'tч о/ч /J4 1984" , АУбна. ( 3 Не, t) ОбЪ8АМН8ННЫI. м с с Jl е А.о в а н м й. El INVESTIGATION OF ТНЕ CHARGE-EXCHANGE REACTION

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1 ОбЪ8АМН8ННЫI ИНСТИТУТ RАВРНЫХ с с Jl е А а н й, АУбна 'tч /Ч /J El-8-38 ' IVESTIGATIO OF ТНЕ CHARGE-EXCHAGE REACTIO ( 3 Не, t) АТ 37, 678, AD 78 GeV /с WITH! -ISOBAR EXCITATIO I CARBO Submitte to"pis'ma ZhETF" 98"

,_ VG SMEliseev, VIInozemtsev, APKobushkin? ABKurepin! DKikitin!

S were measure using the ALPHA-spectrometer The same geornetry ("А") was use as in our investigations of(,p) fragmentation / /, In this geometry the ( 3 He,)fragmentation cross sections were also

momentum the strppng cross secton s prac tically inepenent of incient energy This allowe us to normalize our(3he,t) ata at all projectile energies use In the same geometry ("В") we also mae the

2 ,_ VG SMEliseev, VIInozemtsev, APKobushkin? ABKurepin! DKikitin!AAomofilov, MPiskunov, VIShar] ItfSitnik, EAStrokovsky, LStrunov, GGVorooГev, SAZaporozhets, The invariant cross sections of the ( 3 He,t) reaction on С an СН targets at triton enission angles of (} S were measure using the ALPHA-spectrometer The same geornetry ("А") was use as in our investigations of(,p) fragmentation / /, In this geometry the ( 3 He,)fragmentation cross sections were also measure using the same targets At 78 GeV/c the absolute measurements of the ( 3He,)cross sections were mae in the region of P- / 3 Рз using another geometry 3 ("В") In this Не regon of tragment momentum the strppng cross secton s prac tically inepenent of incient energy This allowe us to normalize our(3he,t) ata at all projectile energies use In the same geometry ("В") we also mae the absolute measurements of the ( 3 He,t)cross sections at 678 GeV/c Preliminary results of these measurements are presente elsevher e 5 The comparison of both sets of ata (obtaine in geometr ies "А" an "В") at 678 GeV/c confirms our estimate of normalization uncertainty ($%) of the ata in geornetry "А" The statistical uncertainty of the ( 3 He,t)ata oe s not excee 5% The backgroun contribution is no lar ger than 7% an inepenent of triton momentum uclear Physics Institute, Мoscow Мoscow State University, Kiev Institute for Theoretical Physics, Ukrainian SSR Acaemy of Sciences, Kiev J Institute for uclear Research, USSR Acaemy of Sciences, Мoscow " PLebeev Institute of Physics, USSR Acaemy of Sciences, Нoscov The invariant ( 3 He,t)ifferential cross sections obtaine on proton an С are presente in figsl an versus the energy Q = Т 3 - Tt (Т is kinetic energy) t ran sferre to the tarhe get nucleus The Q resolution was: oq =, 3 an 7 MeV at incient momenta of 37, 678, an 78 GeV/c, respectively А single peak is seen in the p( 3He,t) reaction cross section (figl) The position an with of the peak are close to the expecte ones for p( 3 He,t)L'l reaction The peak shape an location are istorte Ьу the 3 Не formfactor This istortion vanishes with increasing incient mornentum ue to ecreasinf (at fixe Q ) longi tuinal momentum transfer 6 (Q) in the Не rest frame The peak шaxima a re obs erve at GJP) = 98,37, an 35 MeV for inc ient momenta of 37, 678, an I78GeV/c, respecttvely There are two peaks in the C(3He,t) cross sections (fig) The first one is locate at small Q an correspons to spinisospin excita tions of nuclear levels in the resiual nucleus The peak height ecreases with increasing projectile energy,but this ecrease can Ье only in part accounte for increasing uq ]

", - ;t х - t u "'QJ I > >> <9 <9<9 СХ) СХ) (' - _:<>- - - -<>' :%;--- <> -- - _ >f ---- * -) ( J ЩS 8 3 From t he comparison of the ata it follows that: (i) The contribution of the mechanism which

