Alpha and helion particle charge radius difference determined from quantum-degenerate helium.

Λεπτομέρειες βιβλιογραφικής εγγραφής
Τίτλος:	Alpha and helion particle charge radius difference determined from quantum-degenerate helium.
Συγγραφείς:	van der Werf, Y., Steinebach, K., Jannin, R., Bethlem, H. L., Eikema, K. S. E.
Πηγή:	Science; 5/22/2025, Vol. 388 Issue 6749, p850-853, 4p
Θεματικοί όροι:	Alpha rays, Helium, Quantum theory, Standard model (Nuclear physics), Physical constants, Spectrum analysis
Περίληψη:	Accurate spectroscopic measurements of calculable systems provide a powerful method for testing the Standard Model and extracting fundamental constants. Recently, spectroscopic measurements of finite nuclear size effects in normal and muonic hydrogen resulted in unexpectedly large adjustments of the proton charge radius and the Rydberg constant. We measured the 2³S→2¹S transition frequency in a Fermi gas of ³He with an order of magnitude higher accuracy than determined previously. Together with a previous measurement in a ⁴He Bose-Einstein condensate, a squared charge radius difference rh² – rα² = 1.0757(12)exp(9)theo fm² was determined between the helion and alpha particle. This measurement provides a stringent benchmark for nuclear structure calculations. Editor's summary: Precise measurements of the charge radius of light atomic nuclei can be used to advance the theory of atomic energy levels and to improve our understanding of the nuclei themselves. One way to measure this radius is through precision spectroscopy. Two groups have now measured the charge radius of the helium-3 nucleus, the so-called "helion." Schuhmann et al. performed spectroscopy of muonic helium-3 ions, in which a muon replaces the electron orbiting the nucleus, and van der Werf et al. worked with the usual electronic helium-3. Both groups improved on the precision of earlier results. —Jelena Stajic [ABSTRACT FROM AUTHOR]
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Βάση Δεδομένων:	Complementary Index

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