The Muon Anomalous Magnetic Moment and the Pion Polarizability
We compute the charged pion loop contribution to the muon anomalous magnetic moment ɑ_µ, taking into account the effect of the charged pion polarizability, (ɑ_1 - β_1)_π^+. We evaluate this contribution using two different models that are consistent with the requirements of chiral symmetry in the low-momentum regime and perturbative quantum chromodynamics in the asymptotic region. The result increases the disagreement between the present experimental value for ɑ_µ and the theoretical, Standard Model prediction by as much as ~ 60 x 10^(-11), depending on the value of (ɑ_1 - β_1)_π^+ and the choice of the model. The planned determination of (ɑ_1 - β_1)_π^+ at Jefferson Laboratory will eliminate the dominant parametric error, leaving a theoretical model uncertainty commensurate with the error expected from planned Fermilab measurement of a_µ.
Additional Information© 2014 Published by Elsevier B.V. This is an open access article under the CC BY license. Funded by SCOAP3. Received 4 April 2014; Received in revised form 13 August 2014; Accepted 3 September 2014; Available online 6 September 2014. We thank V. Cirigliano, J. Donoghue, B. Holstein, and R. Miski-men for useful conversations; J. Bijnens for providing input on the NLO/cut-off evaluation; and D. Hertzog and D. Kawall for critical reading of this manuscript. The work is partially supported by U.S. Department of Energy contracts DE-FG02-92-ER40701 (KTE) and DE-FG02-08ER41531 and DE-SC0011095 (MJRM) and the Wisconsin Alumni Research Foundation (MJRM).
Published - 1-s2.0-S037026931400656X-main.pdf
Submitted - 1309.2225v1.pdf