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

Y(5S) spectroscopy at Belle

7 Jul 2012, 12:00
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 Room 220 Lattice QCD / B-Physics / CP Violation, etc -TR5&7&10

Speaker

Prof. Alexander Bondar (Novosibirsk State University (RU))

Description

We report the results of the $R_b$ scan in the region from 10750 MeV to 11020 MeV in steps of 5 MeV. The scan data were collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. This result can be used to map the shape of the $\Upsilon(10860)$ and $\Upsilon(11020)$ resonances. The search for the tetraquark candidate $Y(10900)$ is also reported. We report on the study of the hadronic transitions from the $\Upsilon(5S)$ to lower bottomonia using 121.4 fb$^{-1}$ data collected at the $\Upsilon(5S)$ resonance by the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Decays of the $\Upsilon(5S)$ to the $\Upsilon(1D)\pi^+\pi^-$ and $\Upsilon(1,2S)\eta$ final states have been observed for the first time. Recently, Belle observed the spin-singlet bottomonium states $h_b(1P)$ and $h_b(2P)$. Radiative transitions to the $\eta_b(1S)$ and $\eta_b(2S)$ are expected to account for a large fraction of the $h_b(nP)$ decays. We report on the measurement of the $\eta_b(1S)$ and $\eta_b(2S)$ parameters using these radiative transitions. We report the most precise measurement of the $\eta_b(1S)$ mass, first measurement of its width, first measurement of the $\eta_b(2S)$ mass, and first measurement of the branching fractions of the radiative transitions $h_b(nP)\rightarrow\eta_b(mS)\gamma$. Recently, Belle observed two exotic resonances $Z_b(10510)$ and $Z_b(10560)$ produced in the $\Upsilon(5S)\rightarrow Z_b^+\pi^-$ transitions and decaying into the $\Upsilon(1S)\pi^+$, $\Upsilon(2S)\pi^+$, $\Upsilon(3S)\pi^+$, $h_b(1P)\pi^+$ and $h_b(2P)\pi^+$ final states. We report on further studies of these resonances.

Primary author

Prof. Alexander Bondar (Novosibirsk State University (RU))

Presentation materials