We present experimental and theoretical results on photodetachment of Br(-) and F(-) in a strong infrared laser field. The observed photoelectron spectra of Br(-) exhibit a high-energy plateau along the laser polarization direction, which is identified as being due to the rescattering effect. The shape and the extension of the plateau is found to be influenced by the depletion of negative ions during the interaction with the laser pulse. Our findings represent the first observation of electron rescattering in above-threshold photodetachment of an atomic system with a short-range potential.

The uncertainty on the Argonne neutrino spectrum shown in Fig. 27(c) is incorrect. Here, we bring the same figure with the correct uncertainty as given in Ref. [19]. We note that this uncertainty includes the theoretical uncertainty from the recoil-order corrections which is roughly half as large as the uncertainty from the α-spectrum measurement [19]. The conclusions of the paper are unaffected. FIG. 27. (Color online) (a) Neutrino spectrum calculated using the E x distribution obtained in the present study neglecting recoil terms and radiative corrections. Note that the end point of the neutrino spectrum (16.96 MeV) is slightly outside the energy range chosen for the plot due to insufficient numerical precision above 16 MeV. (b) 1σ statistical and systematic uncertainties on the present neutrino spectrum. (c) Relative deviation with respect to the neutrino spectrum calculated using the Argonne E x distribution.

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We report on the first experimental observation of a new threshold behavior observed in the 5(2)G partial channel in photodetachment of K(-). It arises from the repulsive polarization interaction between the detached electron and the residual K(5(2)G) atom, which has a large negative dipole polarizability. In order to account for the observation in the K(5(2)G) channel, we have developed a semiclassical model that predicts an exponential energy dependence for the cross section. The measurements were made with collinear laser-ion beams and a resonance ionization detection scheme.