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HK: Physik der Hadronen und Kerne
HK 24: Elektromagnetische und Hadronische Proben
HK 24.3: Talk
Tuesday, March 8, 2005, 14:45–15:00, TU MA001
Deuteron Electro-Disintegration at Very Low Energies — •Stefan Christlmeier and Harald W. Grießhammer — T39, Technische Universität München, D-85747 Garching
We consider the deuteron break-up 2H(e,e′p)n at very low momentum transfer (q< 100 MeV) and close to threshold in the low-energy nuclear Effective Field Theory without dynamical pions. The result is model-independent, analytic, simple, manifestly gauge-invariant and does not suffer from ambiguities in treating off-shell effects or meson-exchange currents. There are no free parameters, and the reaction is determined by simple, well-known observables on the 1%-level. Decomposing the doubly differential cross-section into the longitudinal-plus-transverse (L+T), transverse-transverse (TT) and longitudinal-transverse interference (LT) terms, we compare to a Bonn-potential calculation by Arenhövel et al. and to experimental findings at S-DALINAC. There is no space on the theory-side for the 30%-discrepancy between theory and experiment in σLT, with un-determined short-distance contributions that could affect σLT entering only at very high orders. Further observables with relevance to big-bang nucleo-synthesis are commented upon.