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Bremsstrahlung*

B. Kämpfer. Research Center Dresden-Rossendorf Technical University Dresden. Bremsstrahlung*. 1. Hadron masses 2. If we would have a theory 3. Modelling, parametrizing, guessing. * braking radiation, free-free radiation,

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Bremsstrahlung*

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  1. B. Kämpfer Research Center Dresden-Rossendorf Technical University Dresden Bremsstrahlung* 1. Hadron masses 2. If we would have a theory 3. Modelling, parametrizing, guessing * braking radiation, free-free radiation, * discovered by Nikola Tesla during high frequency research between 1888 and 1897 * with L. P. Kaptari + Gy. Wolf & H.W. Barz

  2. Hadrons = Excitations of QCD Ground State Stark Zeeman QCD ground state (vacuum) n,T

  3. Hadron Masses (Facts) hadron masses = strong interaction energy non-perturbative regime: QCD condensates / chiral symmetry Dilute Gas Approx.

  4. Hadron Masses (Visions) SU(3): numerically small Weise: enhancement via chiral gap hypothesis pot. important Hadron Masses (Facts, contd) QCD SR: Poles of propagators with V quantum numbers QCD lattice:

  5. HADES NA50 Gallmeister et al. `01 T = 170 MeV data: Agakishev et al. PRL `07 BUU: Barz et al. `06/optim. C(2AGeV) + C T = 108 MeV

  6. DLS Puzzle Solved by Bremsstrahlung? (known since 111 years) Barz et al. Bratkovskaya, Cassing C(1 AGeV) + C C(1 AGeV) + C C(1 AGeV) + C M [GeV] 1997: bremsstrahlung ... contribution was found to be small 2007: DLS puzzle... may be solved when incorporating a stronger bremsstr. contribution Aichelin 2008: differing #(NN) vs. sqrt(s) in different models

  7. If we had a Theory, e.g. QED naive (standard perturbative) QED 1. Scattering problem in vacuum: Gauge Invariance 2. In medium (LPM effect): strong modifications by multiple scatterings + destruct. interference No Brain – No Pain 3. No theory: modelling, parameterizing, guessing

  8. Virtual Bremsstrahlung N N S e+ e- N N OBE approx.: NN: np: Kroll-Ruderman

  9. NNM

  10. Effective Models at Work confirmed by ANKE confirmed by ANKE

  11. ISI + FSI Jost function formalism (important at kinematical limit of e+ e- mass) N N M Form Factors and Gauge Invariance check numerically gauge inv.

  12. bremsstr. (N only) Delta total constants „adjusted“ to Shyam-Mosel results: KK  SM(4 pi)  DLS

  13. no new parameters very different w/o contact term

  14. Bremsstrahlung only

  15. Contact term may be decisive: e.g. Compton scatt. 1. QED 2. scalar QED + = 0 (Coulomb gauge)

  16. Contact Terms may be Large contact

  17. VMD N only w/ Delta danger: double counting

  18. question: output = input? Bethe-Salpeter amplitude with same OBE kernel:

  19. x = 0.45 x = 0.50 x = 0.55

  20. factorization works: w/ VDM sub-threshold production:

  21. Spectator Distribution 1.25 1.90 3.50 HADES: data for pp and pn at the same energy are at our disposal pn/pp is not described

  22. Conclusions • Unambigious interpretation • of HADES (e+e-) data is challenging • Careful tests of elementary channels in NN • Careful test of elementary channels in pA • Careful tests of elementary channels in AA • May be bremsstrahlung solves DLS puzzle • Identification of medium modifications • of vector mesons is still an interesting • perspective: M, pT, y spectra required • Isolating rho spectral function (as NA60)?

  23. P. Higgs: „My Life as Boson“ Vor etwa vierzig Jahren schrieb der Brite Peter Higgs (* 29. Mai 1929) an einen Studenten: "Ich habe etwas völlig Nutzloses entdeckt".

  24. BUU Transport Code propagation of broad resonances (Kadanoff-Baym  Cassing-Juchem, Leupold) C(2 AGeV) + C

  25. Elementary Cross Sections BUU: resonsonance model  no indep. cross sects. fit of many elemt. channels at once

  26. Spectral Functions

  27. Gauge Invariance

  28. QCD Sum Rules QCD condensates Landau damp. pert. term Borel 4-quark condensates (factorization fails: )  CB-TAPS constraints?

  29. 4-q cond. = order parameter of chiral symmetry?

  30. The Case of phi Meson fireball evolution for SIS18 BK, Pavlenko, Zschocke, EPJA ´03

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