$B$ mesons lifetime determination in fully hadronic decays




Text for the blessed web page - CDF note 7386

The CDF Collaboration

23 March 2005

Abstract:

We present the lifetime measurements of $B^+$, $B^0$ and $B_s$ mesons, performed using fully reconstructed hadronic decays collected by the SVT trigger. Due to the impact parameter cuts of the SVT trigger the proper decay time distributions of the $B$ mesons no longer follow a simply exponential decay. The bias is corrected using a Monte Carlo based approach that have to take into account for bias coming form analysis cuts also. The lifetimes are extracted using the decay modes $B^{+}\to \bar{D}^{0}\pi^{+}$, $B^{0}\to \bar{D}^{-}\pi^{+}$, $B^{0}\to \bar{D}^{-}\pi^+\pi^-\pi^{+}$, $B_s\to \bar{D}_s^-\pi^{+}$ and $B_s\to \bar{D}_s^-\pi^+\pi^-\pi^{+}$. We measure

$c\tau(B^+) = 498 \pm 8(stat) \pm 4(syst) \mu m$,
$c\tau(B^0) = 453 \pm 7(stat) \pm 4(syst) \mu m$,
$c\tau(B_s) = 479 \pm 29(stat) \pm 5(syst) \mu m$.

or

$$c\tau(B^+) = 1.66 \pm 0.03 (stat) \pm 0.01 (syst) ps,$$

$$c\tau(B^0) = 1.51 \pm 0.02 (stat) \pm 0.01 (syst) ps,$$

$$c\tau(B_s) = 1.60 \pm 0.10 (stat) \pm 0.02 (syst) ps.$$

The availability to measure lifetimes in hadronic decay modes is an important step for mixing analysis in these samples. Moreover the measurement itself is important to improve the $B_{s}$ lifetime precision, and to test the Standard Model prediction that quote the ratio between $B^{0}$ and $B_{s}$ to be no to much far from unity.