$Q) ::с "" '-' "' '{; - -z - :o_o_"t> -) -u - с) = П E-i 't) С] S * --* Рч з:,_ <>---<>*-- --- - ---- * 'Q:- "3-)' 't) > _ 6 / --, -- * --* '_,-_'" ;--- - - - Q The secon peak is locate in the same Q$ istorte Ьу the contribution from а tail of the first peak But а crue estimation of а possiьle shift in the peak location ( Q ) shows that this shift is negligiьle (5 MeV) even at 37 GeV/c Therefore

istorte Ьу the contribution from а tail of the first peak But а crue estimation of а possiьle shift in the peak location ( Q ) shows that this shift is negligiьle (5 MeV) even at 37 GeV/c Therefore

3 ", - ;t х - t u "'QJ I > >> <9 <9<9 СХ) СХ) (' - _:<> <>' :%;--- <> -- - _ >f ---- * -) ( J ЩS 8 3 From t he comparison of the ata it follows that: (i) The contribution of the mechanism which etermines the -peak ominates the ( 3 Не, cross section for the reaction on nucleus at 6 78 an,73 GeV/c (see fig) (ii) The ratio (R)of the charge-exchange cross se c tion >,-!-) 't) Z:9 С"! Q) ::с "" '-' "' '{; - -z - :o_o_"t> -) -u - с) = П E-i 't) С] S * --* Рч з:,_ <>---<>* * 'Q:- "3-)' 't) > _ 6 / --, -- * --* '_,-_'" ; Q The secon peak is locate in the same Q region as the peak in the р (3 He,t) reaction cross section, so further on we shall refer to it as to the -peak At 37 an 6,78 GeV/c the location, height an with of th -peak may Ье in principle istorte Ьу the contribution from а tail of the first peak But а crue estimation of а possiьle shift in the peak location ( Q ) shows that this shift is negligiьle (5 MeV) even at 37 GeV/c Therefore we neglecte this shift vhen estimating Qbc The QclC) values obtaine are Q (C) = 5:!:_, 75:!:_, an 35:!:_ MeV J' : (' ер (') l t'-(v) <D з= а_м э 'J::,t-, "' (:)/z>9)jw) 'U'PP/9f <] - t ф I > <9 <9 <9 с (' с (' (' % : E-i 7 'k / ' * - f- >- i:lo с :> - [_JЩ S ( :)/7 Л ё> 9)fw] '!5Pr>P/ pp 't) -)-) (l)'lj ;:s 't)--) >- с: Cll ф ' Q u p pfl 75 MeV for carbon an proton increases with increasing incient moment um varying from -5 (Saclay ata 6 at 39 GeV/c) to -6 at 37 GeV/c (the contribution of the tail from the nuclear excitation peak being subtracte) an =3 at 678 an 78 GeV/c (iii) As is seen from f ig 3 an the Q values presen t e above, tlere is а shift between t he - peak positions in the reaction on С an Р at fixe incient energies This shift can Ье unerstoo from kinematics if а group of target-constituent nucleons is assume to participate in the "eler:entary act" of prouction because Р ( Q ) a t fixe Q an incient energy ecreases with increasing tar get mass З: -) Q -=-- / <>-',, /f --- -or-, * <)-,:: :::::, * --""-:::: o r (IJ cl' J> t6 :f ":r -> > г с:) _{j E-i >- 'Рч "' ;:s 't) Т make sure that it is impossiьle to account fo r these facts (see also paper / 5 / ) assuming that the -isobar is prouce on а single "moving target-constituent nucleon, we have calculate the charge- exchange cross sections of the ( 3 He,t) reaction at 6 78 GeV/c Ьу the Glauber-Sitenko r:joel taking longituinal momentum transfer into account The exper imental values of the parameters of the reaction an the 3 Н е form factor we r e use as an input, The oscillator wave function of С an t he shell moel wave function were also use It was foun that the form of the wave function oes not change the results appreciaьly The calculate cross section for the reaction on proton is in accorance with the experimental ata, but the one for the reaction on carbon is in sharp ualitative contraiction with the ata: the ratio R is about 8 insteft of 3; Q C) >Q<t), while in the experiment Q (C) < Q (P) It was f f oun h t at any varaton the nput parameters of the mo el, 3

5 So, the comparison of the ata on absolute (3He,t) cross sections on proton an С, as, well as the Glauber calculation results, show that in the charge-exchange reaction with L prouc tion in nuclei

are grateful to A tbalin, YuVGaponov, VFDmitriev, MIPogoretsky an IPyatov for useful iscussions of the obtaine resul ts, SVDzhmukhaze, ZPHotina an RPetrova f or their help in this work!

