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STATUS OF THE PROJECT ANKE-COSY

STATUS OF THE PROJECT ANKE-COSY. Introduction Deuteron breakup at high momentum transfer Forward detector system performance Experimental results and discussion Participation in other ANKE experiments Conclusions. 18 January 2005. ANKE Collaboration.

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STATUS OF THE PROJECT ANKE-COSY

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  1. STATUS OF THE PROJECT ANKE-COSY • Introduction • Deuteron breakup at high momentum transfer • Forward detector system performance • Experimental results and discussion • Participation in other ANKE experiments • Conclusions 18 January 2005

  2. ANKE Collaboration V. Abaev1, H.-H. Adam2, N. Amaglobeli3, S. Barsov1, U. Bechstedt5, W. Borgs5, M. Büscher5, W. Cassing6, V. Chernetsky7, V. Chernyshev7, B. Chiladze3, D. Chiladze5,3, M. Chumakov7, V. Dimitrov8, M. Drochner4, S. Dymov5,9, A. Dzuba1,5, R. Engels5, W. Erven4, P. Fedorets7, L. V. Filkov10, A. Gerasimov7, Ye. S. Golubeva11, V. Goryachev7, O. Grebenyuk1, K. Grigoriev1, V. Grishina11, D. Gusev9, Ch. Hanhart5, G. Hansen12, M. Hartmann5, V. Hejny5, L. Jarczyk13, A. Kacharava15, N. Kadagidze9, B. Kamys13, M. Karnadi5, V. L. Kashevarov10, I. Keshelashvili5,3, A. Khoukaz2, St. Kistryn13, V. Kleber14, F. Klehr12, H. Kleines4, H. R. Koch5, V. I. Komarov9, L. Kondratyuk7, E. S. Konobeevski11, V. Koptev1, A. Kovalov1, P. Kravchenko1, P. Kravtsov1, T. Krings5, V. Kruglov9, P. Kulessa16, A. Kulikov9,17,A. Kurbatov9, N. Lang2, N. Langenhagen8, I. Lehmann5,8, V. Leontiev9,17, H. Loevenich4, B. Lorentz5, S. Lorenz15, G. Macharashvili3,9, Y. Maeda5, R. Maier5, R. Menke2, T. Mersmann2, S. Merzliakov9, M. Mikirtychiants5, S. Mikirtychiants1, H. Müller8, A. Mussgiller5, M. Nekipelov5, R. Nellen5, V. Nelyubin1, M. Nioradze3, H. Ohm5, S. I. Potashev11, D. Prasuhn5, D. Protic5, K. Pysz16, F. Rathmann5, B. Rimarzig8, Z. Rudy13, J. Sarkady4, H. Paetz gen. Schieck14, R. Schleichert5, F. Schmidt15, H. Schneider5, H. Seyfarth5, A. Sibirtsev5, K. Sistemich5, E. Steffens15, H. J. Stein5, H. Ströher5, A. Strzalkowski13, S. Trusov17,9,Yu. Uzikov9, Yu. Valdau1,5, A. Vassiliev1, A. Volkov9, K.-H. Watzlawik5, J. Wessels2, C. Wilkin18, A. Wronska5, P. Wüstner4, S. Yashenko15,9, B. Zalikhanov9,N. Zhuravlev9, K. Zwoll4, I. Zychor19.

  3. 1High Energy Physics Department, Petersburg Nuclear Physics Institute, Gatchina, Russia 2Institut für Kernphysik, Universität Münster, Münster, Germany 3High Energy Physics Institute, Tbilisi State University, Tbilisi, Georgia 4Zentrallabor für Elektronik, Forschungszentrum Jülich, Jülich, Germany 5Institut für Kernphysik, Forschungszentrum Jülich, Jülich, Germany 6Institut für Theoretische Physik, Universität Gieβen, Gieβen, Germany 7Institute for Theoretical and Experimental Physics, Moscow, Russia 8Institut für Hadronen und Kernphysik, Forschungszentrum Rossendorf, Dresden, Germany 9Laboratory of Nuclear Problems, Joint Institute for Nuclear Research,Dubna, Russia 10Lebedev Physical Institute, Moscow, Russia 11Institute for Nuclear Research, Russian Academy of Sciences, Moscow, Russia 12Zentralabteilung Technologie, Forschungszentrum Jülich, Jülich, Germany 13Institute of Physics, Jagellonian University, Cracow, Poland 14Institut für Kernphysik, Universität Köln, Köln, Germany 15Physikalisches Institut II, Universität Erlangen-Nürnberg, Erlangen, Germany 16Institute of Nuclear Physics, Cracow, Poland 17Dubna Branch , Moscow State University, Dubna, Moscow Region, Russia 18Physics Department, Univ. College London, London, Great Britain 19The Andrzej Soltan Institute for Nuclear Studies, Swierk, Poland

