Eberhard, Phillippe

Kalbfleisch, George R.

Lannutti, Joseph E.

Lynch, Gerald R.

Maglic, Bogdan C.

Shafer, Janice B.

Stevenson, M. Lynn

Xuong, Nguyen-Huu

eScholarship - University of California

Lawrence Berkeley National LaboratoryRecent WorkTitleTWO-MESON ANNIHILATIONS OF 1.61 - BeV/c ANIT-PROTONS IN HYDROGENPermalinkhttps://escholarship.org/uc/item/2tq4h4dgAuthorsLynch, Gerald R.Eberhard, PhillippeKalbfleisch, George R.et al.Publication Date1963-01-17eScholarship.org Powered by the California Digital LibraryUniversity of CaliforniaI '< UCRL-10633 · University of California Ernest 0. Radiation lawrence Laboratory TWO-MESON ANNIHILATIONS OF 1.61-BeV/c ANTIPROTONS IN HYDROGEN TWO-WEEK LOAN COPY This is a library Circulating Cop~ which rna~ be borrowed for two weeks. For a personal retention copy, call Tech. Info. Dioision, Ext. 5545 Berkeley, California \ DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or the Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof or the Regents of the University of California. :q - I. :J-C ·':.:1 -• w ~ - . ~s I I . 'T' I . I~ ., l ' 1 - I . •. L ~ ..., J~ • - e . L a r G•• ral c J sep 1 'I· rald R. Lynch, Phil'ppe Eberhc::.;.rd, osep F . L nnutti, Bogdan '"' . a 1.:Ji ·, M . Lynn Stevenso. , and g· ye - '- u Y o Lawrence Radiation La oratory University of C llf rni . Berkel y, Cal'forria J ary 17, 963 A ST R A ~T R--.. I!!'· s ~ '• S L fer, R P:roton-antiprot n a.nni~ilati.ons at l.t 1 Be /c wit only tw mes e the final state ave be exatnined in the 72 - inch • ble c n. r. cr ss sections mea~H1red are .J.. p + p - 1T + 1T • 11 9 ± 30 fJ.b p + p - K- + K-t 55±18 fJ.b. - - - + Th- K dis ribution in p + p - K + K is peaked s rougly fo ar th ll K- mes na prod• ced i the forwa_ ~m t tenth o · t._e ~t"'" s Th. 1T - event show no such effect , with o 1 · 2 of t in the same forward interval. Care£ 1 study of p rJsi le c !lt events indicates hat lmost all of them are e uine t :.ro - ~~e TWO--1-so ~ 1 . .. 1- .Je I .... eral R. Lynch , Ph11" ppe serh F . Lann o dan Lyn St venae. , L~ trer ce R.-' Un. vers1t b erkele J a r 1 , 19t 3 "''I IPR ucl on- antil \lCleoQ. an ih:lati n into tw -1 ee c inc r e a in in port nee : i ,b- 1 orgy l' ysic . ' r t "' - m:;..t r x t 1 se r actx ns may b come irn rtant b cause they ar~ scr ed b ·a t u t ,f t S· s t cescribe t e •· c • scatterin~ . In ad · f the relative t No - m s n - nnihil tio cross £ecti ns t lar ~e momentum tr nsfer . and the Ge 11- ann -T ... rt'cula -, t mo ·1 'If ?+. - + k 1 e1 n model pr · cts t s -+00 a~- -p- n-+ + tt ., = a-+p- Ko + - o . 10 experi ental measure nents oft vo - m .son r eported, tl f1r st f0r 1. ; 1- eV/c ant' pr .tons 2 ... n e e rest. 3 "m re co lcte report f th annil il t'on de nta1ns am3re c rc.ful ay is f t di the p r ·Hnunary report. 