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Institute for Nuclear Research. Intra-Nuclear Cascade (INC) code for simulation of meson photo production in nuclei. A.Ignatov for the GRAAL collaboration. Erice, 2007. New approach to study interaction of unstable short living mesons with nuclear medium. Using the recoil nucleon as a tagger.
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Institute for Nuclear Research Intra-Nuclear Cascade (INC) code for simulation of meson photo production in nuclei A.Ignatov for the GRAAL collaboration Erice, 2007
New approach to study interaction of unstable short living mesons with nuclear medium Using the recoil nucleon as a tagger
INC – Intra-nuclear Cascade[Moscow, EMIN-2001, p.170 ] Probability of secondary interactions between meson and intra-nuclear nucleon : where s – cross section, r - nuclear density (0.17 Fm-3), l – free mean path. s = stot (hN) = sel ( hN) + sin ( hN). Probability for zero and one interaction step within INC : The ratio = 6.7 for slow h –mesons (s =150 mb) Life time of unstable mesons depends on its velocity; for slow h– mesons the free mean path l = 3 Fm.
INC prediction for different cascade steps[Moscow, EMIN-2001, p.170 ]
GEANT+INC code simulation Correlation between momentum of the primary recoil proton and angle of its emission • Eg=1.4-1.5 GeV • 14N target • Kinematics included
GRAAL FACILITY 1 - interaction region (laser + electron beams), 7 - MWPCs 2 - tagger, 8 - Double plastic wall 3 - laser 9 – Shower wall 4 - collimators 10 – thin monitors 5 - backward detector 11 – Total absorption detector 6 – target + cyl.MWPCs + Barrel + BGO-ball
Experimental and simulated ToF measurements De vs ToF correlation from experimental data on deutron All charged particles in forward direction are selected Experiment Simulations gp->p0p gp->hp
Angle vs momentum of primary recoil proton Experiment on deutron (GRAAL data) Simulations with INC+LAGGEN code on 14N nucleus Kinematics not included!
Momentum of primary recoil proton vs momentum of all secondary particles GEANT+INC simulation 14N target proton: Pp=Pmax q<25(forward direction) Different steps of the reaction are clearly seen
Conclusion: • Simulation shows the possibility to study interaction of h-mesons with nuclear medium, using the recoil nucleons as a tagger. • GRAAL data on the deutron shows that this problem can be solved experimentally. • Experiment on light nucleus is expected.