NDLI: Two-photon spectroscopy of antiprotonic helium

Content Provider	Springer Nature Link
Author	Barna, Dániel
Copyright Year	2014
Abstract	The precision of laser spectroscopy of antiprotonic helium (a helium atom with one of its electrons replaced by an antiproton) has improved by almost 4 orders of magnitude over its 20 years of history. Experimental transition frequencies can be compared to 3-body QED calculations to derive the antiproton-electron mass ratio. In the latest measurements of the Asacusa experiment at CERN, two-photon transitions of antiprotonic helium were excited using two counter-propagating laser beams. This method reduces the Doppler-broadening caused by the thermal motion of the atoms, and allowed us to measure the transition frequencies with a fractional precision of 2.5–5 parts in 109. From these frequencies, we derived an antiproton-electron mass ratio of 1836.1526736(23). Our precision approaches that of the experimental value of the proton-electron mass ratio, and agrees with the latter within errors. Assuming CPT symmetry (i.e. $m_{p}=m_{\overline {p}}$ ), we further derived the electron’s atomic mass as m e = 0.0005485799091(7)u from the more accurately known atomic mass of the proton.
Starting Page	89
Ending Page	95
Page Count	7
File Format	PDF
ISSN	03043843
Journal	Hyperfine Interactions
Volume Number	229
Issue Number	1-3
e-ISSN	15729540
Language	English
Publisher	Springer International Publishing
Publisher Date	2014-04-29
Publisher Place	Cham
Access Restriction	Subscribed
Subject Keyword	Antiprotonic helium Antiproton-electron mass ratio Nuclear Physics, Heavy Ions, Hadrons Atomic, Molecular, Optical and Plasma Physics Condensed Matter Physics Surfaces and Interfaces, Thin Films
Content Type	Text
Resource Type	Article
Subject	Nuclear and High Energy Physics Atomic and Molecular Physics, and Optics Physical and Theoretical Chemistry Condensed Matter Physics

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