GSI – 13 March – 2004 ELISe collaboration Photonuclear Reactions at Storage Rings V. Nedorezov Institute for Nuclear Research RAS, Moscow, Photonuclear Laboratory

Photonuclear Laboratory Institute for Nuclear Research RAS, Moscow Synchrotron 35 MeV – 1947 Synchrotron 250 MeV – 1960 Linac 100 MeV Microtron 175 MeV - under manufacturing Kurchatov Institute, Moscow KSRS 2.5 GeV - since 2000 M.V.Lomonosov Moscow State University Microtron 80 MeV – since 2001 Photonuclear reactions at low and intermediate energies Electron scattering Photo and electro - fission Current International collaborations: A2 – Mainz - Experiments with real photons DELTA-SIGMA - Dubna - Spin effects in NN scattering GRAAL – Grenoble - Photoproduction of heavy mesons XI Int. Seminar “Electromagnetic interactions of Nuclei at Low and Medium Energies” is scheduled for 2006.

V.G.Nedorezov, A.A.Turinge, Yu.M.Shatunov «Photonuclear Experiments with Back Scattered Gamma Beams». UFN 47, 4, [2004]

Compton Beam Installations LadonTaladonРОККLEGSGRAALLEPS HI  S 121М Frascati Adone Novosibirsk VEPP 4, 3, 4М NSLSESRFSP-ring 8Duke Ее, GeV Ie, A W, eV – – E , MeV – –  /s

Virtual photons Electron Scattering Electromagnetic form-factor: ds/dW = ds/dW Mott x [(F1 gN )2 +t (F2 gN )2 + 2t ( F1 gN +F1 gN )2 tan2 (q/2)] t = Q2 /4MN2, F1,2 g,p = 2/3 F1,2 u - 1/3 F1,2 d - 1/3 F1,2 s, F1,2 gN = 2/3 F1,2 d - 1/3 F1,2 u - 1/3 F1,2 s

Physics features

Experimental features Internal target Backgrounds Bremsstrahlung – Luminosity monitor

Photon beam parameters Energy spectrumMonochromatizationPolarization Bremsstrahlung TaggingLinear or circular Up to 70% Positron annihilation in flight Coherent radiation from crystals Linear Up to 30% Compton back scattering of laser photons on electrons Tagging, Collimation Linear or circular Up to 100%

Compton Scattering Amplitude and dispersion relations: f = e’* e f 1 (w) + i w  e’* x e f 2 (w) e – EM field operator, s - Spin operator (nucleon). If w = 0 (low energy thorem): f1(0) = - (a / Z 2 / M ), f2(0) = (a k 2 / 2M 2 ), M – mass, a = e 2 /4  = 1/137 eZ – charge, k - anomalous magnetic moment of nucleon f 1 (0) = - (  / Z 2 / M ) +  2 /2  2  tot (w’)/f(  ’) d  ’ f2(0) = (  k 2 / 2M 2 ) +  2 /2  2  tot (  ’)/  ’) d  ’  ’  tot (  ) =  3/2 (  ) +  1/2 (  ),  tot (  ) =  3/2 (  ) -  1/2 (  ), Sum rule GDH : Y = (  3/2 (  ) +  1/2 (  )) d  = 2  2  k 2 /M 2

Compton Back Scattering Method Laser (hw = 2.34 эВ) Gamma beam Electron beam Е = 140 МeV Е = 2.5 GeV Be Mirror Intensity (gammas/s): Argon (UV) 10 7 СО 2 (IR) FEL Recirculation 10 15

Basic relations n =  ,  = E e /m e, = 2   /E e, K = 1 + n + ,  = {  1,  2,  3 ), x = 2pk/m 2, y = 2pk’/m 2. ,  –  emission angle; к,k’и p,p’ - initial and final momentum of photon and electron  = {  1,  2,  3 ) – Stock’s parameters

Gamma beam parameters Energy Spectrum Linear polarization Circular polarization

Conclusion Real and virtual gamma beams High intensity Compton and Bremsstrahlung beams Coulomb dissociation of Heavy Ions Electron scattering. E- HI colliders