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ASSIA LOI

ASSIA LOI. V. Abazov 1 , G. Alexeev 1 , M. Alexeev 2 , A. Amoroso 2 , N. Angelov 1 , M. Anselmino 3 , S. Baginyan 1 , F. Balestra 2 , V. A. Baranov 1 , Yu. Batusov 1 , I. Belolaptikov 1 , R. Bertini 2 , N. Bianchi 11 , A. Bianconi 4 , R. Birsa 13 ,

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ASSIA LOI

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  1. ASSIA LOI V. Abazov1, G. Alexeev1, M. Alexeev2, A. Amoroso2, N. Angelov1, M. Anselmino3, S. Baginyan1, F. Balestra2, V. A. Baranov1, Yu. Batusov1, I. Belolaptikov1, R. Bertini2, N. Bianchi11, A. Bianconi4, R. Birsa13, T. Blokhintseva1, A. Bonyushkina1, F. Bradamante13, A. Bressan13, M. P. Bussa2, V. Butenko1, M. Colantoni5, M. Corradini4, S. DallaTorre13, A. Demyanov1, O. Denisov2, E. De Sanctis11, P. DiNezza11, V. Drozdov1, J. Dupak9, G. Erusalimtsev1, L. Fava5, A. Ferrero2, L. Ferrero2, M. Finger6, M. Finger7, V. Frolov2, R. Garfagnini2, M. Giorgi13, O. Gorchakov1, A. Grasso2, V. Grebenyuk1, D. Hasch11, V. Ivanov1, A. Kalinin1, V. AKalinnikov1, Yu. Kharzheev1, N. V. Khomutov1, A. Kirilov1, E. Komissarov1, A. Kotzinian2, A. S. Korenchenko1, V. Kovalenko1, N. P. Kravchuk1, N. A. Kuchinski1, E. Lodi Rizzini4, V. Lyashenko1, V. Malyshev1, A. Maggiora2, M. Maggiora2, A. Martin13, Yu. Merekov1, A. S. Moiseenko1, V. Muccifora11, A. Olchevski1, V. Panyushkin1, D. Panzieri5, G. Piragino2, G. B. Pontecorvo1, A. Popov1, S. Porokhovoy1, V. Pryanichnikov1, M. Radici14, P. G. Ratcliffe12, M. P. Rekalo10, P. Rossi11, A. Rozhdestvensky1, N. Russakovich1, P. Schiavon13, O. Shevchenko1, A. Shishkin1, V. A. Sidorkin1, N. Skachkov1, M. Slunecka7, A. Srnka9, V. Tchalyshev1, F. Tessarotto13, E. Tomasi8, F. Tosello2, E. P. Velicheva1, L. Venturelli4, L. Vertogradov1, M. Virius9, G. Zosi2 and N. Zurlo4 1Dzhelepov Laboratory of Nuclear Problems, JINR, Dubna, Russia 2Dipartimento di Fisica ``A. Avogadro'' and INFN - Torino, Italy 3Dipartimento di Fisica Teorica and INFN - Torino, Italy 4Università and INFN, Brescia, Italy 5Universita' del Piemonte Orientale and INFN sez. di Torino - Italy 6Czech Technical University , Prague, Czech Republic 7Charles University, Prague, Czech Republic 8DAPNIA,CEN Saclay, France 9Inst. of Scientific Instruments Academy of Sciences,Brno, Czech Republic 10NSC Kharkov Physical Technical Institute, Kharkov, Ukraine 11Laboratori Nazionali Frascati, INFN, Italy 12Università dell' Insubria,Como and INFN sez. Milano, Italy 13University of Trieste and INFN Trieste, Italy 14INFN sez. Pavia, Italy

  2. SIS300 @ GSI: • A complete description of nucleonic structure requires: • @ leading twist and @ NLO • Physics objectives: Introduction • proton and gluon distribution functions • quark fragmentation functions • Drell-Yan di-lepton production • Single spin asymmetries • Spin observables in , production • Time like electromagnetic form factors

  3. κT-dependent Parton Distributions Twist-2 PDFs f1, g1 studied for decades: h1 essentially unknown

  4. Drell-Yan Di-Lepton Production 3 planes: plane to polarisation vectors plane plane plenty of (single) spin effects Why Drell Yan? Asymmetries depend on PD only (SIDIS→convolution with QFF) Why ? Each valence quark can contribuite to the diagram Kinematics

