Recent Achievements: read about the RFQD test at Aarhus HERE.

Yet another resonance? This one took us years to find

On August 23, we found a new resonance at 616.72 nm, which is the (36,34) - (37,33) transition. We did look for this resonance at LEAR, but we failed. The predicted wavelength by Korobov is 616.6780nm, but the experimental value is about 616.72, close to the prediction by Kino (616.7206). The width is large, suggesting that the lifetime of the daughter state (37,33) is of the order of ~ 8.9 ps.

As shown below, data taken at two different target pressures show no density shift nor broadening.

Measurement of Antiproton Rydberg constant - a record breaking precision: (August 8)

On August 8, we made a high-precision spectroscopy of the 597-nm resonance. It looks like we achieved a two/three-fold improvement in the measurement accuracy compared to LEAR. We can (maybe?) achieve a higher precision with the 372-nm resonance, which is known to have a much smaller density-shift.

1. By comparing scans taken at different days, with different settings of the etalon/grating and slightly different beam conditions, laser expansion, etc. we found the reproducibility of the resonance center is within 0.0001 nm.
2. The three scans we took at different densities lie on a single line, within the error bar of +/- 0.0001 nm.
3. Extrapolation to zero yields a value which agrees with the most recent? Korobov calculation within 0.0001 nm. However, we have to remember that the density is known to only 10% precision.
4. Therefore, we tentatively conclude that the resonance has been measured to an accuracy of +/- 0.0001 nm, a factor of three better than at LEAR.

High resolution scan of the 726-nm line revealed a hyperfine structure. An important step towards the precise determination of antiproton magnetic moment.

Yet another "T1" scan, 470-nm line: The resonace intensity vs laser firing time was measured for the 470-nm line (37,34)-(36,33). Although this measurement was already done at LEAR, the data quality is already better at AD!

372-nm line "T1" scan: It was confirmed that the initial population of (35,33) is small; the "T1" scan result clearly indicates feeding from higher-lying states. Crosses are "channel1" data and stars are "channel2" data. More discussion of understanding the sytematics of the T1 data is HERE.

NEW RESONANCE: On July 18 a new resonance, (35,33)-(34,32) was discovered at 372 nm.