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

Abstract

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.

Authors:
 [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:
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)
OSTI Identifier:
1372583
Alternate Identifier(s):
OSTI ID: 1429071
Grant/Contract Number:
FG02-00ER41132; PHY-1125915; SFB/TR 16; SFB/TR 110; P300P2_167751; PIEF-GA-2013-622527
Resource Type:
Journal Article: Published Article
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 118; Journal Issue: 23; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; particle interactions; strong interaction; muons; photons; pions; form factors; gyromagnetic ratio; magnetic moment

Citation Formats

Colangelo, Gilberto, Hoferichter, Martin, Procura, Massimiliano, and Stoffer, Peter. Rescattering Effects in the Hadronic-Light-by-Light Contribution to the Anomalous Magnetic Moment of the Muon. United States: N. p., 2017. Web. doi:10.1103/PhysRevLett.118.232001.
Colangelo, Gilberto, Hoferichter, Martin, Procura, Massimiliano, & Stoffer, Peter. Rescattering Effects in the Hadronic-Light-by-Light Contribution to the Anomalous Magnetic Moment of the Muon. United States. doi:10.1103/PhysRevLett.118.232001.
Colangelo, Gilberto, Hoferichter, Martin, Procura, Massimiliano, and Stoffer, Peter. Fri . "Rescattering Effects in the Hadronic-Light-by-Light Contribution to the Anomalous Magnetic Moment of the Muon". United States. doi:10.1103/PhysRevLett.118.232001.
@article{osti_1372583,
title = {Rescattering Effects in the Hadronic-Light-by-Light Contribution to the Anomalous Magnetic Moment of the Muon},
author = {Colangelo, Gilberto and Hoferichter, Martin and Procura, Massimiliano and Stoffer, Peter},
abstractNote = {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 aπμbox = –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 aπμbox + aππ,π-poleμ,J=0 LHC = –24(1) x 10-11.},
doi = {10.1103/PhysRevLett.118.232001},
journal = {Physical Review Letters},
number = 23,
volume = 118,
place = {United States},
year = {Fri Jun 09 00:00:00 EDT 2017},
month = {Fri Jun 09 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.118.232001

Citation Metrics:
Cited by: 5works
Citation information provided by
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  • 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 suitablemore » 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.« less
  • We discuss the hadronic light-by-light scattering contribution to the muon anomalous magnetic moment a{sub {mu}}{sup lbl}, paying particular attention to the consistent matching between the short- and the long-distance behavior of the light-by-light scattering amplitude. We argue that short-distance QCD imposes strong constraints on this amplitude overlooked in previous analyses. We find that accounting for these constraints leads to approximately 50% increase in the central value of a{sub {mu}}{sup lbl}, compared to commonly accepted estimates (see, e.g., [M. Davier, S. Eidelman, A. Hocker, and Z. Zhang, Eur. Phys. J. C 31, 503 (2003).]). The hadronic light-by-light scattering contribution becomes a{submore » {mu}}{sup lbl}=136(25)x10{sup -11}, thereby shifting the standard model prediction closer to the experimental value.« less
  • The form factor that yields the light-by-light scattering contribution to the muon anomalous magnetic moment is computed in lattice QCD+QED and QED. A non-perturbative treatment of QED is used and is checked against perturbation theory. The hadronic contribution is calculated for unphysical quark and muon masses, and only the diagram with a single quark loop is computed. Statistically significant signals are obtained. Initial results appear promising, and the prospect for a complete calculation with physical masses and controlled errors is discussed.
  • Cited by 24