Precision determination of electroweak coupling from atomic parity violation and implications for particle physics
Feb, 2009
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Abstract: (arXiv)
We carry out high-precision calculation of parity violation in cesium atom, reducing theoretical uncertainty by a factor of two compared to previous evaluations. We combine previous measurements with our calculations and extract the weak charge of the 133Cs nucleus, Q_W = -73.16(29)_exp(20)_th. The result is in agreement with the Standard Model (SM) of elementary particles. This is the most accurate to-date test of the low-energy electroweak sector of the SM. In combination with the results of high-energy collider experiments, we confirm the energy-dependence (or 'running') of the electroweak force over an energy range spanning four orders of magnitude (from ~10 MeV to ~100 GeV). Additionally, our result places constraints on a variety of new physics scenarios beyond the SM. In particular, we increase the lower limit on the masses of extra -bosons predicted by models of grand unification and string theories.- 31.15.am
- 11.30.Er
- parity: violation
- cesium: atom
- electroweak interaction: coupling constant
- energy dependence
- grand unified theory
- string model
- new physics
- Z0: mass
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