Preferred-Frame and CP-Violation Tests with Polarized Electrons

By B. Heckel, E. Adelberger, C. Cramer, T. Cook, Stephan Schlamminger, U. Schmidt. 2007

146 citations recorded by the source corpus.

We used a torsion pendulum containing {approx_equal}10{sup 23} polarized electrons to search new interactions that couple to electron spin. We limit CP-violating interactions between the pendulum's electrons and unpolarized matter in the Earth or the Sun, test for rotation and boost-dependent preferred-frame effects using the Earth's rotation and velocity with respect to the entire cosmos, and search for exotic velocity-dependent potentials between polarized electrons and unpolarized matter in the Sun and Moon. We find CP-violating parameters |g{sub P}{sup e}g{sub S}{sup N}|/(({Dirac_h}/2{pi})c) 1 AU. We test for preferred-frame interactions of the form V=-{sigma}{sup e}{center_dot}A, V=-B{sigma}{sup e}{center_dot}v/c, or , where v is the velocity of the Earth with respect to the cosmic microwave background restframe and i, j represent the equatorial inertial coordinates X, Y, and Z. We constrain all 3 components of A, obtaining 1{sigma} upper limits |A{sub X,Y}|{<=}1.5x10{sup -22} eV and |A{sub Z}|{<=}4.4x10{sup -21} eV that may be compared to the benchmark value m{sub e}{sup 2}/M{sub Planck}=2x10{sup -17} eV. Interpreting our constraint on A in terms of noncommutative geometry, we obtain an upper bound of (355l{sub GUT}){sup 2} on the minimum observable area, where l{sub GUT}=({Dirac_h}/2{pi})c/(10{sup 16} GeV) is the grandmore » unification length. We find that |B|{<=}1.2x10{sup -19} eV. All 9 components of C are constrained at the 10{sup -17} to 10{sup -18} eV level. We determine 9 linear combinations of parameters of the standard model extension; rotational-noninvariant and boost-noninvariant terms are limited at roughly the 10{sup -31} GeV and 10{sup -27} GeV levels, respectively. Finally, we find that the gravitational mass of an electron spinning toward the galactic center differs by less than about 1 part in 10{sup 21} from an electron spinning in the opposite direction. As a byproduct of this work, the density of polarized electrons in Sm Co{sub 5} was measured to be (4.19{+-}0.19)x10{sup 22} cm{sup -3} at a field of 9.6 kG.« less

Subfields: Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/9b40c35b0b2ac6e67c0b147c0cf5961d32190622

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Nuclear and High Energy Physics

In Statistical and Nonlinear Physics

Citations in the corpus

Search for New Physics with Atoms and Molecules (2017, methodology): “, 2012) and a spinpolarized torsion pendulum (Heckel et al., 2008) to derive the limits shown in Fig.”
Tests of Lorentz invariance: a 2013 update (2013, background): “The emission from radio to low-energy γ -rays (E 1 GeV) is thought to be synchrotron radiation from relativistic electrons, whereas IC scattering by these electrons is the favoured explanation for the higher energy γ -rays.”
The Neutron and Its Role in Cosmology and Particle Physics (2011, background): “from Heckel et al. (2008), and from cantilever experiments with small objects for ranges between 2 nm and 1 μm , see Klimchitskaya et al.”