The pion and nucleon mass differences generate a very pronounced cusp in the photoproduction reaction of a single pion on the nucleon. A nonrelativistic effective field theory to describe this reaction is constructed. The approach is rigorous in the sense that it is an effective field theory with a consistent power counting scheme. Expressions for the Sand P -wave multipole amplitudes for all f...

Introduction: The functional effects of orexin-B on the calcium spikes and excitability of the neuronal soma membrane of garden snail, Helix aspersa were studied. Methods: Conventional intracellular recording, under the current clamp conditions was performed to examine the effects of orexin-B on the configuration and electrophysiological properties of calcium spikes. Results: Application o...

A compact form for the helicity amplitudes of double bremsstrahlung is presented, utilizing a recently developed method of representing free photon polarizations which produces very compact results. The application as a.polarization monitor in a colliding beam machine such as the SLC is discussed. Submitted to Physical Review D * Work supported by the Department of Energy, contract DE AC03 76SF...

We present a method to calculate directly the K-matrices for the pion electroproduction processes in the framework of chiral quark models which allows for a clean separation of the resonant amplitudes from the background. The method is applied to the calculation of the multipole amplitudes M1+, E1+, and S1+ in the ∆ channel within the Cloudy Bag Model. A good overall description is found in a b...

In this paper, we calculate the masses and mixing angles of L = 1 negative parity N ∗ resonances in an extended GBE (Goldstone-boson-exchange model) with harmonicoscillator wave functions. By using those mixing angles, we get their photoproduction amplitudes, and compare them with experimental data and the results of OPE (onepion-exchange model), OPsE (only pseudoscalar meson exchange model), a...

We compare the resonant and non-resonant contributions in various regions of phase space for the D → Kπ semileptonic transition amplitude, computed in a chiral model which incorporates the heavy quark symmetry. Remarks on the significance for experiment and for chiral perturbation theory are made. Address after September 1, 1993, Physics Department, University of California, Irvine CA 92717

We calculate twoand three-point tachyon amplitudes of the SL(2,IR)/U(1) twodimensional Euclidean black hole for spherical topologies in the continuum approach proposed by Bershadsky and Kutasov. We find an interesting relation to the tachyon scattering amplitudes of standard non-critical string theory. ⋆ † Permanent Address: Universität Bonn, Physikalisches Institut, Nussallee 1, W-5300 Bonn 1,...

The assumption of angular ordering in gluon radiation is essential to obtain quantitative results concerning gluonic behaviors. In order to prove the validity of this assumption, we have applied our momentum space flux-tube formalism to check out the angular dependences of gluon radiation. We have calculated the probability amplitudes to get new gluon, and have found that the new gluon is gener...

We demonstrate the possibility to stabilize the probability amplitude of the upper level for a single quantum two-level atom in a classical optical field with feedback control scheme.

Single W -boson production in eγ collisions with polarized beams is investigated. Helicity amplitudes for general couplings are derived and their properties are discussed. The results are applied to the Standard Model (SM) and the left-right model. In the framework of SM the updated estimates of the measurement precision of photon anomalous coupling parameters κγ , λγ at the NLC with √ see = 50...