Frankfurt 2014 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 9: Fundamentale Symmetrien
HK 9.2: Group Report
Monday, March 17, 2014, 17:00–17:30, HZ 3
New limit on Lorentz and CPT violating neutron spin interactions using a free precession 3He-129Xe co-magnetometer — •Fabian Allmendinger1, Ulrich Schmidt1, Werner Heil2, Sergei Karpuk2, Anja Scharth2, Yuri Sobolev2, Kathlynne Tullney2, and Stefan Zimmer2 for the He-Xe-comagnetometer collaboration — 1Physikalisches Institut, Ruprecht-Karls-Universität, 69120 Heidelberg, Germany — 2Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany
We performed a search for a CPT and Lorentz invariance violating coupling of the 3He and 129Xe nuclear spins (each largely determined by a valence neutron) to background tensor fields which permeate the universe. Our experimental approach is to measure the free precession of nuclear spin polarized 3He and 129Xe 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 co-located 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 < 6.7 · 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 5. In the talk we will give an overview of the principle of measurement and current results.