Measurement of the induced pseudoscalar form factor in the capture of polarized muons by Si nuclei

• Published in: Nuclear physics. A 1995-05, Vol.587 (4), p.577-595
• Main Authors: Brudanin, V, Egorov, V, Filipova, T, Kachalkin, A, Kovalenko, V, Salamatin, A, Shitov, Yu, Štekl, I, Vassiliev, S, Vorobel, V, Vylov, Ts, Yutlandov, I, Zaparov, Sh, Deutsch, J, Prieels, R, Grenacs, L, Rak, J, Briançon, Ch
• Format: Article
• Language: English
• Subjects: 28Al deduced levels, Natural target; deduced nuclear state alignment; measured Eγ, Iγ; Nuclear Experiment; NUCLEAR REACTIONS 28Si(polarized μ−, ν); parameter [formula omitted]; Physics
• ISSN: 0375-9474; 1873-1554
• DOI: 10.1016/0375-9474(95)00052-3

The observation with high-resolution Ge detectors of the 1229 and 2171 keV gamma-rays emitted after the 28Si(μ, ν) 28Al(1 +, 2202 keV) reaction allowed us to determine the nuclear-amplitude ratio x ≡ M(2) M(−1) characteristic of this muon-capture reaction. Using the nuclear-structure dependent evaluation of various correction terms (model of Ciechanowicz), our result x = +0.254±0.034 provides for the induced pseudoscalar coupling g p the ratio g p g a (0.848m μ 2) = 3.4 ± 1.0 , to be compared to the PCAC prediction of g p g a = 7 . The model dependence of this apparent quenching remains to be assessed.