# ICHEP2012

Jul 4 – 11, 2012
Melbourne Convention and Exhibition Centre
Australia/Melbourne timezone
ICHEP2012 - 36th International Conference for High Energy Physics

## Charmonium and exotic particles at Belle

Jul 5, 2012, 3:15 PM
15m
Room 220 (Melbourne Convention and Exhibition Centre)

### Room 220

#### Melbourne Convention and Exhibition Centre

Melbourne Australia
Parallel Sessions Track 7. CP Violation, CKM, Rare Decays, Meson Spectroscopy

### Speaker

Dr Bruce Yabsley (University of Sydney (AU))

### Description

We present the study of narrow charmonium(-like) resonances by $\chi_{c1,c2} \gamma$ final states in $B \to \chi_{c1,c2} \gamma K$ decays at Belle. The results are based on the full $\Upsilon(4S)$ data sample corresponding to $772 \times 10^6\ B\bar B$ pairs recorded by the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We present the study of $B^{\pm} \to J/\psi\, \eta\, K^{\pm}$ decays at Belle. Along with the branching fraction measurement, we search for narrow charmonium-like resonances in the $J/\psi\, \eta$ final state. The analysis is based on the full $\Upsilon(4S)$ data set corresponding to $772 \times 10^6\ B\bar B$ pairs collected by the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. We present the results of an amplitude analysis of the decay $\bar B^0 \to J/\psi K^- \pi^+$. A search for charged charmonium-like states in the $J/\psi \pi^+$ system has been performed. The analysis is based on a 711 fb${}^{-1}$ data sample collected by the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The cross section for $e^+ e^- \to J/\psi\, \eta$ between $\sqrt{s}={}$3.8 GeV and 5.3 GeV is measured using 980 fb${}^{-1}$ of data on and off the $\Upsilon(nS)$ resonances collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. Two resonant structures at the $\psi(4040)$ and $\psi(4160)$ are observed in the $J/\psi\, \eta$ invariant mass distribution. The transition rates of $\psi(4040)$ and $\psi(4160)$ to the $J/\psi\, \eta$ final state are measured. This is the first measurement of this hadronic transition mode. No significant signals of the $Y(4008)$, $Y(4260)$, $Y(4360)$, or $Y(4660)$ are observed in the $J/\psi\, \eta$ final state. We search for a doubly charmed tetraquark ($T_{cc}$) using a large data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. Various hadronic models, which are in good agreement in the baryon and meson sectors, show different results for tetraquarks. The production of $T_{cc}$ plays a crucial role for discriminating among these models. We report preliminary results of a search for decays of an exotic state $X$ to various modes with the $\eta_c$ meson: $\eta_c \pi^+ \pi^-$, $\eta_c \omega$, $\eta_c \eta$, and $\eta_c \pi^0$. The analysis is based on a data sample of $772 \times 10^6\ B \bar B$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider.

### Primary author

Dr Bruce Yabsley (University of Sydney (AU))

 Slides