We use recent neutrino dimuon production data combined with a global deep-inelastic parton fit to construct a new parton set, NNPDF1.2, which includes a determination of the strange and antistrange distributions of the nucleon. The result is characterized by a faithful estimation of uncertainties thanks to the use of the NNPDF methodology, and is free of model or theoretical assumptions other than the use of NLO perturbative QCD and exact sum rules. Better control of the uncertainties of the strange and antistrange parton distributions allows us to reassess the determination of electroweak parameters from the NuTeV dimuon data. We perform a direct determination of the |Vcd| and |Vcs| CKM matrix elements, obtaining central values in agreement with the current global CKM fit: specifically we find |Vcd|=0.244±0.019 and |Vcs|=0.96±0.07. Our result for |Vcs| is more precise than any previous direct determination. We also reassess the uncertainty on the NuTeV determination of sin2θW through the Paschos–Wolfenstein relation: we find that the very large uncertainties in the strange valence momentum fraction are sufficient to bring the NuTeV result into complete agreement with the results from precision electroweak data.

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering / R. D. Ball, L. Del Debbio, S. Forte, A. Guffanti, J. I. Latorre, A. Piccione, J. Rojo, M. Ubiali. - In: NUCLEAR PHYSICS. B. - ISSN 0550-3213. - 823:1/2(2009), pp. 195-233.

Precision determination of electroweak parameters and the strange content of the proton from neutrino deep-inelastic scattering

S. Forte;A. Piccione;J. Rojo
Penultimo
;
2009

Abstract

We use recent neutrino dimuon production data combined with a global deep-inelastic parton fit to construct a new parton set, NNPDF1.2, which includes a determination of the strange and antistrange distributions of the nucleon. The result is characterized by a faithful estimation of uncertainties thanks to the use of the NNPDF methodology, and is free of model or theoretical assumptions other than the use of NLO perturbative QCD and exact sum rules. