| 释义 |
pi-meson Nuclear Physics.|ˌpaɪˈmiːzɒn, -ˈmɛzɒn|
Also pi meson, pimeson.
[f. pi n. + meson3.]
The original name for the pion. (Freq. written π-meson.)
[1947Lattes, Occhialini, & Powell in Nature 4 Oct. 455/1 It is convenient to refer to this process..as the µ-decay. We represent the primary mesons by the symbol π, and the secondary by µ. ] Ibid. 456/1 The restricted range of the π-mesons in the emulsion.1950D. Halliday Introd. Nucl. Physics xii. 455 When negative pi-mesons are absorbed in matter,..there is a major nuclear disruption. 1953Jrnl. Brit. Interplanetary Soc. XII. 203 The neutral pi-meson dissociates almost immediately into two high energy gamma rays (photons), which inititate the photon-electron cascades that are frequently observed in cosmic ray processes. 1968Times 19 Jan. 13/8 The object..is to see how frequently an electron and a positive electron (or positron) would be converted..into the radio-actively unstable particles of matter called pimesons (or pions). 1972Daily Colonist (Victoria, B.C.) 3 Mar. 16/8 The new technique involves a radioactive beam of sub-atomic particles called pimesons. 1978Sci. Amer. Mar. 57/1 The mass of the muon (106 MeV) is quite close to the mass of the pi meson, or pion (140 MeV).
Hence pi-ˈmesic, -meˈsonic adjs. = pionic a.
1952Physical Rev. LXXXVIII. 134/1 We have found direct evidence for π-mesic atom formation with the nuclei of carbon, oxygen, and beryllium. 1953Ibid. XCII. 789/2 Experimental studies of π-mesonic x-rays in light elements have been made. 1954Ibid. XCVI. 774 (heading) Energy level displacements in pi-mesonic atoms. 1970Lock & Measday Intermediate Energy Nucl. Physics xi. 276 Because of the mass of the π- (139·6 MeV) is greater than that of the µ- (105·7 MeV), the energies of the pi-mesonic x-rays are about 30% higher than those of the equivalent mu-mesic x-rays. |