Higher Precision Measurement of the hfs Interval of Muonium and of the Muon Magnetic Moment

Abstract

New higher precision measurements of the hyperfine Zeeman transitions in the ground state of muonium have been performed with use of the high-stopping-density surface \i + beam at the Clinton P 0 Anderson Meson Physics Facility. The results are Ay = 4 463-302.88(16) kHz (0.036 ppm) and n^/np^ 3.183 3461(11) (0.36 ppm). The current theoretical value of Ay agrees well with experiment within the 0.77-ppm error of Ay t^eor , which is due principally to inaccuracy in evaluation of the nonrecoil radiative correction term. The most precise current value of m n /m e is obtained from our value of \ij\x p ,

High Precision Measurements of the Ground State Hyperfine Structure Interval of Muonium and of the Muon Magnetic Moment

“…A major improvement of this experiment over the earlier work [9] is the use of a resonance line narrowing technique [10]. In the conventional approach, the signal, S, is obtained by counting positrons throughout the beamon time.…”

“…To this end, we combine (9) and (10) with the results of the last precision experiment [9] to obtain Dn͑exp͒ 4 463 302 776͑51͒ Hz ͑11 ppb͒ ,…”

“…The transition frequencies resulting from the fits were then transformed to their values in a magnetic field strength corresponding to a free proton precession frequency of 72.320 000 MHz. The data were taken at 0.8 and 1.5 atm, and so were corrected for a small quadratic pressure shift [9,12] and then extrapolated linearly to zero pressure to obtain Dn and m m ͞m p . The results obtained from each sweeping method were consistent, and were combined to yield our final results n 12 ͑exp͒ 1 897 539 800͑35͒ Hz ͑18 ppb͒ , (7) n 34 ͑exp͒ 2 565 762 965͑43͒ Hz ͑17 ppb͒ , (8) …”

Hard three-loop corrections to hyperfine splitting in positronium and muonium

“…Both experiment and theory have achieved very high accuracy. The experimental errors for HFS in muonium are now in the interval 16-51 Hz [1,2], and a new measurement with the goal to reduce the error to about 10 Hz or to a few parts in 10 9 is now planned at J-PARC [3,4]. Current theoretical uncertainty of HFS in muonium is about 70-100 Hz, see, e.g., reviews in [5][6][7].…”

Muonium hyperfine structure and the decayμ+→e++ν¯Fujii1, Mimura2, Sasaki3 et al. 1994Phys. Rev. D440480View full textAdd to dashboardCite

“…The hyperfine splitting between the spin-0 and spin-1 levels of the muonium ground state has been measured to give a very precise result [15] ∆ν(exp) = 4463302.88(0.16) kHz (0.036ppm).…”