5 VG et al JIR, El-83-86, Dubna, 983 б Ellegaar С et al PhysRevLett, 983, 5, pl75; Gaare R Rep on "Delta-ucleus Dynamics" Symposium Argonne, Мау, 983 8 i i i!! "ё!

4 5 So, the comparison of the ata on absolute (3He,t) cross sections on proton an С, as, well as the Glauber calculation results, show that in the charge-exchange reaction with L prouc tion in nuclei at high energies such mechanisms ofthe collective type are essential, which cannot Ье reuce to L -prouction on а single target-constituent nucleon, {) /t / / ' /J J 78 ': "а i ol-' ' J9 t О" ii " We are grateful to A tbalin, YuVGaponov, VFDmitriev, MIPogoretsky an IPyatov for useful iscussions of the obtaine resul ts, SVDzhmukhaze, ZPHotina an RPetrova f or their help in this work!/ REFERECES O't 6 РТЕ, 983,, р33 uclphys, 983, А393, р9; А, р5(е); VG et al Pis'ma ZhETF, 983, 37, pl96 3 VG et al РТЕ, 978,, р63; VG et al YaFiz,, 983, 37, pl3 Anerson L et al PhysRev,, 983, С8, pl 5 VG et al JIR, El-83-86, Dubna, 983 б Ellegaar С et al PhysRevLett, 983, 5, pl75; Gaare R Rep on "Delta-ucleus Dynamics" Symposium Argonne, Мау, i i i!! "ё!) - з - ' O<f,, f 678 i",,, r ' J37 Q OJ Q6 Q, GeV Fig 3 The Q - srectra f tri tons f r om р ( 3 He,t)L (black cir cze s ) an C( 8 He,t){open cir czes ) The proton ata are normazize to the carbon ata at the L - peak maxima within their uncer t ainties, as well as taking fial stat e interaction effects into account, o not provie even а ualitative a greemen t with the ata VG et al VG et al - i' а i "/ l J Receive Ьу PuЬlishing Departme nt on June 5, 98 f, 5

Аблее ВГ Взбуждение и др ре акции перезарядки Вперые при ядрах углерда ( 3 He,t) при,37; 6,78 и,78 ГэВ/с ыских ( 3 He,t) на пртне и с энергиях изерены с рждениен сеч е ния пгрешнсть нрирки % рждение

иссле да ний VG et al Investigation of the Charge-Exchange Reacti on at,37, 678, an 78 GeV/c with -Isobar Excitation in Carbon реакции -из бар Статистическая пгрешнсть 5%, этй El-8-38 -избар Дубна 98

not excee 5%, the norrnalization one is less thar %, These ata lea to the conclusion of а si gnificant role of collective type mechanisrns, which cannot ь е reuce to prouction on а single

5 Аблее ВГ Взбуждение и др ре акции перезарядки Вперые при ядрах углерда ( 3 He,t) при,37; 6,78 и,78 ГэВ/с ыских ( 3 He,t) на пртне и с энергиях изерены с рждениен сеч е ния пгрешнсть нрирки % рждение ы, не реакции с сдящиеся Рабта к избары рждению ыплнена Препринт О бъе д иненн г ее на ядре дн из Лабратрии ыских ин с титута яд е рных Пказан, чт сушестенны е х аниз нуклн лдр а эн е рги й ОИЯИ иссле да ний VG et al Investigation of the Charge-Exchange Reacti on at,37, 678, an 78 GeV/c with -Isobar Excitation in Carbon реакции -из бар Статистическая пгрешнсть 5%, этй El избар Дубна 98 El-8-38 ( 3 He,t) The cross sections of p( 3 He,t)an C( 3 He,t)reactions with excitation in target nuclei have been first rneasure at high projectile energies The statisti cal uncertainty the ata oes not excee 5%, the norrnalization one is less thar %, These ata lea to the conclusion of а si gnificant role of collective type mechanisrns, which cannot ь е reuce to prouction on а single target-constituent nucleon when cornplex nuclei are use as а target, -isobar The investigation has been perforrne at the Labora tory of Hi gh Energies, JIR 8 Preprint of the Joint Institute for uclear Research Dubna 98

IS.Akh«b.ki»n, J.Bartke, V.G.Griihin, M.Kowahki

М^.Ш:й*;п II, 1Д1 Н1Х ЯвШДЮМ* i ПГиГ- ii i) и ii in ill i El-83-670 IS.Akh«b.ki»n, J.Bartke, V.G.Griihin, M.Kowahki SMALL ANGLE CORRELATIONS OF IDENTICAL PARTICLES IN CARBON-CARBON INTERACTIONS AT P *