We present an analysis of exclusive charmless semileptonic B-meson decays based on 83x10(6) B (B) over bar pairs recorded with the BABAR detector at the Upsilon(4S) resonance. Using isospin symmetry, we measure branching fractions B(B-0->pi(-)l(+)nu)=(1.38 +/- 0.10 +/- 0.16 +/- 0.08)x10(-4) and B(B-0->rho(-)l(+)nu)=(2.14 +/- 0.21 +/- 0.48 +/- 0.28)x10(-4), where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties. We compare the measured distribution in q(2), the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element V-ub=(3.82 +/- 0.14 +/- 0.22 +/- 0.11(-0.52)(+0.88))x10(-3) from B ->pi l nu, where the fourth error reflects the uncertainty of the form-factor normalization.
Study of B ->pi l nu and B ->rho l nu decays and determination of vertical bar V-ub vertical bar
FERRONI, Fernando
2005-01-01
Abstract
We present an analysis of exclusive charmless semileptonic B-meson decays based on 83x10(6) B (B) over bar pairs recorded with the BABAR detector at the Upsilon(4S) resonance. Using isospin symmetry, we measure branching fractions B(B-0->pi(-)l(+)nu)=(1.38 +/- 0.10 +/- 0.16 +/- 0.08)x10(-4) and B(B-0->rho(-)l(+)nu)=(2.14 +/- 0.21 +/- 0.48 +/- 0.28)x10(-4), where the errors are statistical, experimental systematic, and due to form-factor shape uncertainties. We compare the measured distribution in q(2), the momentum-transfer squared, with theoretical predictions for the form factors from lattice QCD and light-cone sum rules, and extract the Cabibbo-Kobayashi-Maskawa (CKM) matrix element V-ub=(3.82 +/- 0.14 +/- 0.22 +/- 0.11(-0.52)(+0.88))x10(-3) from B ->pi l nu, where the fourth error reflects the uncertainty of the form-factor normalization.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
