Upadhyay, P N

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IACS Institutional Repository

Letters to the EditorI  M i a n  .7. P h y » . 48. 284-285(1974)A preliminary analysis on the (1020) meson*P X. I ’PADUYAY**Ikpnrlmcnl of Ph/z-sirs, Banara'^  Hindu Vnirersitjp Vamua. i^ 221005 (Rvceived 5 March 197J3)All account is prcs(‘iit(*(l of a missing mass count(m* rxpo?‘ini(uit pcrformod to study th(‘ production and tlu^  d<*cay ol tho (j) meson prodmtxl in integration7T p (p)tat the l)(‘am inonuuita near its ^woduction tluesjiold.The niissiiijr mass of the ^ meson was calculat<‘d hy measuring t]u‘ incident pion momentum and Die nucleon time-oi-flight. A hoani ot pion was trans­ported l)y a cpiadrupoh^s and dipoles to a litpiid hydrogen targ<d wliich was 20.4 cm long and fl cm in diameter. Tlu^  neutrons were didcctod by a ring of six identical scintillation counters pla(!od ti.lo meter downstream of the target. Tiie time-of-flight and lumce its four-momentum transfiw, / was measun^d by mi^asuring the neutron time-of-fliglit l)etw(Mm a timing (M)unter placed just up- stn a^m of the liydrogim targ<?t and the counters tiine-of-flight zeroreference calli^ d the fast }>eak was obtained by the b(‘.am pions scattered througli small anglc‘^ in the target. T.lu‘ number of chargtxl particles and tiie gamma-rays in tJie final state was determined by an array ot counters whicji surrounded the target. The apparatus and method of operation hav(^  betai described by Binnie et al (1971).1’he number of neutron (*v(mts p»*odiic(Hl for a fixi^ d number of pion in a specified time-of-fliglit region caliiMl gat<^  is said to bi^  yi<*ld. 4\he curves obtained by plotting the yield in a gale as a fumflion of tlu‘ incident pion momentum is calUxl the yield curve, dust near tju‘ produiddoii t jireshold, neuirons go forw^ ard in a narrow' Honca*,, the neutrons we.n^  detected al laboi'atory angh^  nmir2.S'. [n ord(U‘ to achieve a good mass resolution and maximum collection effi­ciency of the apparatus w.hieli weie only olitaiuabJt  ^ at tlu^  incident beam momen­tum just near the production threshold, a gat(^  of 14 to 17 nsec, after tJio fast-peak corresponding to 0.18 -  ^|/| ^  0.22 (0eV/c)2 was considered.The yield curve (without any decay mode selection) has incidated an en­hancement near mass 1020 MeA7c‘^  wjiich is identified as the 0 meson (figure 1).• Work done at the liuthorford Laboratory, (^ hiltrm. Didcot, Hi^ rkshiro, IT.K,♦♦ present address : Gaya (^ olleg(s Gaya, Bihar.284Ancdysis on the ^  (1020) meson 285Tho ostiniatod jiiaas of th<^  <j) moHon in in good agreomfvnl witji provn'ons oxp(M*i- montH (B(»rtanza el al 1902, Bollini et al 1909, Hyams ^ a! 1970). An on- hancomont in tht^  ^-~>;r‘7r 7r° docay mode \\as also ohsorved in tlio yiold cairvo of tlio some gate (figiiro 2). No onlianooinont for ih(^  (^vonts in this massrogion was ohsc r^vod.4 4 0tv . I.2oO 40 0>  360tel3200 I8 6 l t l$ 0  22 (6«V/c)NO DECAY SELECTION ^  (1020 M«V)III II I  I/' ' i i i i i i1940 I960 1620 1660INCIDENT f>ION MOMENTUM IN M«V/cThe yield curve of the uentron events in the oaft* 14 to 14 iis(‘e. iiftiM* the fast-peak.oa.•o400 I8 £  m $ 0  22 { OtV/c)i j i i rJFiK.1540 (980 1620 1660INCIDENT PION MOMENTUM IN M»V/cThe yield curve of th(' tt'tt yy events in tlu‘ Rftte 14 to 17 nsec, after the fast-peak.The (j) meson is widl ostahlisjiod. Its (juantiim niimhers w(mv determinod idt '^pondontJy (Connolly e/ a] 1903, Sohltdn et al 1903). 33ie prominent d(H*ay modes of tlio meson wen  ^ found to he and K K hut not /v/7v',/\ Tlie(/>-¥ d<HUiy mode allows odd spin (./), negative parity (P) and negatives’^-parity and its f^parity i>s odd. Abstmet  ^ of an onliancemoiit in tt' tt doi^ay mml(‘ iji (/) rtJgion agrees u itli its C-parity assignment.RrferknoesBortanza L. et al 1962 Phys. Pev. Ijett. 9, 180. Biniiie D, M. et al 1971 Phya. Lett, 36B, 257. BdUini D. et al 1969 N u . Cem, 60, 541.Cninoliy P. L. et al 1963, Phya, Rev, Ijett, 10. 371. Hyam« B. D. et al 1970, N ucl, Phya, 22, 189. Hchlein ? . et al 1963, Phya, Rev, Lett, 10, 368,

A Preliminary Analysis on the ∅ (1020) Meson

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A Preliminary Analysis on the ∅ (1020) Meson

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