Precision Determination of α s from Lattice QCD

We present an overview of the recent lattice determination of the QCD coupling <inline-formula> <math display="inline"> <semantics> <msub> <mi>&#945;</mi> <mi>s</mi> </msub> </semantics> </math> </inline-formula> by the ALPHA Collaboration. The computation is based on the non-perturbative determination of the <inline-formula> <math display="inline"> <semantics> <mo>&#923;</mo></semantics></math></inline-formula>-parameter of <i>N</i>_f <inline-formula> <math display="inline"> <semantics> <mrow> <mo>=</mo> <mn>3</mn> </mrow> </semantics> </math> </inline-formula> QCD, and the perturbative matching of the <i>N</i>_f <inline-formula> <math display="inline"> <semantics> <mrow> <mo>=</mo> <mn>3</mn> </mrow> </semantics> </math> </inline-formula> and <i>N</i>_f <inline-formula> <math display="inline"> <semantics> <mrow> <mo>=</mo> <mn>5</mn> </mrow> </semantics> </math> </inline-formula> theories. The final result: <inline-formula> <math display="inline"> <semantics> <mrow> <msub> <mi>&#945;</mi> <mi>s</mi> </msub> <mrow> <mo>(</mo> <msub> <mi>m</mi> <mi>Z</mi> </msub> <mo>)</mo> </mrow> <mo>=</mo> <mn>0.11852</mn> <mrow> <mo>(</mo> <mn>84</mn> <mo>)</mo> </mrow> </mrow> </semantics> </math> </inline-formula>, reaches sub-percent accuracy.

Abstract licence: CC BY

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