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Title: Rescattering Effects in the Hadronic-Light-by-Light Contribution to the Anomalous Magnetic Moment of the Muon

We present a first model-independent calculation of ππ intermediate states in the hadronic-light-by-light (HLBL) contribution to the anomalous magnetic moment of the muon (g - 2) μ that goes beyond the scalar QED pion loop. To this end, we combine a recently developed dispersive description of the HLBL tensor with a partial-wave expansion and demonstrate that the known scalar-QED result is recovered after partial-wave resummation. Using dispersive fits to high-statistics data for the pion vector form factor, we provide an evaluation of the full pion box a π μ box = –15.9(2) x 10 -11. We then construct a suitable input for the γ*γ* → ππ helicity partial waves, based on a pion-pole left-hand cut and show that for the dominant charged-pion contribution, this representation is consistent with the two-loop chiral prediction and the COMPASS measurement for the pion polarizability. This allows us to reliably estimate S-wave rescattering effects to the full pion box and leads to our final estimate for the sum of these two contributions a π μ box + a ππ,π-pole μ,J=0 LHC = –24(1) x 10 -11.
 [1] ;  [2] ;  [3] ;  [4]
  1. Univ. of Bern (Switzerland). Albert Einstein Center for Fundamental Physics. Inst. for Theoretical Physics
  2. Univ. of Washington, Seattle, WA (United States). Inst. for Nuclear Theory; Univ. of California, Santa Barbara, CA (United States). Kavli Inst. for Theoretical Physics
  3. European Organization for Nuclear Research (CERN), Geneva (Switzerland). Theoretical Physics Dept.
  4. Univ. of Bonn (Germany). Helmholtz Inst. for Radiation and Nuclear Physics. Bethe Center for Theoretical Physics; Univ. of California, San Diego, CA (United States). Dept. of Physics
Publication Date:
Grant/Contract Number:
FG02-00ER41132; PHY-1125915; SFB/TR 16; SFB/TR 110; P300P2_167751; PIEF-GA-2013-622527
Published Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 118; Journal Issue: 23; Journal ID: ISSN 0031-9007
American Physical Society (APS)
Research Org:
Univ. of Washington, Seattle, WA (United States); Univ. of Bern (Switzerland); Univ. of Bonn (Germany); European Organization for Nuclear Research (CERN), Geneva (Switzerland)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26); National Science Foundation (NSF); German Research Foundation (DFG); Swiss National Science Foundation (SNSF); European Union (EU)
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; particle interactions; strong interaction; muons; photons; pions; form factors; gyromagnetic ratio; magnetic moment
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1429071