The masses of positive K-particles

Abstract

o f. c a l i f o d a Berkeley, Californid ' October &4, 1955" Our program of measuring meson masses' has bean extended t o the positive % Kp2r $ 2~ K p p and 7' p a r t i c l e s w With the Bevatron a s a sourae, and employing a modification of the Kerth-Gtork quadrupole lens and analylilng-magneb arrangement, we have obtained a mass resolution of lo@ f o r an individual particle.. Using the stopping behavior o r the grain densify of t h e seoondary for K-particle alassifioation, and the multiple s c a t t e r i n g as a oheck# we obtained p r a c t i c a l l y pure samples of the txbove types of # mesons f o r ana1ysf.s. The p a r t i c l e s were oolnpared d i r e o t l y with protons of the same momentum, and a l s o with the 7' meson, the mass of whioh i s known n~o. m t e $~. ReLeLa-tive t o t h e mean 7 mass of 966 we obtain the following results, a l l i n eleotron .mas8