4 · per , and b"'t ;vc the tw ro anti proton an ihilati n s a 1. 1 e V / c ~ :t .. e ted. r e e cond f r V 1c s s be-rn u. pu' hs t-1 f rtw - n.e or.1. -:. ut 2 00 p·o iJ c rg P3.rticl s ;.! h.es o-pron -2-...:: i 1 i - 1,. J,(' th ba t 20 , 2u ) 1eae 23,00 .. ~nter l tc.:.~e . ve fo d n· ~ :firat oc f t f' l •. .!.. o L.e .sc · 1 in~ t ~ble and, 1f nee s 1'}'• !:' 1l y •• eao :.e t n c cq::Lan. ~nd ed. t v c - t re e t e h... a p- c1 ... ·on n oubt dly · .er not two -. T ;. • r < ce. u r~ eli!. a out 12. f and an-lyze n ·he trac - ec l <. ru~..:t 01 • roRran: P ·-I a d t .:rt b-am, nd fey we :re el·_ ·n:lt fr .m · 1 s m t ·· . ,f incld"'~-t p1 1 • ..e fit. cl t n 9 fltt d el Bti . SC::l t rn -f of dy a ... i 1ilatio r ... ess ~e . (.1 ... I. I r.- r.0 r G 1l j : ':/ -t -, - :J r cees s . l s s !! i !' t e ~ s' ~ f p T , o .. se ..11 J £ t e 93 v:.n B t. '11.( s n 2 c y· in • .J.u.c t r ~"lm n '"' is "'" T - K' 2 atte:rin c .. .,. . . <lf • fe~:r T u n· f ur r ol ( ev l.''J' f f e -~-ve a t 0 •· t l' al . ., s z nti ' f>S(' y 1. e e ··z 1nc . eu::a that r- -1· - ·a t tr it 2 I < 3 . T re tlau 10 'f r "' 2 l' :r ood ~ J~ e 'l' 9 s n·· I y st s l"eme r • :rt 1.~n y o! a, t u I Sl ' f t ;:-n r- .s.:; ( . ' s t v. ie s £, r f e ' ~~ .. 't' b . L • ble r . t f s ·ve t s a. ·ve t . ev ~ . t l ""e .. ~· -. s £ I 2 ( - 1 . ' -c nd" eo a.n - 4-· .e of r e o s great r a.n ::,~ ). ..., t all the K+ - candidates f ... l-. -1l1!1T , In --3 res ~ t 11 t. .se c , , -11'0 £its better • n ny ot; er thr e -b dr final ,s·~at . b f ct, £ r nl l f t.u~ 11 events that f1t .K+K- is the probabUity aseoc1. t -·d ith tne x better fort \e K' ·-than forth n+n - n° interpretat'Ol. Nevf:rt le E::S , w bel' eve that early all t eae eve s are t:r ~ eve .. rs . · !he first pieces of vid nee t thi effect are t ? X · strib!.l · tbemselv s . It would be expected t at if these ev ts ~J re m· ::;i lt rp!'e z eyents, t ex "str buti01 volll fvr. a flc;.t continmrn rate t- for t observed pealun. near zero . This pea dng, on th~ ot er nd, s ~x e .ted from true two - bod events . One rnight ,..ect by oint'nr. o• Glc..t"> l as already been dy -~eots .vhlc de at the t:H.:a.11ni t ble and, t _ref .. :e. l/OUl. contrib ..e lar, l b.en li X n 2 > 100 -h t' .. t t nni -ta le 'I sc of t e event tad 1·e. t i':tive s ou dre f: r t\e bj~:.cti to h .... more irect chec. of ss bl. sea nin -ta le . i s a J.inA h1 m. ie when a lar(l'e ra.1db1n sa. ple of two - p ·ong eve ts were me-G re . v measul:'ed in luJed a 1 iM::lastlc two - pr n event from · c . ant'proton inte:!'actio s - -a sampl. ne rly 011 -} ·1! •s 1· r ge aa t · e + -In this aample w re f und 9 'fl 11 ev""nts and K even to ee , seveu of tne 1T + n- event + -a. d all the K K eve. ts h d ee. f • 0 e of the new vents had been missed in t 1 first sc<L:. £ e iiL l, a t d been missed :in tl-.e sear~,;h for two-m"'aon arm' ilat· na . 