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Determining $α_s$ from Measurements at $Z$: How Nature Prompts us about New Physics

M. Shifman
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Abstract

The value of $α_s (M_Z)$ emerging from the so called global fits based mainly on the data at the $Z$ peak (and assuming the standard model) is three standard deviations higher than the one stemming from the low-energy phenomenology. The corresponding value of $Λ_{\rm QCD}$ is very large, $\sim$ 500 MeV, and is incompatible with crucial features of QCD. If persists, the discrepancy should be interpreted as due to contributions to the $Z$-quark-antiquark vertices which go beyond the standard model.

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M. Shifman. 1995-01-20. Determining $α_s$ from Measurements at $Z$: How Nature Prompts us about New Physics. https://doi.org/10.1142/s0217732395000648

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