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تسجيل مستخدم جديدThe magnetic moments of the proton and the antiproton
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Recent exciting progress in the preparation and manipulation of the motional quantum states of a single trapped proton enabled the first direct detection of the particles spin state. Based on this success the proton magnetic moment $mu_p$ was measured with ppm precision in a Penning trap with a superimposed magnetic field inhomogeneity. An improvement by an additional factor of 1000 in precision is possible by application of the so-called double Penning trap technique. In a recent paper we reported the first demonstration of this method with a single trapped proton, which is a major step towards the first direct high-precision measurement of $mu_p$. The techniques required for the proton can be directly applied to measure the antiproton magnetic moment $mu_{bar{p}}$. An improvement in precision of $mu_{bar{p}}$ by more than three orders of magnitude becomes possible, which will provide one of the most sensitive tests of CPT invariance. To achieve this research goal we are currently setting up the Baryon Antibaryon Symmetry Experiment (BASE) at the antiproton decelerator (AD) of CERN.
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The spin-magnetic moment of the proton $mu_p$ is a fundamental property of this particle. So far $mu_p$ has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precisi
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DeclareRobustCommand{pbar}{HepAntiParticle{p}{}{}xspace} DeclareRobustCommand{p}{HepParticle{p}{}{}xspace} DeclareRobustCommand{mup}{$mu_{p}${}{}xspace} DeclareRobustCommand{mupbar}{$mu_{pbar}${}{}xspace} DeclareRobustCommand{muN}{$mu_N${}{}xspace
For the first time a single trapped pbar is used to measure the pbar magnetic moment ${bmmu}_{pbar}$. The moment ${bmmu}_{pbar} = mu_{pbar} {bm S}/(hbar/2)$ is given in terms of its spin ${bm S}$ and the nuclear magneton (muN) by $mu_{pbar}/mu_N = -2.792,845 pm 0.000,012$. The 4.4 parts per million (ppm) uncertainty is 680 times smaller than previously realized. Comparing to the proton moment measured using the same method and trap electrodes gives $mu_{pbar}/mu_p = -1.000,000 pm 0.000,005$ to 5 ppm, for a proton moment ${bm{mu}}_{p} = mu_{p} {bm S}/(hbar/2)$, consistent with the prediction of the CPT theorem.
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