Limit on a right-handed admixture to the weakb→ccurrent from semileptonic decays
| Autor: | Heiko Lacker, Verena Klose, Robert Feger, Thomas Lück, Thomas Mannel |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Physics
Semileptonic decay Nuclear and High Energy Physics Particle physics High Energy Physics::Phenomenology Hadron FOS: Physical sciences Order (ring theory) Elementary particle Standard Model High Energy Physics - Phenomenology Particle decay High Energy Physics - Phenomenology (hep-ph) High Energy Physics::Experiment Energy (signal processing) Lepton |
| Zdroj: | Physical Review D. 82 |
| ISSN: | 1550-2368 1550-7998 |
| Popis: | We determine an upper bound for a possible right-handed $b{\to}c$ quark current admixture in semileptonic $\bar{B} \to X_{c} \ell^{-} \bar{\nu}$ decays from a simulateous fit to moments of the lepton-enery and hadronic-mass distribution measured as a function of the lower limit on the lepton energy, using data measured by the \babar\ detector. The right-handed admixture is parametrized by a new parameter $c_R$ as coefficient of computed moments with right-handed quark current. For the standard model part we use the prediction of the heavy-quark expansion (HQE) up to order $1/m_b^3$ and perturbative corrections and for the right-handed contribution only up to order $1/m_b^2$ and perturbative corrections. We find $\cR=0.05\asympm{+0.33}{-0.50}$ in agreement with the standard-model prediction of zero. Additionally, we give a contraint on a possible right-handed admixture from exclusive decays, which is with a value of $\cR =0.01{\pm}0.03$ more restrictive than our value from the inclusive fit. The difference in \Vcb between the inclusive and exclusive extraction is only slightly reduced when allowing for a right-handed admixture in the range of $\cR=0.01 {\pm} 0.03$. Comment: 7 pages, 3 figures, 2 tables |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|