Present status of the fine-structure frequencies of the 23P helium level

Abstract

A new measurement of the fine-structure frequencies of the 23 P level in 4He is presented. The result for the largest interval 23 P0–23 P1 is 29 616 952.7(1.0) kHz, and 2 291 167.7(11.0) kHz for the smallest one, 23 P1–23 P2. Taking into account this new result, an agreement among different experiments at the 1 kHz level is found. Implications of this situation for the determination of the fine-structure constant α are discussed. PACS Nos.: 31.15.Pf, 31.30.Jv, and 32.10.Hq