1. S.V. Afanasiev, 1 A.S. Artiomov, 1 R.N. Bekmirzaev 2, D.K. Dryablov, 1 Z.A. Igamkulov, 1 V.I. Ivanov, 1 A.Yu. Isupov, 1 D.M. Jomurodov, 1 A.I. Malakhov, 1 V.Matousek 3, M.Morhac 3 A.I. Lebedev, 4 A.I. L’vov, 4 L.N. Pavlyuchenko, 4 E.B. Plekhanov 1, V.V. Polyansky, 4 S.S. Sidorin, 4 G.A. Sokol 4, M.U. Sultanov 5, I.Turzo 3 "Search Results for Eta-Mesic Nuclei in the d+C Reaction in JINR" E-mail: afanasev@lhe.jinr.ru Hadron Structure 2011 afanasev@lhe.jinr.ru Tatranská Štrba, June 30th LHEP JINR Dubna

2. The properties of hadrons in nuclear medium are one of the interesting topics of the modern hadron and nuclear physics. All nuclei have essentially smaller mass than sum of masses all neutrons and the protons formed nuclei. The difference of masses is a result of strong interaction between hadrons which formed composite system. It is possible to assume, that particles, distinct from nucleons such as an  - meson, in nuclear medium will have smaller mass than in a free state. Motivation Hadron Structure 2011 Tatranská Štrba, June 30th a new field in studies on nuclear and particle physics. new data on the  -meson and the S 11 (1535) resonance interactions with nucleons determination of the energy levels E_g (S 11 ) and E_g(  ) and their widths  g (S 11 ) and  g (  ) in the  -nucleus determine mass shift  m(S 11 ) and  m(  ) in the nuclear medium A possibility to perform studies on physics of  - mesic nuclei at the JINR nuclotron internal beam reaction p+A  n+p+  (A - 1) or d+A  n+p+n+  (A - 1) elementary process p+n*  n+S + 11 (1535)*  n+ p +  * Physical aims afanasev@lhe.jinr.ru

3. afanasev@moonhe.jinr.ru Tatranská Štrba, June 30th K. Tsushima Nuclear Physics A670 (2000) 198c-201 c, “Study o f , ,  ' and D -- mesic nuclei” K. Tsushima, D.H. Lu, A.W. Thomas, K. Saito Physics Letters B 443 1998 26–32, “Are  - and  -nuclear states bound.” A. I. L'VOV nucl-th/9809054 PRODUCTION AND DECAY OF ETA -MESIC NUCLEI Proposed mass shift for S 11  m(S 11 ) = (24÷30) η + (8) N =30-40 MeV In nuclear medium Hadron Structure 2011

4. afanasev@moonhe.jinr.ru Tatranská Štrba, June 30th Formation of an η mesic nucleus and its decay via emission of back-to-back nucleon-pion pairs. Photoproduction of mesons from nuclei - In-medium properties of hadrons B. Krusche, nucl-ex/0411033 Hadron Structure 2011

5. afanasev@lhe.jinr.ru Formation, evolution an decay Proposed formation in NN interaction p+A  p+n+  (A - 1) ( 13 C- prefer ) n+A  n+p+  (A - 1) Investigate d+A 1   A 2 (S 11 )   +p+... Evolution in the elementary process S 11 (1535)*  N +  Decay to the  -N, N-N and  -  channels 0.9 0.1 10 -5 Hadron Structure 2011 Tatranská Štrba, June 30th Scheme of the resonance formation In the elemental NN interaction produced  or  mesons at 180 o. N(1535)S 11 I(J P )=1/2 ( 1/2 - ) L( ,  ) =0 Mass m=1520 to 1550 (  1535) MeV Full width  =100 to 250 (  150) MeV L.C.Liu Phys. Rev. C 40 p.832

6. Hadron Structure 2011 afanasev@lhe.jinr.ru Tatranská Štrba, June 30th Bounding energy P p = P d p+A  d+  p=0 +(A-1) p=0 d+A  t+  p=0 +(A-1) p=0 P d = P t E d = 2.22MeV E t = 6.25MeV 1)  -meson production 2) To produce stable nucleus-rest from target 3) Effective capture of the meson 4) To measure the products of decay 13 C +d= 12 C+t+Q Q=1.3 MeV

7. afanasev@lhe.jinr.ru Hadron Structure 2011 Tatranská Štrba, June 30th 13 C(p,d) 12 C 13 C(d,t) 12 C Kinematic of recoil-free transfer reaction

8. afanasev@lhe.jinr.ru Estimates of the effect yield Y(p  )  1400 events Y(pp)  230 events Y(p  p)  250 events Y(ppp)  40 events Y(pnp  )  35 events Y(pnpp)  6 events Y(p,  - )= L    (p 12 C  p 1 p 2 n  (A-1))  Br(  N)       n c  f(  p /   )   - total cross section of eta-nuclei formation; L - luminosity;   - the solid angle;  - the probability to have the  p pair f(  p /   ) - a geometric fraction; Br(  N) - the branching ratio of S 11 (1535) decay; n c - accelerator cycles per hour; Hadron Structure 2011 Tatranská Štrba, June 30th Production of  -mesons in nucleon-nucleon collisions V. Baru, PHYSICAL REVIEW C 67, 024002 (2003)

9. afanasev@lhe.jinr.ru Experimental setup K-arm K1 - Start counter K2 - Trigger & Cherenkov counters K3 - TOF - wall K4 - E-counter K5 - Veto counterP-arm P1 - Start counter P2 - Trigger & Cherenkov counters P3 - TOF - wall P4 - E-counter P5 - Veto counter Hm - Ring counter N - Neutron detector An - Neutron-Veto FL,FR,BL,BR - Monitors Hadron Structure 2011 Tatranská Štrba, June 30th

