# ICHEP2018 SEOUL

Jul 4 – 11, 2018
COEX, SEOUL
Asia/Seoul timezone

## Study of radiative decays of the $\Upsilon(1S)$ and of three-body decays of the $J/\psi$

Jul 5, 2018, 2:35 PM
15m
101 (COEX, Seoul)

### 101

#### COEX, Seoul

Parallel Strong Interactions and Hadron Physics

### Speaker

Nicolas Arnaud (LAL (CNRS/IN2P3 and Université Paris-Sud))

### Description

We report on recent studies of quarkonium decays performed with the data collected by the BaBar experiment at the PEP-II $e^+e^-$ collider.
In particular, we use the entire BaBar dataset to study the reaction $e^+ e^- \to \gamma_{ISR} J/\psi$, with $J/\psi \to \pi^+ \pi^- \pi^0$, $J/\psi \to K^+ K^- \pi^0$, or $J/\psi \to K_S K^\pm \pi^\mp$, and the photon $\gamma_{ISR}$ is produced via Initial-State-Radiation. We measure the relative $J/\psi$ branching fractions and perform a Dalitz plot analysis of each $J/\psi$ decay mode using an isobar model and a Veneziano model.
We also present a study of the radiative decays of the $\Upsilon(1S)$ to $\pi^+\pi^-\gamma$ and $K^+K^-\gamma$ final states, performed on the data samples collected at the peak of the $\Upsilon(2S)$ and $\Upsilon(3S)$ resonances. The $\Upsilon(1S)$ is reconstructed from the decay chains $\Upsilon(nS) \to \pi^+\pi^-\Upsilon(1S)$, with $n=2,3$. Branching fractions measurements and spin-parity analysis are reported for the $\Upsilon(1S)$ radiative decays to intermediate resonances observed in the $\pi^+\pi^-$ and $K^+K^-$ mass spectra.

### Primary authors

Fabio Anulli (Sapienza Universita e INFN, Roma I (IT)) Nicolas Arnaud (LAL (CNRS/IN2P3 and Université Paris-Sud))