Cem Güçlü İstanbul Technical University Physics Department

1. Physics of Ultra-Peripheral Nuclear Collisions Cem Güçlü İstanbul Technical University Physics Department Workshop on “High energy photon collisions at the LHC

2. Particle production from EMFields * Lepton-pair production * Beam Lifetime (electron capture) * Detector background * Non-perturbative and perturbative approach * Impact parameter dependence * Multi-pairproduction * Test of QED at high fields Workshop on “High energy photon collisions at the LHC

3. Collision Parameters : Workshop on “High energy photon collisions at the LHC

4. SPS 10 100 120 12 1.6 RHIC 100 10000 12000 1200 160 Relativistic Colliders Workshop on “High energy photon collisions at the LHC

5. Collisions of Heavy Ions Workshop on “High energy photon collisions at the LHC

6. Dirac wave-function of electrons/positrons Electromagnetic vector potential Electromagnetic field tensor Workshop on “High energy photon collisions at the LHC

7. Lepton-Pair Production Semi Clasical Action : Free Lagrangian : Interaction Lagrangian : Workshop on “High energy photon collisions at the LHC

8. Four Vector Potentials of the Colliding Ions : Workshop on “High energy photon collisions at the LHC

9. Ion 1 Ion 2 time Pair Production Emits photon Emits photon Workshop on “High energy photon collisions at the LHC

10. Direct and exchange diagrams : Workshop on “High energy photon collisions at the LHC

11. Total Cross Section Workshop on “High energy photon collisions at the LHC

12. Scalar part of EM Fields in momentum space of moving heavy ions Workshop on “High energy photon collisions at the LHC

13. Free electron-positron pair production SPS , γ=10, Au + Au , σ=140 barn RHIC, γ=100, Au + Au , σ=36 kbarn LHC, γ=3400, Au + Au , σ=227 kbarn Bound- free electron-positron pair production RHIC, γ=100, Au + Au , σ=83 barn LHC, γ=3400, Au + Au , σ=161 barn Pb + Pb, σ=206 barn Workshop on “High energy photon collisions at the LHC

14. Impact Parameter Dependence Cross Sections : Workshop on “High energy photon collisions at the LHC

15. Workshop on “High energy photon collisions at the LHC

16. Workshop on “High energy photon collisions at the LHC

17. Workshop on “High energy photon collisions at the LHC

18. Two Photon Method : Equivalent Photon Method: M. C. Güçlü, Nucl. Phys. A, Vol. 668, 207-217 (2000) Workshop on “High energy photon collisions at the LHC

19. Workshop on “High energy photon collisions at the LHC

20. Workshop on “High energy photon collisions at the LHC

21. Born Approximation with Coulomb Corrections R.N.Lee at al, Phys. Rev. A 64, 032106 (2001) Workshop on “High energy photon collisions at the LHC

22. Workshop on “High energy photon collisions at the LHC

23. Workshop on “High energy photon collisions at the LHC

24. Workshop on “High energy photon collisions at the LHC

25. Small momentum approximation M.C. Güçlü at al. Phys. Rev. A 72 022724 (2005). Workshop on “High energy photon collisions at the LHC

26. Experiments at CERN Super Proton Synchroton SPS Workshop on “High energy photon collisions at the LHC

27. Energy = 200 A GeV at fixed target frame Measured Cross Section for 1-17 MeV /c positron yield with 25% error for 1-17 MeV /c positron For all positron momenta Vane CR at al. Phys. Rev. A 50:2313 (1994). Workshop on “High energy photon collisions at the LHC

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29. Workshop on “High energy photon collisions at the LHC

30. Workshop on “High energy photon collisions at the LHC

31. What about experiments at SOLENOIDAL TRACKER ( STAR ) ? RHIC: Relativistic Heavy Ion Collider Energy =100 GeV/nucleon Au + Au collisions Circumference = 2.4 miles Workshop on “High energy photon collisions at the LHC

32. Cross Section of electron-positron pairs accompanied by nuclear dissociation Giant Dipole Resonance Workshop on “High energy photon collisions at the LHC

33. Why do we study the reaction ? • The test of QED at high fields – are there indications that • at the available energies more than two photons are • involved in an electron-positron pair creation? • 2. Is pair production is independent of photonuclear excitation? Workshop on “High energy photon collisions at the LHC

34. No hadronic probability, computed with Woods-Saxon nuclear form factor Workshop on “High energy photon collisions at the LHC

35. Probability of mutual Coulomb nuclear excitation with breakup as a function of impact parameter G. Baur at al. Nuclear Physics A 729 (2003) 787-808 Workshop on “High energy photon collisions at the LHC

36. Kinematic restrictions at STAR experiment Rapidity: Invariant mass: Transverse momentum : Adams J. At al. Phys. Rev. A 63:031902 (2004) Workshop on “High energy photon collisions at the LHC

37. Results: Baur at al. : σ = 1.9 mb Workshop on “High energy photon collisions at the LHC

38. Adams J. At al. Phys. Rev. A 63:031902 (2004) Workshop on “High energy photon collisions at the LHC

39. Adams J. At al. Phys. Rev. A 63:031902 (2004) Workshop on “High energy photon collisions at the LHC

40. FAIR - Facility for Antiproton and Ion Research Completed in 2015 Cost : 1.2 billion Euro QED Strong Fields Ion -Matter Interactions Workshop on “High energy photon collisions at the LHC

41. CONCLUSIONS: 1. We have obtained impact parameter dependence of lepton-pair production probability by using the semi-classical two photon method. 2. At SPS and RHIC energies, Monte Carlo QED calculations agree well with the experimantal results. 3. Can we use this method to calculate the production of other particles such as mesons, heavy leptons, may be Higgs particles ? 4. Can RHIC be used to test QED? 5. Cross section for bound-free pair production is very large and this will limit the maximum Pb-Pb luminosity at the LHC. Therefore we should understand these QED effects to a high degree of accuracy. Workshop on “High energy photon collisions at the LHC