bremsstrahlung* b. kämpfer research center dresden-rossendorf technical university dresden *...
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Bremsstrahlung*B. Kämpfer
Research Center Dresden-Rossendorf Technical University Dresden
* 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
1. Hadron masses2. If we would have a theory3. Modelling, parametrizing, guessing
Dilute Gas Approx.
Hadron Masses (Facts)
hadron masses = strong interaction energy
non-perturbative regime: QCD condensates / chiral symmetry
Hadron Masses (Visions)
SU(3): numerically small
pot. importantWeise: enhancement via chiral gap hypothesis
Hadron Masses (Facts, contd)
QCD SR:
QCD lattice: Poles of propagators with V quantum numbers
HADES data: Agakishev et al. PRL `07BUU: Barz et al. `06/optim.
C(2AGeV) + C
T = 108 MeV
NA50
Gallmeisteret al. `01
T = 170 MeV
DLS Puzzle Solved by Bremsstrahlung?
Barz et al. Bratkovskaya, Cassing
M [GeV]
Aichelin 2008: differing #(NN) vs. sqrt(s) in different models
C(1 AGeV) + C
1997: bremsstrahlung ... contribution was found to be small2007: DLS puzzle... may be solved when incorporating a stronger bremsstr. contribution
C(1 AGeV) + C C(1 AGeV) + C
(known since 111 years)
If we had a Theory, e.g. QEDnaive (standard perturbative) QED
2. In medium (LPM effect): strong modifications by multiple scatterings + destruct. interference
1. Scattering problem in vacuum:
Gauge Invariance
3. No theory: modelling, parameterizing, guessingNo Brain –No Pain
ISI + FSI Jost function formalism (important at kinematical limit of e+ e- mass) Form Factors and Gauge Invariance
N N
M
check numerically gauge inv.
HADES: data for pp and pn at the same energy are at our disposal
Spectator Distribution
1.25
1.90
3.50
pn/pp is not described
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)?
Vor etwa vierzig Jahren schrieb der Brite Peter Higgs (* 29. Mai 1929) an einen Studenten: "Ich habe etwas völlig Nutzloses entdeckt".
P. Higgs: „My Life as Boson“
BUU Transport Codepropagation of broad resonances
(Kadanoff-Baym Cassing-Juchem, Leupold)C(2 AGeV) + C
Elementary Cross SectionsBUU: resonsonance model no indep. cross sects. fit of many elemt. channels at once
QCD Sum Rules
4-quark condensates(factorization fails:
Borel
QCD condensates
pert. term
Landau damp.
)
CB-TAPS constraints?
BK, Pavlenko, Zschocke, EPJA ´03
The Case of phi Meson
fireball evolutionfor SIS18