Radiative Pion Capture in <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mmultiscripts><mrow><mi mathvariant="normal">He</mi></mrow><mprescripts></mprescripts><mrow></mrow><mrow><mn>4</mn></mrow><mrow></mrow><mrow></mrow></mmultiscripts></mrow></math></span>

James A. Bistirlich; Kenneth M. Crowe; Anthony S. L. Parsons; Paul Skarek; Peter Truoel; Carl Werntz

doi:10.1103/PhysRevLett.25.950

Radiative Pion Capture in ${}^{4}{He}$

James A. Bistirlich, Kenneth M. Crowe, Anthony S. L. Parsons, Paul Skarek, Peter Truoel, and Carl Werntz

Phys. Rev. Lett. 25, 950 – Published 5 October 1970

Abstract

The spectrum of high-energy $γ$ rays following the absorption of negative pions in ${}^{4}{He}$ has been investigated. The observed shape of the spectrum and the measured total capture rate [(0.704±0.066) × $10^{15}$ $\sec^{- 1}$ ] agree well with theoretical predictions, assuming that the pions proceed through excitation of states in ${}^{4}H$ with $J^{π} = 2^{-}$ at 3.4, $J^{π} = 1^{-}$ at 5.1, and $J^{π} = 1^{-}$ at 7.4 MeV relative to the ${}^{3}H + n$ threshold, and taking an operator $\approx τ^{(-)} σ e^{i \vec{k} \cdot \vec{r}}$ for the calculation of the nuclear-matrix elements.

Received 24 August 1970

DOI:https://doi.org/10.1103/PhysRevLett.25.950

Authors & Affiliations

James A. Bistirlich, Kenneth M. Crowe, Anthony S. L. Parsons^*, Paul Skarek^†, and Peter Truoel^‡

Lawrence Radiation Laboratory, University of California, Berkeley, California 94720

Carl Werntz^§

California Institute of Technology, Pasadena, California 91109

^*Now at Rutherford High Energy Laboratory, Chilton, Didcot, Berkshire, England.
^†Permanent address: CERN, Geneva, Switzerland.
^‡Present address: Physics Department, University of California, Los Angeles, Calif. 90024.
^§On leave from The Catholic University of America, Washington, D. C. 20017.