27,581 research outputs found
Tau Electroweak Couplings
We review world-average measurements of the tau lepton electroweak couplings,
in both decay (including Michel parameters) and in production ( and W^-\to\tau^-\nubar_\tau). We review the searches for
anomalous weak and EM dipole couplings. Finally, we present the status of
several other tau lepton studies: searches for lepton flavor violating decays,
neutrino oscillations, and tau neutrino mass limits.Comment: 12 pages, 16 figures; talk presented at Heavy Flavours 8,
Southampton, UK, 199
Probing gravitational wave polarizations with signals from compact binary coalescences
In this technical note, we study the possibility of using networks of
ground-based detectors to directly measure gravitational-wave polarizations
using signals from compact binary coalescences. We present a simple data
analysis method to partially achieve this, assuming presence of a strong signal
well-captured by a GR template.Comment: Technical not
On the Kottwitz conjecture for local Shimura varieties
Kottwitz’s conjecture describes the contribution of a supercuspidal represention to the cohomology of a local Shimura variety in terms of the local Langlands correspondence. Using a Lefschetz-Verdier fixedpoint formula, we prove a weakened generalized version of Kottwitz’s conjecture. The weakening comes from ignoring the action of the Weil group and only considering the actions of the groups G and Jb up to non-elliptic representations. The generalization is that we allow arbitrary connected reductive groups G and non-minuscule coweights µ
Experimental Limits on Weak Annihilation Contributions to b → ulv Decays
We present the first experimental limits on high-q^2 contributions to charmless semileptonic B decays of the form expected from the weak annihilation (WA) decay mechanism. Such contributions could bias determinations of |V_(ub)| from inclusive measurements of B→X_ulν. Using a wide range of models based on available theoretical input we set a limit of Γ_(WA)/Γ_(b→u) <7.4% (90% confidence level) on the WA fraction, and assess the impact on previous inclusive determinations of |V_(ub)|
Demonstration of ultra-high-Q small mode volume toroid microcavities on a chip
Optical microcavities confine light spatially and temporally and find
application in a wide range of fundamental and applied studies. In many areas,
the microcavity figure of merit is not only determined by photon lifetime (or
the equivalent quality-factor, Q), but also by simultaneous achievement of
small mode volume V . Here we demonstrate ultra-high Q-factor small mode volume
toroid microcavities on-a-chip, which exhibit a Q/V factor of more than
. These values are the highest reported to date for any
chip-based microcavity. A corresponding Purcell factor in excess of 200 000 and
a cavity finesse of is achieved, demonstrating that toroid
microcavities are promising candidates for studies of the Purcell effect,
cavity QED or biochemical sensingComment: 4 pages, 3 figures, Submitted to Applied Physics Letter
Measurement of turbulent correlations in a coaxial flow of dissimilar fluids
Axial turbulence measurements in coaxial flow of dissimilar gase
Trapping radioactive ^{82}Rb in an optical dipole trap and evidence of spontaneous spin polarization
Optical trapping of selected species of radioactive atoms has great potential
in precision measurements for testing fundamental physics such as EDM, PNC and
parity violating beta-decay asymmetry correlation coefficients. We report
trapping of 10^4 radioactive ^{82}Rb atoms (t_{1/2}=75 s) with a trap lifetime
of ~55 seconds in an optical dipole trap. Transfer efficiency from the
magneto-optical trap was ~14%. We further report the evidence of spontaneous
spin polarization of the atoms in optical dipole trap loading. This advancement
is an important step towards a new generation of precision J-beta correlations
measurements with polarized ^{82}Rb atoms.Comment: 4 pages, 4 figure
Geometric quantization of Hamiltonian actions of Lie algebroids and Lie groupoids
We construct Hermitian representations of Lie algebroids and associated
unitary representations of Lie groupoids by a geometric quantization procedure.
For this purpose we introduce a new notion of Hamiltonian Lie algebroid
actions. The first step of our procedure consists of the construction of a
prequantization line bundle. Next, we discuss a version of K\"{a}hler
quantization suitable for this setting. We proceed by defining a
Marsden-Weinstein quotient for our setting and prove a ``quantization commutes
with reduction'' theorem. We explain how our geometric quantization procedure
relates to a possible orbit method for Lie groupoids. Our theory encompasses
the geometric quantization of symplectic manifolds, Hamiltonian Lie algebra
actions, actions of families of Lie groups, foliations, as well as some general
constructions from differential geometry.Comment: 40 pages, corrected version 11-01-200
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