1 ex 2 d" Ar· foT t ese eve ts 1.8 s, o ... 1 it. F~ . 2. These r1but o _s indic t · t X f th b ck ro 1 eve 1ta t. On t .'l.e as . s f. -. -l t t~e · n .. .r. :: :.. f. · r t c tiproto nnih1l :io s ' s aim 1 te t e sane d + - .-ly g :ilyGt ~ t t a z e th·' rc is a i . rly 00 epre i aty-l~ t 8 nul ted s e s 10 rn on ., . ' · vent · 1ndica ted b y h~ a: d..-.::-:. stent .vit t t nu dat . Fu:rt·e tnorti , t'.:: ~_·g ... • Udi d ' atri 2 f rl; fl ..... a. ,J t 1a• t 1 .-:te · !', .~ .,·t .. 1.. < 30 . It st1ll "i r-.a · h.i L b e pla'n • -OS f i: :1e • t -n- ;; 0 inter re at:on b <:tt r t incmatic~ r e ::: c 1 tL t a \.. l' - ""ve•. ~- n b e - • e .tc .. _ -f• l·,. f t · · 1- sa_ .... q - f' ,r .... , ,.+ -o .1 1:1 l e . n ~ .J_ ..- .~ -r. ~ • b tt r t t n t 1· , " t. d t t. 1 :r: a er r o r s u.l t e 'Oted _ ::r u ur C'%G -.1 kn , t a t t .e q ;:::r~ nd n · t r FA _- r \ n was I 7. ~ h c \ t e err rs - t i n e qu te rrore . 2 v for t le ,. - (more ne .. rly L a :r lt c ' h. t l ,. 1T 1! 2 V L 0 £ . l ev . ~1ts: ·f t a ~d , o r :1. ed av b .i i ' t ·~·-, . '17 r ·6 -•t -r. orrec n fo r :f"cienc'csa d akin p o on cro~w sec i n, "' und t e f li ln res tlon~ t l. 1 a.n (2. 3 a- + = 119 o ~J.b +p - 1T + 1T a-+ K + K- .:: 5 . ± 18 t b . p p -+ + + -The fraction of a. .i ilatio .. e proceeding by the 1T 1T an - 3 - ~ 0. ) 10 ..lnd (1.1 :.t:-0.4) 1(, , respectiv .ly. s " -1 3 1 frequency · e 0 . .... ± 0 . 15 ti:rne grea as \: fr que cy obacrv. d i r · s ·at rest , and t~ two - a ~ a.nni il io. fre . uenc is , (' rres p n y , . .J . 3 time as gre t. Inth"'pr vio esearchfor -+p - 75.-t.l\ ven·s, vents ith fH' c ted d cays- er examined. ~o e oft cu . .,, r two a so · ated ne tral decays fit e he react" on p + p- T 0 ·0 wi 1 a ingle a$s ciat d d c y did fit t · r~ac~: well , nd anot e oorly. 1 e e even c uld b bc:r.ck:_ r;) 1nd ve ts . !Ce e rob ab· 't '-'/9 . w ca ~·y·>'itl tl st ::onfide~ ce th cr 9 seCt.!.O for 1:" + p - X0 t T. e enter - of- rna an ular n t e - fr two - body ann~ ·tat o are sh .rn or _;_;-i • 4. Th. dis ributio a pl tt ci ay t at one can compare the different· al r s s ~ction" oft. t ;v t t e an. momentum tran £ r . t t · en r .y and es o .e t pr di,...tion o£ . Sakata odel that t e n 11 nd the K cr so e al is not ;rell s t sfie . T' e str1 n £ea.u;r. ..}{ t 1ese d' stributi • o is th ... t th .. a f 1. to al eohd an l . T ta t a ~fft::ct is t t .;; 11 ev ~ts , C Jl!ll"C C d n ·t · ve 3 tr n :. ~r stmplest E:l-tc L .:rr ~0 • n e :nodel i~Gt rn -lo " st - c•r er d' a r'"'mEJ :r sul i fi ct . ••• 3. rutu to large. n ·ed' t .?.t for · th . r r>arity ,.