First search for invisible decays of orthopositronium confined in a vacuum cavity

While our visible Universe could be a 3-brane, some cosmological scenarios consider that other 3-branes could be hidden in the extra-dimensional bulk. Matter disappearance toward a hidden brane is mainly discussed for neutron — both theoretically and experimentally — but other particles are poorly studied. Recent experimental results offer new constraints on positronium or quarkonium invisible decays. In the present work, we show how a two-brane Universe allows for such invisible decays. We put this result in the context of the recent experimental data to constrain the brane energy scale [Formula: see text] (or effective brane thickness [Formula: see text]) and the interbrane distance [Formula: see text] for a relevant two-brane Universe in a [Formula: see text]-broken 5D bulk. Quarkonia present poor bounds compared to the results deduced from previous passing-through-walls-neutron experiments for which scenarios with [Formula: see text] GeV and [Formula: see text] fm are excluded. By contrast, positronium experiments can compete with neutron experiments depending on the matter content of each brane. To constrain scenarios up to the Planck scale, positronium experiments in vacuum cavity should be able to reach [Formula: see text].

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Constraints on New Physics in Electron g−2 from a Search for Invisible Decays of a Scalar, Pseudoscalar, Vector, and Axial Vector

Physical Review Letters ◽

10.1103/physrevlett.126.211802 ◽

2021 ◽

Vol 126 (21) ◽

Author(s):

Yu. M. Andreev ◽

D. Banerjee ◽

J. Bernhard ◽

V. E. Burtsev ◽

A. G. Chumakov ◽

...

Keyword(s):

Axial Vector ◽

New Physics ◽

Invisible Decays

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Influence of a centrifugal field on the residual pressure in the vacuum cavity of a rotating helium cryostat

Journal of Engineering Physics ◽

10.1007/bf00861929 ◽

1979 ◽

Vol 36 (3) ◽

pp. 361-363

Author(s):

I. A. Tsimmerman ◽

A. D. Shvets

Keyword(s):

Residual Pressure ◽

Centrifugal Field ◽

Helium Cryostat ◽

Vacuum Cavity

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Fusion of W states in a cavity quantum electrodynamic system

Canadian Journal of Physics ◽

10.1139/cjp-2014-0096 ◽

2015 ◽

Vol 93 (5) ◽

pp. 556-560 ◽

Cited By ~ 9

Author(s):

Xue-Ping Zang ◽

Ming Yang ◽

Xian-Cai Wang ◽

Wei Song ◽

Zhuo-Liang Cao

Keyword(s):

Quantum Electrodynamic ◽

Cavity Mode ◽

State System ◽

The Other ◽

W State ◽

Feasibility Analysis ◽

Electrodynamic System ◽

W States ◽

Vacuum Cavity

In this paper, we study how to fuse two W states into a larger W state in a cavity quantum electrodynamic system. Two atoms are collided within a detuned vacuum cavity mode. One atom is from the first N-atom W state system, and the other is from the second M-atom W state system. The two atoms will be detected after flying out of the cavity mode. If only one excitation is detected between the two atoms, an (N + M − 2)-atom W state can be generated with some probability. If no excitation is detected between the two atoms, the remaining (N − 1)-atom W state and (M − 1)-atom W state can be re-fused using the same procedure, continuing until two excitations are detected between the two atoms. Using this procedure, the chance of entanglement of the two W states is as large as possible. A feasibility analysis indicates that this scheme can be implemented using existing experimental technologies.

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Measurement of Shear Stress and Temperature Using MEMS Fabricated Sensors

10.1115/imece1999-0272 ◽

1999 ◽

Author(s):

Kenneth S. Breuer ◽

Robert L. Bayt ◽

Anju Nayaar

Keyword(s):

Shear Stress ◽

Silicon Nitride ◽

Temperature Sensors ◽

Test Results ◽

Thin Membrane ◽

Sensor Element ◽

Successful Operation ◽

Thermal Isolation ◽

Varying Length ◽

Vacuum Cavity

Abstract The design, fabrication and testing of microfabricated thermal shear stress and temperature sensors are sensors is discussed. The devices are fabricated on a silicon substrate with a platinum sensor element 5 microns wide, 1000-Å thick and of varying length. The electrical leads are comprised of 5000-Å of gold deposited above the platinum sensor metal. The sensing area is isolated from the substrate by a thin membrane of silicon nitride covering a vacuum cavity. Test results are presented confirming the good thermal isolation of the sensor element from the substrate as well as the successful operation of the device.

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