Q & A Experiment to Search for Vacuum Dichroism, Pseudoscalar-Photon Interaction and Millicharged Fermions
| dc.creator | Chen, Sheng-Jui | |
| dc.creator | Mei, Hsien-Hao | |
| dc.creator | Ni, Wei-Tou | |
| dc.date | 2006-11-28 | |
| dc.date.accessioned | 2026-07-07T11:21:58Z | |
| dc.date.available | 2026-07-07T11:21:58Z | |
| dc.description | A number of experiments are underway to detect vacuum birefringence and dichroism -- PVLAS, Q & A, and BMV. Recently, PVLAS experiment has observed optical rotation in vacuum by a magnetic field (vacuum dichroism). Theoretical interpretations of this result include a possible pseudoscalar-photon interaction and the existence of millicharged fermions. Here, we report the progress and first results of Q & A (QED [quantum electrodynamics] and Axion) experiment proposed and started in 1994. A 3.5-m high-finesse (around 30,000) Fabry-Perot prototype detector extendable to 7-m has been built and tested. We use X-pendulums and automatic control schemes developed by the gravitational-wave detection community for mirror suspension and cavity control. To polarize the vacuum, we use a 2.3-T dipole permanent magnet, with 27-mm-diameter clear borehole and 0.6-m field length,. In the experiment, the magnet is rotated at 5-10 rev/s to generate time-dependent polarization signal with twice the rotation frequency. Our ellipsometer/polarization-rotation-detection-system is formed by a pair of Glan-Taylor type polarizing prisms with extinction ratio lower than 10-8 together with a polarization modulating Faraday Cell with/without a quarter wave plate. We made an independent calibration of our apparatus by performing a measurement of gaseous Cotton-Mouton effect of nitrogen. We present our first experimental results and give a brief discussion of our experimental limit on pseudo-scalar-photon interaction and millicharged fermions. | |
| dc.description | 21 pages, 13 figures, submitted to Modern Physics Letters | |
| dc.identifier | https://arxiv.org/abs/hep-ex/0611050 | |
| dc.identifier | http://arxiv.org/abs/hep-ex/0611050 | |
| dc.identifier | Mod.Phys.Lett.A22:2815-2831,2007 | |
| dc.identifier | doi:10.1142/S0217732307025844 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/194423 | |
| dc.subject | High Energy Physics - Experiment | |
| dc.subject | Astrophysics | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.title | Q & A Experiment to Search for Vacuum Dichroism, Pseudoscalar-Photon Interaction and Millicharged Fermions | |
| dc.type | text |