10. Target -1 -- 12 C, 8 wires x 8 mkm Target -2 -- 27 Al, 1 mm strip x 10 mkm Target -3 - - 64 Cu, 8 wire x 50 mkm Target -4 - - 183 W, 1 wire x 20 mkm Target -5 -- 108 Ag, 1 mm strip x 20 mkm Target -6 -- CH 2, 1 mm strip x 10 mkm Construction of the Internal Target Station Dimension of the target region PMT for light control Hadron Structure 2011 Tatranská Štrba, June 30th afanasev@lhe.jinr.ru

11. afanasev@lhe.jinr.ru Setup of the experimental RUN The geometry of the experiment P-arm K-arm Hadron Structure 2011 Tatranská Štrba, June 30th

12. Reconstracted mass (confidence level > 95%) Effective mass Hadron Structure 2011 Tatranská Štrba, June 30th afanasev@lhe.jinr.ru  M  5 MeV/c 2  TOF  0.2 ns

13. Effective mass formation in dA reaction at the energy 1.5 GeV/nuc (a) (b) (c) Hadron Structure 2011 Tatranská Štrba, June 30th afanasev@lhe.jinr.ru Counts/10MeV/c 2

14. Effective mass formation in dC reaction at the energy 1.9 GeV/nuc The yield of proton-pion pairs: Hadron Structure 2011 Tatranská Štrba, June 30th afanasev@lhe.jinr.ru   p  170 0   p  180 0 Y( ,p)  1.4  1.8 GeV/c 2

15. Effective mass formation in dC reaction at the energy 2.0 GeV/nuc New data 2010 Hadron Structure 2011 Tatranská Štrba, June 30th afanasev@lhe.jinr.ru Y( ,p)  2.0 GeV/c 2 Best fit is Gaussian + constant Mean 1465.1 MeV Sigma 27.2 MeV Constant 1310 Distribution after rejection of the constant level Δ S 11 In medium Total events under picks ≈2000 N(1535)S 11 I(J P )=1/2 ( 1/2 - ) L( ,  ) =0 Mass m=1520 to 1550 (  1535) MeV Full width  =100 to 250 (  150) MeV S 11 ΔM≈70 MeV 180 0

16. The value of the total cross-section of the process can be found based on the number of inelastic interactions dC, measured on the accounts of monitor telescopes, and the simulation results using the software package GEANT and RQMD. Hadron Structure 2011 Tatranská Štrba, June 30th afanasev@lhe.jinr.ru Newest data 2010 give the similar result for p-π pars

17. afanasev@lhe.jinr.ru Conclusions Have been measured the energy-sum and the angular correlation of two nucleon pairs  p emitted in the d+C reaction. It have been clearly observed a distinct  p back-to- back correlation coming from a target, which may be associated with the signature of two-body final state. Data analyses are shown resonance structure formed in the target at the energy region of primary beam 1.5-2.0 GeV/nucl. The resonance is shifted to small masses an shift has value around 70 MeV and width of the rsonance is 63 MeV. I t disagree theoretical predictions. The value of the total cross-section is estimated  10  b. Hadron Structure 2011 Tatranská Štrba, June 30th

18. Hadron Structure 2011 afanasev@lhe.jinr.ru Tatranská Štrba, June 30th New proposal for η–nuclear study on nuclotron. d+A 1   A 2 (S 11 )   - +p+... d+A 1   A 2 (S 11 )   + +n+... d+A 1   A 2 (η+d*)  p +n+... η+d  p +n

19. Hadron Structure 2011 afanasev@lhe.jinr.ru Tatranská Štrba, June 30th Collaboration S.V. Afanasiev, A.S. Artiomov, D.K. Dryablov, Z.A. Igamkulov, V.I. Ivanov, A.Yu. Isupov, A.I. Malakhov, 1 E.B. Plekhanov Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia V.Matousek, M.Morhac, I.Turzo Institute of Physics, Slovak Academy of Sciences, Slovak republic S. VokálJ. Vrláková, A. Kravčáková, A. Dirner, M. Špavorová, Faculty of Science, University of P.J. Šafárik, Košice, Slovak republic A.I. Lebedev, A.I. L’vov, L.N. Pavlyuchenko, V.V. Polyansky, S.S. Sidorin, G.A. Sokol, Lebedev Physical Institute, Leninsky Prosect 53, Moscow 117924, Russia D.M. Jomurodov, R.N. Bekmirzaev, Jizzakh State Pedagogical Institute, Uzbekistan M.U. Sultanov, Samarkand State University, Uzbekistan

20. afanasev@lhe.jinr.ru Thank you for attention! Hadron Structure 2011 Tatranská Štrba, June 30th

21. Hadron Structure 2011 afanasev@lhe.jinr.ru Tatranská Štrba, June 30th The SCAN spectrometer can register only tail of Δ-resonance. Momentum of protons is limited P p >230 МэВ/с.

22. Hadron Structure 2011 afanasev@lhe.jinr.ru Tatranská Štrba, June 30th Numerical calculation p+A  d+  p=0 +(A-1) p=0 d+A  t+  p=0 +(A-1) p=0 d+A  3 He+  p=0 +(A-1) p=0 (p) ( 3 He)

23. Hadron Structure 2011 afanasev@lhe.jinr.ru Tatranská Štrba, June 30th