Open AccessA STUDY OF Λ<sup>0</sup> AND θ<sup>0</sup> PARTICLES PRODUCED IN Pb AND Al
Author(s) -
Min Lyu,
Jen-chi Cheng,
Li Ho-Nian
Publication year - 1959
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.15.230
Subject(s) - physics , parity (physics) , atomic physics , asymmetry , nuclear physics , angular momentum , nuclear reaction , hyperon , nucleon , spin (aerodynamics) , particle physics , quantum mechanics , thermodynamics
Two experiments on V0 particles were carried out with a multiplate cloud chamber during 1955-1957. A total of 550 V0 particles have been found. 67 ∧0 and 44 θ0 particles are classified according the a-∈ method. Of them 58 ∧0 and 38 θ0 were produced in Pb, 9 ∧0 and 6 θ0 were produced in Al. The following results have been obtained: (1) The decay angle in the center of mass system, of ∧0 or θ0 is uniformly distributed. The correlation angle between the production plane and the decay plane is distributed also uniformly. No information can be obtained that the spin of the V0particles are larger than 1/2. (2) No asymmetry of angular dis-tribution is seen thus showing nonconservation of parity for the decays of the ∧0 particles produced in Pb. For ∧0 produced in Al some indication of asymmetry is noted. (3) The hyperon tends to go backward in the associated production process from the consideration of the momentum spectrum, and production angular distribution. (4) The following lifetimes are obtained: τ(Λ0)=(3.39-0.440.63)×10-10 sec,τ(θ0)=(0.86-0.160.26)×10-10 sec. (5) N(∧0):N(θ0)=1.4. (6) The total cross section for strange particle production is estimated to be of the order of 0.8 mb/nucleon, both for Pb and Al. (7) The Pb nucleus is more effective than the Al nucleus for producing a V0 particle, when we consider the percentage of the V0 with respect to the total number of secondary particles.