 research outputs found
Muon Collider Overview: Progress and Future Plans
Besides continued work on the parameters of a 3-4 and 0.5 TeV CoM collider,
many studies are now concentrating on a machine near 100 GeV that could be a
factory for the s-channel production of Higgs particles. We mention 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 channel, muon cooling,
acceleration, storage in a ring and the collider detector. We also mention
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 note is a summary of a report updating the progress on the
R&D since the Feasibility Study of Muon Colliders presented at the Workshop
Snowmass'96.Comment: 3 pages, 2 figures, LaTex EPAC format; to be published Proceedings of
the EPAC98 Conference, Stockholm, Sweden, June 1998. Additional information
and articles at http://www.cap.bnl.gov/mumu
Probing Non-Standard Neutrino Interactions with Neutrino Factories
We discuss the sensitivity reach of a neutrino factory measurement to
non-standard neutrino interactions (NSI), which may exist as a low-energy
manifestation of physics beyond the Standard Model. We use the muon appearance
mode \nu_e --> \nu_\mu and consider two detectors, one at 3000 km and the other
at 7000 km.
Assuming the effects of NSI at the production and the detection are
negligible, we discuss the sensitivities to NSI and the simultaneous
determination of \theta_{13} and \delta by examining the effects in the
neutrino propagation of various systems in which two NSI parameters
\epsilon_{\alpha \beta} are switched on. The sensitivities to off-diagonal
\epsilon's are found to be excellent up to small values of \theta_{13}.
We demonstrate that the two-detector setting is powerful enough to resolve
the \theta_{13}-NSI confusion problem. We believe that the results obtained in
this paper open the door to the possibility of using neutrino factory as a
discovery machine for NSI while keeping its primary function of performing
precision measurements of the lepton mixing parameters.Comment: 47 pages, 22 figures. Color version of Figs. 18, 19 and 22 can be
found in the article published in JHE
From parameter space constraints to the precision determination of the leptonic Dirac CP phase
We discuss the precision determination of the leptonic Dirac CP phase
in neutrino oscillation experiments, where we apply the concept
of ``CP coverage''. We demonstrate that this approach carries more information
than a conventional CP violation measurement, since it also describes the
exclusion of parameter regions. This will be very useful for next-generation
long baseline experiments where for sizable first
constraints on can be obtained. As the most sophisticated
experimental setup, we analyze neutrino factories, where we illustrate the
major difficulties in their analysis. In addition, we compare their potential
to the one of superbeam upgrades and next-generation experiments, which also
includes a discussion of synergy effects. We find a strong dependence on the
yet unknown true values of and , as well as
a strong, non-Gaussian dependence on the confidence level. A systematic
understanding of the complicated parameter dependence will be given. In
addition, it is shown that comparisons of experiments and synergy discussions
do in general not allow for an unbiased judgment if they are only performed at
selected points in parameter space. Therefore, we present our results in
dependence of the yet unknown true values of and
. Finally we show that for precision measurements
there exist simple strategies including superbeams, reactor experiments,
superbeam upgrades, and neutrino factories, where the crucial discriminator is
.Comment: 32 pages, 9 figure
Neutral currents and tests of three-neutrino unitarity in long-baseline experiments
We examine a strategy for using neutral current measurements in long-baseline
neutrino oscillation experiments to put limits on the existence of more than
three light, active neutrinos. We determine the relative contributions of
statistics, cross section uncertainties, event misidentification and other
systematic errors to the overall uncertainty of these measurements. As specific
case studies, we make simulations of beams and detectors that are like the K2K,
T2K, and MINOS experiments. We find that the neutral current cross section
uncertainty and contamination of the neutral current signal by charge current
events allow a sensitivity for determining the presence of sterile neutinos at
the 0.10--0.15 level in probablility.Comment: 24 pages, Latex2e, uses graphicx.sty, 2 postscript figures. Submitted
to the Neutrino Focus Issue of New Journal Physics at http://www.njp.or
Lower limit on the neutralino mass in the general MSSM
We discuss constraints on SUSY models with non-unified gaugino masses and R_P
conservation. We derive a lower bound on the neutralino mass combining the
direct limits from LEP, the indirect limits from gmuon, bsgamma, Bsmumu and the
relic density constraint from WMAP. The lightest neutralino (mneutralino=6GeV)
is found in models with a light pseudoscalar with MA<200GeV and a large value
for . Models with heavy pseudoscalars lead to mneutralino>18(29)GeV
for . We show that even a very conservative bound from the
muon anomalous magnetic moment can increase the lower bound on the neutralino
mass in models with mu<0 and/or large values of . We then examine
the potential of the Tevatron and the direct detection experiments to probe the
SUSY models with the lightest neutralinos allowed in the context of light
pseudoscalars with high . We also examine the potential of an e+e-
collider of 500GeV to produce SUSY particles in all models with neutralinos
lighter than the W. In contrast to the mSUGRA models, observation of at least
one sparticle is not always guaranteed.Comment: 37 pages, LateX, 16 figures, paper with higher resolution figures
available at
http://wwwlapp.in2p3.fr/~boudjema/papers/bound-lsp/bound-lsp.htm
hep-ph/9802368 Narrow Technihadron Production
In modern technicolor models, there exist very narrow spin-zero and spin-one neutral technihadrons—π 0 T, ρ0 T and ωT—with masses of a few 100GeV. The large coupling of π 0 T to µ+ µ − , the direct coupling of ρ 0 T and ωT to the photon and Z 0, and the superb energy resolution of the First Muon Collider may make it possible to resolve these technihadrons and produce them at extraordinarily large rates