Improved π0, η, η′ transition form factors in resonance chiral theory and their $$ {a}_{\mu}^{\textrm{HLbL}} $$ contribution

• DOI: 10.1007/jhep12(2024)203
• Publication Date: 2025-01-28T03:10:42Z
• Authors: Emilio J. Estrada; Sergi Gonzàlez-Solís; Adolfo Guevara; Pablo Roig
• Keywords: Form factor (electronics)

A bstract Working with Resonance Chiral Theory, within the two resonance multiplets saturation scheme, we satisfy leading (and some subleading) chiral and asymptotic QCD constraints accurately fit simultaneously π 0 , η, η ′ transition form factors, for single double virtuality. In latter case, supplement few available measurements lattice data to ensure a faithful description. Mainly due new results doubly virtual improve over existing descriptions ′. Our evaluation of corresponding pole contributions hadronic light-by-light piece muon g − 2 read: $$ {a}_{\mu}^{\pi^0-\textrm{pole}}=\left(61.9\pm {0.6}_{-1.5}^{+2.4}\right)\times {10}^{-11} <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>a</mml:mi> <mml:mi>μ</mml:mi> <mml:mrow> <mml:msup> <mml:mi>π</mml:mi> <mml:mn>0</mml:mn> </mml:msup> <mml:mo>−</mml:mo> <mml:mtext>pole</mml:mtext> </mml:mrow> </mml:msubsup> <mml:mo>=</mml:mo> <mml:mfenced> <mml:mn>61.9</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.6</mml:mn> <mml:mn>1.5</mml:mn> <mml:mo>+</mml:mo> <mml:mn>2.4</mml:mn> </mml:mfenced> <mml:mo>×</mml:mo> <mml:mn>10</mml:mn> <mml:mn>11</mml:mn> </mml:math> {a}_{\mu}^{\eta -\textrm{pole}}=\left(15.2\pm {0.5}_{-0.8}^{+1.1}\right)\times <mml:mi>η</mml:mi> <mml:mn>15.2</mml:mn> <mml:mn>0.5</mml:mn> <mml:mn>0.8</mml:mn> <mml:mn>1.1</mml:mn> {a}_{\mu}^{\eta^{\prime }-\textrm{pole}}=\left(14.2\pm {0.7}_{-0.9}^{+1.4}\right)\times <mml:mo>′</mml:mo> <mml:mn>14.2</mml:mn> <mml:mn>0.7</mml:mn> <mml:mn>0.9</mml:mn> <mml:mn>1.4</mml:mn> total {a}_{\mu}^{\pi^0+\eta +{\eta}^{\prime }-\textrm{pole}}=\left(91.3\pm {1.0}_{-1.9}^{+3.0}\right)\times <mml:mn>91.3</mml:mn> <mml:mn>1.0</mml:mn> <mml:mn>1.9</mml:mn> <mml:mn>3.0</mml:mn> where first second errors are statistical systematic uncertainties, respectively.