# Measurements of the $B \to D^*$ Form Factors Using the Decay $\bar{B}^0 \to D^{*+}e^- \bar{\nu}_e$

Abstract : We measure the dependence of $\bar B^0 \to D^{*+}e^-\bar{\nu}_e$ on the decay angles and momentum transfer. The data sample consists of $\sim 86 \times 10^6$ $B\bar B$-pairs accumulated on the $\Upsilon(4{\rm S})$ resonance by the BABAR detector at the asymmetric $e^+ e^-$ collider PEP-II. We specify the three form factors by two ratios $R_1$ and $R_2$, and by a single parameter $\rho^2$ characterizing the polynomial representing $h_{A_1}$, the function which describes the momentum-transfer dependence of the form factor $A_1$. We determine $R_1$, $R_2$, and $\rho^2$ using an unbinned maximum likelihood fit to the full decay distribution. The results are $R_1=1.396\pm 0.060\pm 0.035\pm 0.027$, $R_2=0.885\pm 0.040\pm 0.022\pm 0.013$, and $\rho^2=1.145\pm 0.059\pm 0.030\pm 0.035$. The stated uncertainties are the statistical from the data, statistical from the size of the Monte Carlo sample and the systematic uncertainty, respectively. In addition, based on this measurement, we give an updated value for the CKM matrix element $|V_{cb}|$.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00025743
Contributor : Claudine Bombar <>
Submitted on : Tuesday, March 7, 2006 - 12:08:05 PM
Last modification on : Wednesday, September 16, 2020 - 4:23:38 PM

### Citation

B. Aubert, R. Barate, D. Boutigny, F. Couderc, Y. Karyotakis, et al.. Measurements of the $B \to D^*$ Form Factors Using the Decay $\bar{B}^0 \to D^{*+}e^- \bar{\nu}_e$. Physical Review D, American Physical Society, 2006, 74, 092004 (30 p.). ⟨10.1103/PhysRevD.74.092004⟩. ⟨in2p3-00025743⟩

Record views