title: Improved limit on a temporal variation of mp/me from comparisons of Yb+ and Cs atomic clocks.
abstract: Accurate measurements of different transition frequencies between atomic levels of the electronic and hyperfine structure over time are used to investigate temporal variations of the fine structure constant α and the proton-to-electron mass ratio μ. We measure the frequency of the (2)S1/2→(2)F7/2 electric octupole (E3) transition in (171)Yb(+) against two caesium fountain clocks as f(E3)=642,121,496,772,645.36  Hz with an improved fractional uncertainty of 3.9×10(-16). This transition frequency shows a strong sensitivity to changes of α. Together with a number of previous and recent measurements of the (2)S1/2→(2)D3/2 electric quadrupole transition in (171)Yb(+) and with data from other elements, a least-squares analysis yields (1/α)(dα/dt)=-0.20(20)×10(-16)/yr and (1/μ)(dμ/dt)=-0.5(1.6)×10(-16)/yr, confirming a previous limit on dα/dt and providing the most stringent limit on dμ/dt from laboratory experiments.
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Huntemann
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Lipphardt
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: Chr
authors.initials: C
authors.lastname: Tamm
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Gerginov
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Weyers
authors.affiliation: Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Peik