Dependence on k2 of fixed pole residues in pion electroproduction

It is shown that different mechanisms leading to fixed poles in electroproduction of pions lead to a specific difference of the k²-dependence of the residues of these poles, k being the momentum transfer of the electrons.     

Absence of 2kF splitting in the diffuse scattering from Cu3Au at the (001) surface

We report a new type of short-range order correlations at the (001) surface of Cu3Au which no longer produces the 2k(F)-splitting characteristic for the bulk short-range order scattering. We present the temperature dependence of this phenomenon and a theoretical interpretation of its origin. We argue that this new surface effect is caused by a drastic change of the strain-induced interactions at the surface.     

Evaluation of the Skyrme parameter from QCD sum rules

The dimensionless parameter of the Skyrme lagrangian is evaluated by two methods. In one a combination of sum rules for the nucleon and the pion is used, in the other only baryonic sum rules. e = 5−8 and e = 5−7 is found, respectively, in agreement with the phenomenological value e = 5.45. To leading order in the operator-product expansion the analytical expression of e does not depend on the chiral-symmetry-breaking parameters.     

Hadrons with charm and beauty

Zeitschrift für Physik C Particles and Fields - By combining potential models and QCD spectral sum rules (QSSR), we discuss the spectroscopy of the $$(b\bar c)$$ mesons and of the (bcq), (ccq)...     

Surface core level shift observed on NiAl(1 1 0)

Using high resolution core level spectroscopy, a surface core level shift towards lower binding energy of −0.13 eV is determined for the 2p level of the outwardly relaxed Al surface atoms on NiAl(1 1 0). Density functional theory based calculations with inclusion of final state effects yield a value of −0.14 eV for this shift in excellent agreement with experiment. We show that the initial state approximation yields a value of +0.09 eV, i.e. the inclusion of final state relaxation effects is vital not only to obtain the correct value but even the correct sign for this shift.