Pionic atom spectroscopy in the (d,3 He) reaction at finite angles

Formation of Deeply Bound 1s Pionic States in the Pb(d,He) Reaction

Recently, deeply bound pionic states were found experimentally in (d,He) reactions on Pb. The observed spectrum showed an excellent agreement with the DWIA calculation and the dominant peak was attributed to the pionic 2p state contribution. We studied theoretically Pb(d,He) reactions within the same model, and found that it is very likely to observe the pionic 1s state as an isolated peak in t...

Subterahertz spectroscopy at He-3 temperatures

We report on the design and implementation of an instrument for spectroscopic studies of materials at sub-terahertz ~THz! frequencies at temperatures down to 340 mK. We achieved consistent operation under these rather extreme conditions by coupling a modified Martin–Puplett interferometer to a single cryogenic unit housing two independently controlled He-3 platforms: one as a sample stage and t...

Pionic Hydrogen at Psi

The measurement of the pion–nucleon scattering lengths constitutes a high–precision test of the methods of Chiral Pertubation Theory (χPT), which is the low–energy approach of QCD. The πN s–wave scattering lengths are related to the strong–interaction shift ǫ1s and width Γ1s of the s–states of the pionic hydrogen atom. ǫ1s and Γ1s are determined from the measured energies and line widths of X–r...

Absorption spectroscopy at the limit: detection of a single atom.

We investigate the sensitivity limit of absorption spectroscopy. An experiment is described in which the decrease in transmitted light intensity that is due to absorption by a single, electromagnetically confined atomic ion is observed.

Conduction channels at finite bias in single-atom gold contacts