Light-by-light contribution to the muon <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>g</mml:mi> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> </mml:math> within the nonlocal chiral quark model with vector and axial-vecto

The hadronic light-by-light contribution to the muon anomalous magnetic moment is calculated in the framework of a nonlocal quark model with scalar-pseudoscalar and vector–axial-vector channels. The effect of the dressing of internal photons by vector mesons is found to be tiny. As a result, the contribution from the nonstrange quark loop is <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msubsup> <a:mi>a</a:mi> <a:mi>μ</a:mi> <a:mrow> <a:mi>HLbL</a:mi> <a:mo>,</a:mo> <a:mi>Loop</a:mi> </a:mrow> </a:msubsup> <a:mo>=</a:mo> <a:mrow> <a:mo stretchy="false">(</a:mo> <a:mn>93</a:mn> <a:mo>±</a:mo> <a:mn>9.9</a:mn> <a:mo stretchy="false">)</a:mo> </a:mrow> <a:mo>×</a:mo> <a:msup> <a:mn>10</a:mn> <a:mrow> <a:mo>−</a:mo> <a:mn>11</a:mn> </a:mrow> </a:msup> </a:math> . The total value, including meson exchanges and the contribution of strange particles, is <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msubsup> <e:mi>a</e:mi> <e:mi>μ</e:mi> <e:mtext>HLbL</e:mtext> </e:msubsup> <e:mo>=</e:mo> <e:mrow> <e:mo stretchy="false">(</e:mo> <e:mn>154</e:mn> <e:mo>±</e:mo> <e:mn>12.4</e:mn> <e:mo stretchy="false">)</e:mo> </e:mrow> <e:mo>×</e:mo> <e:msup> <e:mn>10</e:mn> <e:mrow> <e:mo>−</e:mo> <e:mn>11</e:mn> </e:mrow> </e:msup> </e:math> .