A. TILQUIN C.E.R.N., Geneva, Switzerland

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401 'I' 'I' PRODUCTION AND LIMITS ON BEAUTY MESON PRODUCTION FROM 4 0 0 GeV/c PROTONS. A. TILQUIN C.E.R.N., Genev, Switzerlnd A BSTRACT.

1 401 'I' 'I' PRODUCTION AND LIMITS ON BEAUTY MESON PRODUCTION FROM GeV/c PROTONS. A. TILQUIN C.E.R.N., Genev, Switzerlnd A BSTRACT. F rom study of multimuon events obtined in high luminosity proton-pltinum experiment t 400 GeV / c, we find 15 ': 4 ljjljj events, which correspond to production cross section ( ljjljj ) 7 ': 10 picobrns. The observed production is compred to the events previously found in the sme pprtus from incom ing QCD predictions is performed, giving good greement TI comprison with w ith expecttions from gluon-gluon fusion. F injjy, using like-sign dimuon, trimuon nd qudrimuon events, we give model-dependent upper lim its on beuty meson production : centrl models, 0 nb/ nucleon for diffrcti ve production. nnobrns/nucleon for

2 40 l. I N TR OD UCTION. I n previous publictions [ l, m ultimuon events produced in ], the NA3 collbortion hs given results on 11- nucleus collisions, from to 80 GeV / c. These events llowed, in conj unction with like-sign high mss dimuons, to set model-dependent upper l i m it s (of the order of to 1 0 nnobrns) on the production of beuty mesons from 80 GeV/c 1T mesons []. From qudrimuon events, evidence ws given for the s i m ultneous production of two J/lji mesons with cross-section round 30 picobrns per nucleon. This ljilji production hs been subsequently explined by severl uthors [ 3, 4-] i n t h e frmework of perturbtive Q C D, t h e production f r o m by qurk-ntiqurk grphs. In the present tlk we give results on from proton-nucleus interctions t 4-00 GeV I c.. ljilji 11 mesons being dominted production, nd on multimuon events THE E X P E R I M E N T A L SETU P. T h e N A 3 exper imentl set-up [ 5 ] w s dequtely modif ied t o tke dt with n 9 intensity round l G e VI c protons per second ; i n prticulr t h e hdron f i lter ws incresed to 3. m m order to hve hdronic punch-through nd neutron bckground comprble to tht obtined i n previous dt with much lower intensity. The trigger required t lest on muon with P (verticl component of the trnsverse Tv momentum) greter thn 1 GeV I c both in the upper prt nd i n the down prt of the pprtus. A complete description of other modif ictions with respect to the previous set-up my be found in ref. [6]. 3. SELECTION OF E V E N TS. We hve followed t h e sme nlysis procedure s lredy described f o r the selection i n ref. [ l] : - Only muons with good time signture (within ': 4- ns with respect to the bsolute timing of the event, s described in detil i n ref. [ 1]) re kept. - A multitrck vertex f i nding procedure i s performed i n order to ssign events either to the P 1t inum trget, or to the bem dump. Only events ssigned to the P 1tinum trget re considered i n the follow ing. - W e sk tht the trigger requirements be fulfil led by one 4-. '!' '!' E V E N TS. - combintion. F ig. l gives the distribution of the two mss combintions, m nd m, for ) 1 qud r i muon events with (--) topolog y. The ljilji signl is present ; it is evluted from I (m -m )' ( m -m ) '. 1 lji lji 0. 5 GeV/ c ', w e f i nd 1 cndidtes F ig. l b where the events re plotted with respect to d cndidtes being defined by t h e condition d including events from the bckground. <