  4. Spectrometer ANKE Triplet of magnets with several detector groups. Forward and Backward Detectors were proposed and produced byJINR physicistsfor thedeuteron breakup study program. The Forward detector is used in awide range of experiments at ANKE.

  5. Deuteron Breakup at High Momentum Transfer A general problem: hadron-nucleus interaction at high momentum transfer to more than one quasifree nucleon ─ Study of a short–distance structure of nuclear matter q ≳ 0.4 GeV/c → rNN ~ 1/q ‹ 0.5 fm nucleon radius ~ 0.86 fm overlapping nucleons At which energies does the hadronic approach fail and effects of the quark-gluon nature do appear?

  6. The simplest cumulativeprocess with 3-particle final state: p+d→(NN)forward + p+ddforward +pbackward d — T=0, S=1 p+d→(pp)sforward +nbackward Epp<3MeV,(pp)s ― T=1, S=0 ∆-isobar and πN(T=1/2, 3/2) suppression Node in S-wave Ψpp(q) at q≈0.4 GeV/c Yu.N.Uzikov(1990), (2002) More clean and transparent interpretation in the framework of the hadronic approach The task: study of the deuteron breakup process in the most informative way which includes ― complete kinematical reconstruction ― measurement of polarization observables.

  7. Forward Detector System PerformanceB. Chiladze, et al. Part. and Nuclei, Lett. №4 (2002) 95S. Dymov et al. Part. and Nuclei, Lett. №2 (2004) 40 A noticeable acceptanceof ANKE for forward emitted particles: polar angle θp= 0°-11° rigidity/Pbeam = 0.3-1.25 Θxz-p acceptance at 0.8 GeV beam energy.

  8. Identification of the processes does not require particle mass identification (!) Momentum correlation in double-track events at 0.8 GeV beam energy +

  9. Missing mass accuracy σ(Mx) = (17.5 ± 0.7) MeV for pppp σ(Mx)/Mp= 1.9% σ(p)/p = 0.5% - 1.0% σ(θp) ≃0.2º The setup provides: momentum resolution time resolution σ(∆t) = 200 ps Sufficiently high relative energy (Epp) resolution (in cms of the proton pair) in the Epp range of 0.2-5.0 MeV Simulated (pp) excitation energy resolution for pd(pp)n at 0.7 GeV

  10. Time-of-flight difference measured versus calculated one (assuming both particles are protons). • Particle identification using • momentum • energy losses in two consecutive scintillator planes • Cherenkov radiation amplitudes • time-of-flight difference for double-track events, σ(∆t) = 200 ps p + dp pp 3 + + Hp pp pd d + pp d pd p 3 + Hp + dp DE1 DE2 Energy loss distribution in counters of two consecutive planes

  11. Missing mass (Selected: Epp, Ytarg, cosθ<0.7) Experimental Results and Discussion p+d(pp) +n at the proton beam energy E = 0.6, 0.7, 0.8, 0.95, 1.35, 1.9 GeV s First observation at intermediate energies The data at E = 1.1, 1.4 and 2.0 GeV are also obtained and are in the stage of analysis.

  12. Model-independent determination of dσs(t) =FSIs(t)·K·|As(t)|2 for pd(pp)sn and pd(pn)tp Energy Dependence of the Differential Cross Section pd(pp)n cross section integrated over 0 <Epp<3 MeV averaged in the interval 172º-180º V. Komarov et al., Phys. Lett. B553 (2003) 179 Yu.Uzikov et al. Eur.Phys.J. A18(2003)317

  13. Description in the framework of theONE+SS+Δ Model L.A. Kondratyuk et al (1981) Yu.N. Uzikov (2002) Strong contradictionof the model usingParis or RSCNN potentials Qualitative agreementof the model withCDBonnpotentials J. Heidenbauer, Yu. Uzikov Phys. Lett. B562 (2003) 227 Conclusion:the description is strongly sensitive to the short range behaviour of the NNpotentials and definitely prefersthe deuteron more soft at short distancesthan theParis or Reid Soft Core potentials present.

