Andreas R. Maier

Femtosecond x-ray pulse length characterization at the Linac Coherent Light Source free-electron laser

Two-color, single-shot time-of-flight electron spectroscopy of atomic neon was employed at the Linac Coherent Light Source (LCLS) to measure laser-assisted Auger decay in the x-ray regime. This x-ray-optical cross-correlation technique provides a straightforward, non-invasive and on-line means of determining the duration of femtosecond (>40?fs) x-ray pulses. In combination with a theoretical model of the process based on the soft-photon approximation, we were able to obtain the LCLS pulse duration and to extract a mean value of the temporal jitter between the optical pulses from a synchronized Ti-sapphire laser and x-ray pulses from the LCLS. We find that the experimentally determined values are systematically smaller than the length of the electron bunches. Nominal electron pulse durations of 175 and 75?fs, as provided by the LCLS control system, yield x-ray pulse shapes of 120?20?fs full-width at half-maximum (FWHM) and an upper limit of 40?20?fs FWHM, respectively. Simulations of the free-electron laser agree well with the experimental results.

NLO QCD corrections to \( {W}^{+}{W}^{-} b\overline{b} \) production with leptonic decays in the light of top quark mass and asymmetry measurements

A bstractWe present the NLO QCD corrections to the processes pp and pp¯→W+W−bb¯

Frequency-shifted sources for Terahertz-driven linear electron acceleration

p\overline{p}\to {W}^{+}{W}^{-} b\overline{b}

Nucleophilic Reactivities of Primary and Secondary Amines in Acetonitrile

including leptonic decays of the W bosons. Non-resonant contributions as well as diagrams with doubly resonant and singly resonant top quark propagators are fully taken into account. We employ the narrow width approximation to perform the decays of the W bosons; spin correlations are however preserved. We also calculate observables relevant for top quark mass measurements, and study the impact of kinematical requirements and different scale choices on tt¯

Ultralow emittance electron beams from a laser-wakefield accelerator

t\overline{t}

SINBAD - A PROPOSAL FOR A DEDICATED ACCELERATOR RESEARCH FACILITY AT DESY

asymmetries.