3 403 Other bckgrounds must be substrcted from these cndidtes - Due to the very high bem intensity nd interction rte, the pile-up of two J/ ljj issued from two different interctions within the 8 ns time window is not negligible nd gives ( 4 ) ljjljj events. - R e interction of secondry hdrons in the pltinum trget gives negligible bckground ( < events expected). Thus, substrcting these 6 4 bckground events from the 1 obtin 1 5 4\jJ\jJ events in this smple of dt. cndidtes, we b) K inemticl properties of the events nd ljjljj production mechnism I n order to determine the cceptnce of the pprtus, we hve used the explicit prmetriztions of the ljjljj production cross-section given in ref. [3] nd [4] for vrious production mechnisms : qurk-ntiqurk fusion, gluon-gluon fusion, diffrctive nd centrl production with intermedite B-meson sttes. The cceptnce i s equl to : %, nd gives the following ljjljj production cross-section : \ \j!\j! ) 7 I 0 picobrns/ nucleon This result is i n very good greement with the prediction obtined from ref. [3] using gluon fusion giving t Is ljjljj events in p-p interctions : ( ljjljj ) 30 picobrns 8 GeV. Therefore, s expected, the present results re comptible with production vi gluon fusion, w heres 11 -induced events were comptible with qq fusion predicion. The mesured cross-section is displyed on Fig. d, where the totl predicted c r o s s - s e c t i o n hs b e e n s c l e d by f c t o r T h i s f c t or [3] ccount s f o r next-to-leding Q C D corrections ( like t h e K -fctor in Drell-Y n) nd f o r J/ ljj production through sttes. c) Esti mtion of the effective trnsverse momentum events : of prtons from ljjljj It hs been proposed [8] to use the trnsverse ngulr correltion between the two \jj' s of ljjljj intercting prtons event, to estimte the "effect ive" trnsverse momentum of the <K <K > where K < KT > T > eff T prtons QCD' T prtons of the prtons, nd K concerns the primordil P T coming from the next-to-leding QCD corrections. QCD ccounts for the effects

4 404 The experi m entl vlue obtined fter bckground substrction «l» ( 1 3 ": I 0) 0.7 ": 0. GeV l e, nd is i n good greement with tht obtined k < T> eff induced i)!i)! events of DD pirs. degrees gives f rom UPPER L I M I TS ON BE A U TY MESON P R ODUCTION. ) The events. the T Beuty mesons hve been discovered nd studied in e e - nnihi ltions round ( l 057 5) resonnce. They remin to be detected in hdronic interctions. I n 4s p r e v i o u s pper [ ] we hve g i v e n m o d e l - d e p e n d n t upper l i m i t s ( f r o m to J O nnobrnsl nucleon) o n beuty production from 80 GeV I c pions. The present 400 GeVlc proton interctions re nlyzed i n the sme wy. F ive ( i)!i)! events re excluded). All different f i nl sttes re considered : like-sign dimuons, trimuons events with or without one J / i)!, qudrimuons events with or without one J/i)! selected events must come from the P ltinum trget, nd ll muons in the event must hve good t i m i ng signture. Other cuts re performed, in prticulr on trnsverse momentum of individul muons or of muon pirs. These cuts re sum mrized i n Tble I ; their vlues hve been choosen from sim ulted events to enrich the smples in B meson cndidtes. b) Acceptnce. We hve generted B meson pirs ccording to the models described in refs. [3 nd 4]. The momentum distributions of the decy products of B mesons ( m uons nd D mesons) hve been tken from Cornell results [9], s well s the most recent vlues of the B meson brnch ing rtios : µ X) ( ": 0.5) % R(B D, D* X ) R(B R(B i)! X) 95 % ( J.O ": 0.4) % [9] [9] [ J O] The results re sum mrized in Tble I, where we give 90 % C. L. upper limits on BB production, ssuming no nucler effect. We hve ver i f ied tht these limits re quite insensitive to the cuts. The most sensitive chnnel (like-sign dimuons) gives upper limits round nblnucleon for centrl B B production, 0 nblnucleon for diffrctive production. These limits re more thn one order of mgnitude lower thn previous results t the 11 interctions t 0 nb, only I i)!i)! event could be sme energy [I I ] ; they re consistent w ith the limits obtined from 190 nd 80 GeV l e [, 1 ]. F inlly, o n e c n notice t h t e v e n with ttributed, in our dt, to BB production. ( B B)

