New limit on Lorentz-invariance- and CPT-violating neutron spin interactions using a free-spin-precession He3-Xe129 comagnetometer.
We report on the search for a CPT- and Lorentz-invariance-violating coupling of the He3 and Xe129 nuclear spins (each largely determined by a valence neutron) to posited background tensor fields that permeate the Universe. Our experimental approach is to measure the free precession of nuclear spin polarized He3 and Xe129 atoms in a homogeneous magnetic guiding field of about 400 nT using LTC SQUIDs as low-noise magnetic flux detectors. As the laboratory reference frame rotates with respect to distant stars, we look for a sidereal modulation of the Larmor frequencies of the colocated spin samples. As a result we obtain an upper limit on the equatorial component of the background field interacting with the spin of the bound neutron b(⊥)(n)<8.4 × 10(-34)  GeV (68% C.L.). Our result improves our previous limit (data measured in 2009) by a factor of 30 and the world's best limit by a factor of 4.
Physikalisches Institut, Ruprecht-Karls-Universität, 69120 Heidelberg, Germany.
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F
Allmendinger
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany.
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W
Heil
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany.
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S
Karpuk
Physikalisch-Technische Bundesanstalt Berlin, 10587 Berlin, Germany.
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W
Kilian
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany.
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A
Scharth
Physikalisches Institut, Ruprecht-Karls-Universität, 69120 Heidelberg, Germany.
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U
Schmidt
Physikalisch-Technische Bundesanstalt Berlin, 10587 Berlin, Germany.
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A
Schnabel
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany.
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Y
Sobolev
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany.
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K
Tullney