DOUBLE BETA DECAY OF 100 Mo

Using a liquid argon ionization chamber, the 2νββ decay of 100 Mo was detected with its half- life of (7.5 ± 1.1(stat.) ± 1.5(syst.)) · 10 18 y. The limits on half-lives for the 0ν and 0νχ 0 decays of 100 Mo were estimated as 9.3(5.0) · 10 21 and 4.3(2.7) · 10 20 y respectively at 68 % (90%) C.L. Available world data for the 2νββ decay of 100 Mo lead to the average ®worldvalue of the half-life, T1/2 =( 8.0 ± 0.7) · 10 18 y, which corresponds to the nuclear matrix element, MGT =0 .118 ± 0.005. �·¨ ¨¸¸²¥¤µ¢ ´¨¨ 2νββ-· ¸¶ ¤ 100 Mo ¸ ¶µ³µÐOO ¨µ´¨§ I¨µ´´µ° ± ³¥·O ´ |¨¤±µ³ ·£µ´¥ ¶µ²EI¥´ ¶·¥¤¥² ´ ¶¥·¨µ¤ ¶µ²E· ¸¶ ¤ (7,5 ± 1,1(¸E E.) ± 1,5(¸¨¸E.)) · 10 18 ²¥E. �·¥¤¥²O ¤²O 0ν- ¨ 0νχ 0 -³µ¤O · ¸¶ ¤ 100 Mo µI¥´¥´O ¸µµE¢¥E¸E¢¥´´µ ´ E·µ¢´¥ 9,3(5,0) · 10 21 ¨ 4,3(2,7) · 10 20 ²¥E ¤²O 68 % (90 %) C.L. "µ¸E¨£´EEO¥ ³¨·µ¢O¥ §´ I¥´¨O ¶¥·¨µ¤ ¶µ²E· ¸¶ ¤ 100 Mo ¤²O 2νββ-³µ¤O ¤ OE ¸·¥¤´¥¥ §´ I¥´¨¥ OEµ° ¢¥²¨I¨´O T1/2 =( 8,0 ± 0,7) · 10 18 ²¥E, IEµ ¸µµE¢¥E¸E¢E¥E O¤¥·´µ³E