arXiv subjects

Alan J. Weinstein

Publications and source records attributed to Alan J. Weinstein.

23 records · Page 2Linked to original sources

arXiv2008

A Quantum-Enhanced Prototype Gravitational-Wave Detector

The quantum nature of the electromagnetic field imposes a fundamental limit on the sensitivity of optical precision measurements such as spectroscopy, microscopy, and interferometry. The so-called quantum limit is set by the zero-point fluctuations of the electromagnetic field, which constrain the precision with which optical signals can be measured. In the world of precision measurement, laser-interferometric gravitational wave (GW) detectors are the most sensitive position meters ever operated, capable of measuring distance changes on the order of 10^-18 m RMS over kilometer separations caused by GWs from astronomical sources. The sensitivity of currently operational and future GW detectors is limited by quantum optical noise. Here we demonstrate a 44% improvement in displacement sensitivity of a prototype GW detector with suspended quasi-free mirrors at frequencies where the sensitivity is shot-noise-limited, by injection of a squeezed state of light. This demonstration is a critical step toward implementation of squeezing-enhancement in large-scale GW detectors.

quant-ph↗

arXiv2000

Semi-hadronic Tau Decays at CLEO

This contribution reviews several new or updated results on substructure in semi-hadronic tau decays, recently published by the CLEO Collaboration. These results are all based on data collected with the CLEO detector at Cornell's CESR collider, in the reaction $e^+e^-\to τ^+τ^-$ at $\sqrt{s} \simeq 10.6$ GeV. Most of these results are based on $\approx 4.3\times 10^6$ $τ^+τ^-$ pairs collected with the CLEO II detector between 1990 --- 1995. Some (where noted) also use $\approx 8.0\times 10^6$ $τ^+τ^-$ pairs collected with the CLEO II.V detector (which includes a silicon vertex detector and better drift chamber tracking) between 1995 --- 1999.

hep-ex↗

arXiv1999

Tau Electroweak Couplings

We review world-average measurements of the tau lepton electroweak couplings, in both decay (including Michel parameters) and in production ($Z^0\to τ^+τ^-$ and $W^-\toτ^-\nubar_τ$). 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.

hep-ex↗

arXiv1998

CLEO Results on Tau Michel Parameters

We present measurements of the tau Michel Parameters made by the CLEO experiment. Three different analyses are performed: a spin-independent lepton spectrum analysis and a second spin-dependent analysis using $\ell^\pm$ \vs\ $π^\mpπ^0$ events, and a third spin-dependent analysis using $π^+$ \vs\ $π^-$ events. the results are used to derive limits on the general four-fermion couplings, the mass of the charged Higgs in the MSSM, and a right-handed $W$ in left-right models. Many of these measurements are more precise than the PDG world averages.

hep-ex↗

arXiv1998

TAU 98 Conference Summary

I very briefly review the highlights of the fifth workshop on the physics of the tau lepton and its neutrino. There has been much progress in many sub-fields, which I touch upon in this review: the couplings of the tau to the $Z^0$ and $W^\pm$; the leptonic branching fractions, lifetime, and tests of universality; the Lorentz structure of tau decays; searches for neutrinoless decays; limits on weak and electromagnetic dipole moments and CP violation; inclusive semi-hadronic decays, spectral functions, sum rules, QCD, and applications; substructure in tau decays to three pseudoscalars; tau decays to kaons; limits on the mass of the tau neutrino; tau neutrinos from solar, atmospheric, and AGN sources; accelerator searches for neutrino oscillations; and prospects for the future.

hep-ex↗