# The 2009 Europhysics Conference on High Energy Physics

Jul 16 – 22, 2009
Kraków, Poland
Europe/Warsaw timezone

## Exclusive semileptonic b -> c decays at Belle

Jul 17, 2009, 4:30 PM
20m
Large (Kraków, Poland)

### Large

#### Kraków, Poland

The Auditorium Maximum of the Jagiellonian University 33 Krupnicza Street 31-123 Kraków
Flavour Physics

### Speaker

Wolfgang Dungel (Institute for high energy physics, Austrian academy of Sciences)

### Description

Measurement of the decay $B^0 \to D^{*-} l^+ \nu$ We present measurements of the branching fraction and of the HQET form factors $\rho^2$, $R_1$ and $R_2$ for the decay $B^0 \to D^{*-} l^+ \nu$ using untagged $\Upsilon(4S) \to B \bar B$ events. The Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ is extracted and a test of the form factor parametrization is presented. The results are based on a large data sample recorded by the Belle detector at the KEKB $e^+ e^-$ collider. Measurement of the decay $B^+ \to \bar{D}^{*0} l^+ \nu$ The measurement of the decay $B^+ \to \bar{D}^{*0} l^+ \nu$ does not rely on charged slow pion reconstruction and thus allows us to cross-check measurements of $B^0 \to D^{*-} l^+ \nu$. We present measurements of the branching fraction and of the HQET form factors $\rho^2$, $R_1$ and $R_2$ using $\Upsilon(4S) \to B \bar B$ events. The Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ is extracted. The results are based on a data sample recorded by the Belle detector at the KEKB $e^+ e^-$ collider. Measurement of $B \to D^{(*)} \tau \nu$ using hadronic tag We present a measurement of $B \to D^* \tau \nu$ and $B \to D \tau \nu$ decays using a large data sample collected near the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider. Events are tagged by fully reconstructing one of the $B$ mesons in hadronic modes. Constraints on theoretical models with a charged Higgs boson are discussed. Studies of $B^+ \to \bar{D}^{(*)0} \tau^+ \nu$ with inclusive reconstruction of the accompanying $B$ meson We present studies of $B^+ \to \bar{D}^{*0} \tau^+ \nu$ and $B^+ \to \bar{D}^0 \tau^+ \nu$ decays using a large data sample collected with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$ collider. The events are tagged by inclusively reconstructing the accompanying $B$ meson. Measurements of branching fractions and distributions characterizing signal decays are presented.

### Primary author

Wolfgang Dungel (Institute for high energy physics, Austrian academy of Sciences)

 Slides