Atomic Masses of Tritium and Helium-3

Abstract

By measuring the cyclotron frequency ratios of (3)He(+) to HD(+) and T(+) to HD(+), and using HD(+) as a mass reference, we obtain new atomic masses for (3)He and T. Our results are M[(3)He]=3.016 029 322 43(19) u and M[T]=3.016 049 281 78(19) u, where the uncertainty includes an uncertainty of 0.12 nu in the mass reference. Allowing for cancellation of common systematic errors, we find the Q value for tritium β decay to be (M[T]-M[(3)He])c(2)=18 592.01(7) eV. This allows an improved test of systematics in measurements of tritium β decay that set limits on neutrino mass.

Fundamental Transitions and Ionization Energies of the Hydrogen Molecular Ions with Few ppt Uncertainty

“…As was pointed out already some time ago [3], and recently discussed more extensively [4], if the theory would be sufficiently precise, the spectroscopy of HMI may be used for determining of the fundamental physical constants such as the protonto-electron mass ratio. The ionization energy of HMI is also of high importance for the determination of ionization and dissociation energies of the hydrogen molecule from spectroscopic studies [5][6][7] as well as for the determination of atomic masses of light nuclei [8][9][10].On the experimental side there are many new projects started, which are now oriented towards Doppler-free spectroscopy with accuracy targeted to 1 ppt (one part per trillion) or better [4,[11][12][13]. These perspectives bring strong motivation for theory.…”

“…To this end we consider the largest QED contributions which had not been evaluated in our previous works [14][15][16], namely, corrections to orders mα 6 and mα 7 due to vibrational motion of nuclei and the leading contributions to order mα 8 . As it was shown recently [17], taking into account the vibrational motion of nuclei is essential for accurate theoretical description.…”

“…As was pointed out already some time ago [3], and recently discussed more extensively [4], if the theory would be sufficiently precise, the spectroscopy of HMI may be used for determining of the fundamental physical constants such as the protonto-electron mass ratio. The ionization energy of HMI is also of high importance for the determination of ionization and dissociation energies of the hydrogen molecule from spectroscopic studies [5][6][7] as well as for the determination of atomic masses of light nuclei [8][9][10].…”

Highly sensitive superconducting circuits at ∼700 kHz with tunable quality factors for image-current detection of single trapped antiprotons

“…For instance, the most precise measurements of atomic masses are based on Penning trap experiments [2]. These measurements have impact on neutrino physics [3,4], as well as on stringent tests of relativistic energy-mass equivalence [5]. Electron g-factor measurements provide the most stringent tests of bound-state quantum electrodynamics [6].…”

A pulsed, mono-energetic and angular-selective UV photo-electron source for the commissioning of the KATRIN experiment

“…The kinetic energy of the decay electrons is analyzed in a tandem of MAC-E filter 1 spectrometers [10][11][12]. The main spectrometer achieves an energy resolution of 0.93 eV at the tritium endpoint of E 0 (T 2 ) = 18,571.8 (12)eV [5,13] by a combination of an electrostatic retarding potential and a magnetic guiding field. Electrons with sufficient kinetic energy pass the retarding potential and are counted at the focal-plane detector, which uses a 148-pixel PIN diode wafer for electron detection (FPD [14]).…”