Darmstadt 2016 – wissenschaftliches Programm
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PV: Plenarvorträge
PV VII
PV VII: Plenarvortrag
Freitag, 18. März 2016, 09:00–09:45, S1/01 A1
High-precision comparison of the antiproton-to-proton charge-to-mass ratio — •Christian Smorra for the Baryon Antibaryon Symmetry Experiment collaboration — CERN, 1211 Geneva 23, Switzerland — Ulmer Initiative Research Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
Invariance under the combined charge, parity and time-reversal (CPT) symmetry is the most fundamental symmetry of the Standard Model. As consequence, particles and their conjugate antiparticles have identical masses, lifetimes, and charges and magnetic moments of opposite sign. This allows to test CPT invariance by high-precision measurements of these fundamental properties.
In this talk, I will present our recent charge-to-mass ratio comparison of the proton and the antiproton. The measurement was carried out at the Baryon Antibaryon Symmetry Experiment (BASE) located at CERN’s Antiproton Decelerator. To this end, the cyclotron frequencies of a single antiproton and a negative hydrogen ion as a proxy for the proton are compared by placing them alternately in the same magnetic field. Therefore, we developed a fast adiabatic shuttling technique, which allows to exchange particles non-destructively and 50 times faster than in previous experiements. From 6500 cyclotron frequency ratio measurements we obtain a fractional difference of (q/m)p/(q/m)p-1 = -1(69)· 10−12. This tests the standard model with an energy resolution of 8· 10−18 eV. In the next step we are aiming to measure the antiproton magnetic moment with a fractional precision of 10−9. The progress towards this measurement will also be reported.