D. M. Lazarus

Search for photon regeneration in a magnetic field

We have searched for the regeneration of photons propagating in a transverse magnetic field. Such an effect would reveal the existence of light scalar or pseudoscalar particles such as the axion that couple to two photons. We obtain for this coupling the limitgaγγ<(1.3×106 GeV)−1, provided the axion massma≲10−3 eV.

Measurements of polarization in K−p elastic scattering at low energies

Abstract The polarization parameter has been measured in K−p elastic scattering at eight incident beam momenta between 650 MeV/c and 1071 MeV/c throughout a center of mass angular range of −0.75 cos θ ∗ . Experimental results and coefficients of Legendre polynomial fits to the data are presented and compared with other measurements and partial wave analysis.

Coherent production/detection of light scalars/pseudoscalars and QED vacuum polarization

We searched for light scalars/pseudoscalars (e.g., axions) that couple to two photons using three different techniques: (1) Optical rotation, where a polarized laser beam enters a dipole magnetic field region. The production of scalars/pseudoscalars has an effect the rotation of the polarization which is detected by an analyzer system giving a limit [ital g][sub [alpha][gamma][gamma]][lt]3.6[times]10[sup [minus]7] GeV[sup [minus]1], for [ital m][sub [ital a]][lt]10[sup [minus]3] eV. (2) Photon regeneration experiment, where the particles are generated in one magnet by the polarized laser beam, travel through a wall and reconvert back to the original photons inside another magnet where they are detected by a photomultiplier, giving a limit to [ital g][sub [alpha][gamma][gamma]][lt]6.7[times]10[sup [minus]7] GeV[sup [minus]1] for the same mass range as above. (3) Finally we searched for scalars/pseudoscalars coming from the sun, looking at the back of a dipole magnet pointing at the setting sun, with an x-ray detector. The limit obtained this way is [ital g][sub [alpha][gamma][gamma]][lt]3.7[times]10[sup [minus]9] GeV[sup [minus]1], provided [ital m][sub [ital a]][lt]0.1 eV.