  5. Drell-Yan Di-Lepton Production Scaling: Full x1,x2 range . needed [1] Anassontzis et al., Phys. Rew. D38 (1988) 1377

  6. Drell Yan Asymmetries — Unpolarised beam and target Di-Lepton Rest Frame NLO pQCD: λ 1,   0, υ 0 Experimental data [1]: υ 30 % [1]J.S.Conway et al., Phys. Rev. D39(1989)92. υinvolves transverse spin effects at leading twist [2]: cos2φ contribution to angular distribution provide: [2]D. Boer et al., Phys. Rev. D60(1999)014012.

  7. Angular distribution in CS frame E615 @ Fermilab -N  +-X @ 252 GeV/c -0.6 < cos < 0.6 4 < M < 8.5 GeV/c2 • cut on PT selects asymmetry • 30% asymmetry observed for - Conway et al, Phys. Rew. D39 (1989) 92

  8. Drell-Yan Asymmetries — Unpolarised beam, polarised target λ 1,   0 Even unpolarised beam is a powerful tool to investigate кT dependence of QDF D. Boer et al., Phys. Rev. D60(1999)014012.

  9. Drell-Yan Asymmetries — Polarised beam and target Uncorrelated quark helicities access chirally-odd functions TRANSVERSITY • Ideal because: • h1 not to be unfolded with fragmentation functions • chirally odd functions • not suppressed (like in DIS)

  10. Drell-Yan Asymmetries — Polarised beam and target To be corrected for: NH3 polarised target:

  11. Beam and Target ? ? ASSIA

  12. Beam and Target Key features: Generation of intense, high-quality secondary beams of rare isotopes and antiprotons. Two rings: simultaneous beams. SIS 100 Tm SIS 300 Tm U: 35 AGeV p: 90 GeV

  13. Sketch of the apparatus MINIDC : drift type detectors like GEMs and MEGA DC : small drift type detectors with high spatial resolution + larger detectors with dead central area

  14. Experimental setup Possible setup scheme similar to the COMPASS first spectrometer • SM1 magnet ( 1Tm, stands ) • GEM,MICROMEGA detetors smaller angle • MWPC, STRAW detectors larger angle • expected resolution • vertex resolution • HODOSCOPEs → Trigger • sandwiches iron plates, Iarocci tubes, scintillator slabs → Id • beam vacuum pipe along the apparatus

  15. Beam and Target NH3 10g/cm3 : 2 x 10cm cells with opposite polarisation • GSI modifications: • extraction SIS100 → SIS300 • or injection CR → SIS300 • slow extraction SIS300 → beamline adapted to • experimental area adapted to handle expected • radiation from

  16. Alternative GSI solution HESR collider polarised p and beams • Luminosity comparable to external target → KEY IUSSUE • dilution factor f~1 • difficult to achieve polarisation Pp ~ 0.85 • required achievable with present HESR performances • (15 GeV/c) • only transverse asymmetries can be measured • p↑-beam required polarisation proton source and • acceleration scheme preserving polarisation • no additional beam extraction lines needed • EXPERIMENTAL SETUP COMPLETELY DIFFERENT

  17. Fermilab E866 800 GeV/c 80 60 45 30 no K-factor, continuum contribution only ∫dM2 between 6 and 16 = (2.6, 7.8, 13, 20) 10-7GeV-2

  18. Phase space for Drell-Yan processes  = const: hyperbolae xF = const: diagonal 15 GeV/c PANDA 30 GeV/c ASSIA 40 GeV/c

  19. A. Bianconi (ASSIA col.)

  20. REQUIREMENTS FOR THE DRELL-YAN MODEL Here, as well as in the parton model, Impulse approximation is required dilepton massM² large, s very large, but M² /s finite “If we want to find processes which satisfy the kinematical constraints allowing application of the impulse approximation we need look for interactions at high energies s which absorb or produce a lepton system of huge mass M² such that the ratio M² /sis finite“. S.D. Drell and T.-M. Yan Phys. Rev. Lett. 25 (1970) 316 Therefore s must be of the order of 100, that is T ≥ 40 GeV for M² in the `safe` region. No data below T= 30 GeV Other possibility: the collider mode luminosity?

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