  14. Description in Bethe-Salpeter Approach: L.P Kaptari, et al (1997) L.P. Kaptari, et al (2003) Conclusion:Evidence for P-wave component contamination. But: Only ONE mechanism is exploited. Further experimental data are required to test validity of the hadronic approaches for the process description: - proton pair excitation spectra and angular distribution of the pair relative momentum - measurement of polarization observables

  15. Polarization measurements E = 0.5, 0.8 GeV  p • Vanishing of Ayp at 0.8 GeV, expected in the ONE+SS+∆ model • High value of Ayp at 0.5 GeV, contradicting the model Spin structure of the ΔΝ amplitude? Analyzing power Ayp(θn) Submitted for publication inPhys. Rev. Letters Data handling to obtain the Epp and θrt distributions is in progress

  16. Outlook ABS polarized target is developed and constructed in IKP Jülich Installation of the ABS-target at ANKE and commissioning are planned for 2005.(Approved by the COSY PAC in November 2004.) The needed maintenance and beam time is allocated. T20and Cyyobservables may be predicted in the model much more reliable than the observable . They will be measured with both the beam and the target polarized. Experiments with polarized deuteron target (2005-2008) Study of the pdppn process in the (Forward Detector)*(Backward Detector) configuration is foreseen as well.

  17. Participation in Other Experiments at ANKE Various experiments on mesonproduction(h,f,K,w,a ) in pp, pd, dp, dd interactions Charge exchange deuteron breakup, dp(pp)n including - maintenance and upgrade of the Forward Detector - proposal preparation - software development - trigger upgrade - measurements - data analysis 0

  18. List of ANKE publications with JINR co-authors in 2004 Experiment ● Near-threshold production of omega-mesons in the pnd+w reaction. Eur. Phys. J. A21 (2004) 521 S. Barsov, ...S. Dymov, A. Kacharava, V. Komarov, G. Macharashvili, S. Merzliakov, A. Petrus, Yu. Uzikov, B. Zalikhanov, et al. ●Measurement of the analyzing power in pd (pp)n with a fast forward S diproton S . Yaschenko et al. Submitted to Phys.Rev.Lett. Instrumentation • Spectator detection for the measurement of proton-neutron interaction at ANKE. I. Lehmann, …, S. Merzliakov, S. Trusov et al. Nucl. Instr. and Methods V530/3 (2004) 275 • The forward detector of the ANKE spectrometer. Tracking system and its use in data analysis. S. Dymov, A. Kacharava, V. Komarov, A. Kulikov, V. Kurbatov, G. Macharashvili, A. Petrus, S. Yaschenko, B. Zalikhanov, N. Zhuravlev Part. and Nucl., Lett. No2 (2004) 40 Theory and analysis • Subthreshold antiproton production in proton-carbon reactions. V.Komarov, H. Mueller, A. Sibirtsev J. Phys. G: Nucl. Part. Phys. 30 (2004) 921 • Subthreshold antiproton production in pC, dC and αC reactions. H. Mueller, V. KomarovJ. Phys. G: Nucl. Part. Phys. 30 (2004) 1379 1  0

  19. Conclusions • Performance of the ANKE setup is adequate to a scientific goal of fundamental character stated in the project. • First exclusive study of the deuteron breakup in kinematics close to that of the backward pd elastic scattering is performed. • The experimental results are not completely described by current models in the framework of the meson-nucleon approach. The experiment gives a tool for further insight into the short-range structure of a nuclear matter. More refined theoretical description demands new experimental data. • The next stage of the study, with use of polarized deuteron target, starts in 2005. In addition to polarization physics at ANKE itself, it will be an important step towards the proposed future measurements with PAX at GSI. • The JINR group is strongly involved in the whole physical program of ANKE.

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