5 CONCLUSION. We hve given evidence for production of 1);1); events from 400 GeV le protons, with coss-section comptible with QCD predictions from gluon-gluon fusion mechnism. From like-sign dimuons, nd from events with 3 or 4 prompt muons we obtin upper limits on beuty meson production round some nnobrns for centrl models in the most sensitive chnnel. REFERENCES [l] J. Bdier et l., Phys. Lett. 114B (198) 457. [] J. Bdier et l., Phys. Lett. 14B (1983) 535. [ 3] R. E. Ecclestone nd D.M. Scott, Zeitschrift fiir Physik Cl9 (1983) 9. [4] B. Humpert nd P. Mery, Phys. Lett. 14B (1983) 65 nd Zeitschrift fiir Physik C0 (1983) 83. [5] J. Bdier et l., Nucl. Inst. nd Meth. 175 (1980) 319. [6] J. Bdier et l., Zeitschrift fiir Physik C6 (1985) 489. J. Bourotte, Thesis, U niversite Pris Sud, June 1983 (unpublished). [7] CDHS collbortion, H. Abrmowitz et l., Zeitschrift flir Physik Cl (198) 89. [8] S.N. Gnguli, Zeitschrift flir Physik C1 (1983) 163, nd references quoted within. [9] A. Chen et l., Phys. Rev. Lett. 5 (1984) [ 1 OJ S. Stone, Preprint CLNS , Sept. 83, Cornell. [11] A. Dimnt-Berger et l., Phys. Rev. Lett. 44 (1980) 507. [1] A. Ereditto et l., (NAlO collbortion) Preprint CERN EP , Jnury 1985 (submitted to Physics Letters B).

6 406 F I NAL STATE ± ).J l ).J or Number o f 1490 events in t r ge t s ( w i th good t im i n g ) Cuts on trnsver s e momentum ( G ev / c ) Other C u t s M ( µ 1 µ, )>4 $T ( $, µ µ )>90o M(µ M ( µ 1 µ, ) fm $ X F Numb e r o f e v e n t s fter cuts Acceptnce \, )>. 5 $ >!35o T M ( µ 1 µ, )>4 ( µ 1 µ, )>0 18±5 i. lo - ( centrl 4± l O- ' 3 1 9± 5 10±4 l o- 9 l o- M ( µ 1 µ, )fm $ M ( µ, µ, ) fm W 6±3 4 l o- produc t i on ) o ( BB ) 90% C L l im i t on ( centrl nb 14nb 0nb 0nb 40nb 0 nb 7 5 nb 00nb 40nb 300nb p r o d u c t i on ) ( BB ) 9 0 % CL l imi t on o ( d i f f r c t ive produc t i o n )

7 407 x l l e bl I I 10 II 1.6 -t m A \3 3 FIG 1.4 d (Cev c1 0 0 m,. MASS (GewC'} SUl1 4 S SUl't 4 S 91) -... qij-b -.. q9-bll -t'f q-brtr-'ft 0, q4-a B 99-ell-f"' w " qq-111!-,,. lc 1Q,., >OO,, lugo 1SOO 5 tuev11 _ 000 q11- Arb qq"- t 99-bb-t'f J q4-11ii ll _. H-'i''f ID q -... u " U ' > S!Gt\11) 1900 FlG

Transverse spin asymmetries at low momentum transfer at STAR

Transverse spin asymmetries at low momentum transfer at STAR Trnsverse spin symmetries t low momentum trnsfer t STAR Dmitry Svirid (ITEP) for the STAR Collbortion EDS Blois 2011 14th Workshop on Elstic nd Diffrctive Scttering, Qui Nhon, Vietnm, December 15-21, 2011