BELLE_2017_I1610301
Measurement of the $\pi^+\pi^-$ mass Spectrum and pion helicity angle in $\Upsilon(2,3,4S)\to\Upsilon(1S)\pi^+\pi^-$ and $\Upsilon(4S)\to\Upsilon(2S)\pi^+\pi^-$ decays by the BELLE collaboration.
Measurement of the $\pi^+\pi^-$ mass Spectrum and pion helicity angle in $\Upsilon(2,3,4S)\to\Upsilon(1S)\pi^+\pi^-$ and $\Upsilon(4S)\to\Upsilon(2S)\pi^+\pi^-$ decays by the BELLE collaboration.
