Observation of the $\Upsilon(1^3D_J)$ Bottomonium State through Decays to $\pi^+\pi^-\Upsilon(1S)$

TL;DR

This paper reports the first observation of the ottomonium  state via its decay to  to  and pions, confirming its mass and quantum numbers with high statistical significance.

Contribution

First experimental observation of the  bottomonium state through its decay chain, providing precise mass measurement and quantum number confirmation.

Findings

Observed the J bottomonium state with 5.8 sigma significance.

Measured the mass of the J=2 state as 10164.5 MeV/c^2.

Confirmed the orbital angular momentum assignment through invariant mass analysis.

Abstract

Based on $122\times 10^6$ \ThreeS events collected with the \babar\ detector, we have observed the \OneDJ bottomonium state through the $\ThreeS\to\g\g\OneDJ\to\g\g\pip\pim\OneS$ decay chain.The significance for the $J=2$ member of the \OneDJ triplet is 5.8 standard deviations including systematic uncertainties.The mass of the $J=2$ state is determined to be $10164.5\pm0.8\,\rm{(stat.)}\pm0.5\,\rm{(syst.)}$~\mevcc.We use the $\pip\pim$ invariant mass distribution to confirm the consistency of the observed state with the orbital angular momentum assignment of the \OneDJ.