--£ 'lir-- Z . calc lat f ts ~h K. I p .... ri y but L. t f r d '£A 1 ar'ty. C-O s se ti-t 13.'~ 7 V':<C 'l. .at We 1 oi". .:\ nk _ rofe8 sor uui ' · .uvar~z f r u., c L ·a Ya, r ~ ·d , rl R; a pp rt 'n t>us . e a o e :rc f. t .e: eve1.ts j s n~uc~ _pre · ted. r s~ P;r p ys . ,... .• . .:. 2. !. ;.·ald. yne l, . " .. .)~ , ! ) . 3. :,; 1 0 n , l ~r • . P . re ry, P . P.:v .. ::; ~l ·z , • t * :J.l J - c~ • 1 /. l), . 3: l. 4. . R . _ y~.cn , R. E . , R . r .:o.l~fl. sc i e I "S tev ~n 0 pa - 10' - £. ? . B. ,. · nd , 19 ~- · ~v . om_ , t not ·tl, ~f t is f ee_. rr ted l re r; -:r :n :: .e 72-. ch b 7. lC! 1 8 s p cv'ch, N d c }."' 1 ctl (T .si ). ar e 2_ ., . . 1 .,i f 1- 2 d" . t-'t' ~ 1 "" • . • stograms o t ,,te X ut .. ·l..,u l n .LOr t e Be e ter.:. sa le f vent - + for t e hypothese s of p + p .- -r n and p events occur on bot plo T 1e cr as- ~ 1<6 q ar s r pt· t a t have a smaller 2 l! :r the t l.er o - 1e r~..:ta io . Fi 2 . istograms of the 2 dis r'buti f~)r t.:.e . X 1T 'I for events fro n the r ndo o mple oft .,_,c ro. ac ve t 1 only once. F' . 3. Histo Tam f t e X 2 distribution f >r the n n t .e simulated events . E· ch event ·a plotte Fi . 4 . !l'l$ o£ the distribation oft e c . .. .n le f r t e evet s t at f. + -1T 1T and t - hypot :1e ea. 1 he i tri' uti n a e plot e m ilCl t. at one can di:rectly comp!lre the differen~ial cro s cti na 0 ;;. <.~. f of momentum trans£ r. 1 I I. I I I I I l l' j . I · ../ -10-UCRL.,.l0633 <j" r--------------------~----------------------~0 00 0 0'\ I ::::c:::: · + + ::::c:::: t a.. + ta.. -~------~ I - 1::: { t a.. + 10. N I ::J 0 :2: ()) 0 (X) 0 1'-(\j X ....... b!) ...... · ~ l I i I I 1 1 I . ! I ! I I I I ! I II I .. I I! I I I l I I ~ + ~ (\J >< -11-0 0 l() 0 0 ~ 0 0 r0 0 0 N 0 0 s~uaAa :JO JaqwnN I ~ + (II • i== >< ' - ----.... ~ - --- .--- ---- · - ·~-....-.... ; - - ---- - ----- --~ --,. --·-UCRL-10633 -o 1.{) -o-N ::l ~ N . b.O ..... ~ 8 6 4 en +- 2 c: OJ > Q) lo-0.> ...c E :::'1 z 0 4 2 0 -12- UCRL-106.33 I I I I I I I I I r- -Cos 8 p 7T -.__ -r- -l -l f- -I I I I I I I 1.0 0.6 0.2 0 -0.2 -0.6 -1.0 I I I 0.4 o.s 1.2 1.6 2.0 2.4 Invariant momentum transfer 2.8 3.2 ( BeV )2 r I i Fig. 4 MU-29144 UCRL-10633 · -13-0 0 II") II") L() -0. I N I ::::> ~ ·j ! • : ,, .· . 0 0 II ~ II II . I I I 0 i I 0 I f'() I I t:::: ('() ~ + . on + ~ t:::: .... ~ ~ (\! >< I >< 0 0 I N :1 1 0 0 I (\J 0 s ~uaAa JO JaqwnN ! l J. I ~ .. I IIIII 

English

TWO-MESON ANNIHILATIONS OF 1.61 - BeV/c ANIT-PROTONS IN HYDROGEN

TWO-MESON ANNIHILATIONS OF 1.61 - BeV/c ANIT-PROTONS IN HYDROGEN

Abstract

Similar works

Full text

Available Versions

eScholarship - University of California