Measurement ofγγ*→π0transition form factor at Belle

2012/11/09 by S. Uehara, Y. Watanabe, H. Nakazawa +97 · 1 voice · 2 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions

paper · doi:10.1103/physrevd.86.092007

openalex publication_date 2012/11/09 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

We report a measurement of the process \ensuremathγ\ensuremathγ^*\ensuremath→\ensuremathπ⁰ with a 759 fb^\ensuremath-1 data sample recorded with the Belle detector at the KEKB asymmetric-energy e⁺e^\ensuremath- collider. The pion transition form factor, F(Q²), is measured for the kinematical region 4 GeV²\ensuremath\lesssimQ²\ensuremath\lesssim40 GeV², where \ensuremath-Q² is the invariant-mass squared of a virtual photon. The measured values of Q²|F(Q²)| agree well with the previous measurements below Q²\ensuremath≃9 GeV² but do not exhibit the rapid growth in the higher Q² region seen in another recent measurement, which exceeds the asymptotic QCD expectation by as much as 50%.

Citations

• Measurement of theγγ*→π0transition form factor

Cited by

• Updated determination of the pion-photon transition form factor
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Discussions

• The initial valence quark assignment for the neutral pion came from the quark model, but the best direct experimental constraint on the quark content of the $\pi^0$ probably comes from its measured tw [stackexchange, 1 points]

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