New DELPHI Results from Semileptonic b, c Decays

TL;DR

This paper presents new measurements of semileptonic B-hadron decays, including branching ratios and CKM matrix elements, using innovative inclusive and double tag methods to improve precision in heavy flavor physics.

Contribution

It introduces novel inclusive and double tag techniques for measuring semileptonic decay parameters and CKM matrix elements in B-hadron decays.

Findings

Measured inclusive semileptonic branching ratios of b quarks.

Determined the CKM matrix element Vcb from differential decay widths.

Estimated the ratio Vub/Vcb using reconstructed secondary hadronic mass.

Abstract

The inclusive direct and cascade semileptonic branching ratios of the b quark were measured from a fit to the lepton momentum spectrum in the B-hadron rest frame, exploiting the charge correlation between the lepton and the heavy meson. The value of the Vcb element in the CKM quark mixing matrix was computed from the differential decay width of the process B0--> D+-* l- nu, measured as a function of the product W of the B and D* 4-velocities, using an inclusive method of D* reconstruction. A measurement of the ratio Vub/Vcb has been obtained by using the reconstructed secondary hadronic mass in semileptonic decays of B hadrons. The charm semileptonic branching ratio was measured using a double tag method based on the detection of exclusively reconstructed D mesons accompanied by a lepton in the opposite hemisphere.