Demonstration of Deuterium’s Enhanced Sensitivity to Symmetry Violations Governed by the Standard-Model Extension

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We have performed hyperfine spectroscopy of two transitions in ground-state deuterium and searched for violations of <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mrow> <a:mi>C</a:mi> <a:mi>P</a:mi> <a:mi>T</a:mi> </a:mrow> </a:math> and Lorentz symmetry that would manifest as sidereal variations of the observed transition frequencies. Several nonrelativistic proton coefficients of the Standard-Model extension framework have been addressed. The spin-independent coefficients with momentum power <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>k</c:mi> <c:mo>=</c:mo> <c:mn>2</c:mn> </c:math> , 4 are constrained for the first time. Bounds on spin-dependent coefficients are improved by exploiting a sensitivity enhancement originating from the relative momenta of the nucleons in the deuteron. The best previous constraints by hydrogen maser measurements are surpassed by 4 and 14 orders of magnitude for coefficients with <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi>k</e:mi> <e:mo>=</e:mo> <e:mn>2</e:mn> </e:math> and 4, respectively.