Measurement of initial-state–final-state radiation interference in the processes e[superscript +]e[superscript -] → μ[superscript +]μ[superscript -]γ and e[superscript +]e[superscript -] → π[superscript +]π[superscript -]γ
Name
PhysRevD.92.072015.pdf
Size
1.36 MB
Format
Adobe PDF
Checksum (MD5)
217d16ac6158c874733b1a1fbcbbbb80
Author(s)
Lees, J. P.
Poireau, V.
Tisserand, V.
Grauges, E.
Palano, A.
Eigen, G.
Stugu, B.
Brown, D. N.
Kerth, L. T.
Kolomensky, Yu. G.
Date Issued
October 2015
Journal
Physical Review D
Publisher
American Physical Society
Citation
Lees, J. P., V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, B. Stugu, et al. “ Measurement of Initial-State–final-State Radiation Interference in the Processes e[superscript +]e[superscript -] → μ[superscript +]μ[superscript -]γ and e[superscript +]e[superscript -] → π[superscript +]π[superscript -]γ.” Phys. Rev. D 92, no. 7 (October 2015). © 2015 American Physical Society
Version
Final published version
Abstract
Charge asymmetry in the processes e[superscript +]e[superscript -] → μ[superscript +]μ[superscript -]γ and e[superscript +]e[superscript -] → π[superscript +]π[superscript -]γ is measured using 232 fb[superscript -1] of data collected with the BABAR detector at e[superscript +]e[superscript -] center-of-mass energies near 10.58 GeV. An observable is introduced and shown to be very robust against detector asymmetries while keeping a large sensitivity to the physical charge asymmetry that results from the interference between initial- and final-state radiation (FSR). The asymmetry is determined as a function of the invariant mass of the final-state tracks from production threshold to a few GeV/c[superscript 2]. It is compared to the expectation from QED for e[superscript +]e[superscript -] → μ[superscript +]μ[superscript -]γ, and from theoretical models for e[superscript +]e[superscript -] → π[superscript +]π[superscript -]γ. A clear interference pattern is observed in e[superscript +]e[superscript -] → π[superscript +]π[superscript -]γ, particularly in the vicinity of the f[subscript 2](1270) resonance. The inferred rate of lowest-order FSR production is consistent with the QED expectation for e[superscript +]e[superscript -] → μ[superscript +]μ[superscript -]γ, and is negligibly small for e[superscript +]e[superscript -] → π[superscript +]π[superscript -]γ.
MIT Department
Massachusetts Institute of Technology. Laboratory for Nuclear Science
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
http://dx.doi.org/10.1103/PhysRevD.92.072015
