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We reevaluate the hadronic part of the electromagnetic vacuum expectation value using the standard dispersion integral approach that utilizes the hadronic cross section measured in $\ee$ experiments as input. Previous analyses are based…

High Energy Physics - Phenomenology · Physics 2009-10-28 Morris L. Swartz

We recalculate the hadronic contribution to the effective electromagnetic coupling constant $\alpha(M^2_Z)$ using quasi-analytical approximations for the cross-section of $e^{+}e^{-} \to hadrons$ proposed earlier by one of the…

High Energy Physics - Phenomenology · Physics 2011-01-25 N. V. Krasnikov , R. Rodenberg

We reevaluate the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the $Z$-boson mass. We include newest $e^+e^- \to$ hadrons cross-section data together…

High Energy Physics - Phenomenology · Physics 2020-03-19 M. Davier , A. Hoecker , B. Malaescu , Z. Zhang

We reevaluate the hadronic vacuum polarisation contributions to the muon magnetic anomaly and to the running of the electromagnetic coupling constant at the Z-boson mass. We include newest e+e- to hadrons cross-section data (among others)…

High Energy Physics - Phenomenology · Physics 2019-05-10 Michel Davier , Andreas Hoecker , Bogdan Malaescu , Zhiqing Zhang

To obtain the value of electromagnetic coupling constant at $q^2=m^2_Z$, $\bar{\alpha}$, which plays a key role in electroweak physics one has to integrate the cross-section of $e^+e^-$-annihilation into hadrons divided by $(s-m^2_Z)$ over…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. B. Nevzorov , A. V. Novikov , M. I. Vysotsky

The electromagnetic coupling constant, $\alpha$, is one of the fundamental parameters of the Standard Model (SM). Its value at the Z boson mass, $\alpha(M_Z)$, is of particular interest as it enters electroweak precision tests. When running…

High Energy Physics - Lattice · Physics 2024-01-09 Sophie Mutzel

We reevaluate the hadronic contributions to the muon magnetic anomaly, and to the running of the electromagnetic coupling constant at the Z-boson mass. We include new pi+pi- cross-section data from KLOE, all available multi-hadron data from…

High Energy Physics - Phenomenology · Physics 2011-10-27 Michel Davier , Andreas Hoecker , Bogdan Malaescu , Zhiqing Zhang

Recent evaluations of the hadronic vacuum polarization contributions to the effective fine-structure constant alpha_{em}(M_Z) are summarized and commented. A new update based on corrected CMD-2 data is presented. My new estimates are Delta…

High Energy Physics - Phenomenology · Physics 2007-05-23 F. Jegerlehner

We present an updated determination of the hadronic vacuum polarization contribution to the running of the electromagnetic coupling $\Delta\alpha_{\mathrm{had}}^{(5)}(-Q^2)$, and of the electroweak mixing angle in the space-like momentum…

This work presents a complete re-evaluation of the hadronic vacuum polarisation contributions to the anomalous magnetic moment of the muon, $a_{\mu}^{\rm had, \, VP}$ and the hadronic contributions to the effective QED coupling at the mass…

High Energy Physics - Phenomenology · Physics 2018-07-16 Alexander Keshavarzi , Daisuke Nomura , Thomas Teubner

We have reevaluated the hadronic contribution to the anomalous magnetic moment of the muon (g-2) and to the running of the QED fine structure constant alpha(s) at s=M_Z**2. We incorporated new data from hadronic tau decays, recently…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. Alemany , M. Davier , A. Hocker

We present a determination of the QCD coupling constant, $\alpha_s$, obtained by fitting lattice results for the flavour $ud$ hadronic vacuum polarisation function to continuum perturbation theory. We use $n_f=2+1$ flavours of Domain Wall…

High Energy Physics - Lattice · Physics 2018-07-09 Renwick J. Hudspith , Randy Lewis , Kim Maltman , Eigo Shintani

The hadronic vacuum-polarization contribution to the muon anomalous magnetic moment a_{mu}(hadr) and to the value of the eleectromagnetic coupling constant at q^2 = M^2_z are determined more precisely in connection with a new more exact…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. V. Geshkenbein

We reevaluate the dispersion integrals of the leading order hadronic contributions to the running of the QED fine structure constant alpha(s) at s=M_Z^2, and to the anomalous magnetic moments of the muon and the electron. Finite-energy QCD…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Davier , A. Hocker

We introduce a model independent method for the determination of the hadronic contribution to the QED running coupling, $\Delta\alpha_{\text{HAD}}(M_{Z}^{2})$, requiring no $e^+e^-$ annihilation data as input. This is achieved by…

High Energy Physics - Phenomenology · Physics 2015-06-11 S. Bodenstein , C. A. Dominguez , K. Schilcher , H. Spiesberger

The discrepancy between the Standard Model theory and experimental measurement of the muon magnetic moment anomaly, $a_{\mu}=\left(g_{\mu}-2\right)/2$, is connected to precision electroweak (EW) predictions via their common dependence on…

High Energy Physics - Phenomenology · Physics 2020-08-25 Alexander Keshavarzi , William J. Marciano , Massimo Passera , Alberto Sirlin

A QCD model with an infinite number of vector mesons suggested by one of the authors is used to derive the value of the correction $\delta\alpha_{hadr}$ for $\alpha(m_{Z}^{2})$ due to the strong interactions. The result is…

High Energy Physics - Phenomenology · Physics 2009-10-28 B. V. Geshkenbein , V. L. Morgunov

We perform a new, detailed calculation of the hadronic contributions to the running electromagnetic coupling, $\bar{\alpha}$, defined on the Z particle (91 GeV). We find for the hadronic contribution, including radiative corrections,…

High Energy Physics - Phenomenology · Physics 2009-11-07 J. F. de Troconiz , F. J. Yndurain

We compute a theoretically driven prediction for the hadronic contribution to the electromagnetic running coupling at the $Z$ scale using lattice QCD and state-of-the-art perturbative QCD. We…

High Energy Physics - Phenomenology · Physics 2023-08-11 Jens Erler , Rodolfo Ferro-Hernandez

We critically examine the evaluation of the hadronic contribution to the running of the QED coupling, $\alpha$, from $Q^2=0$ to $Q^2=M_Z^2$. Using data for $e^+e^-\to{}$hadrons we find that $\alpha(M_Z^2)^{-1} = 128.99\pm 0.06$, as compared…

High Energy Physics - Phenomenology · Physics 2009-10-28 A. D. Martin , D. Zeppenfeld
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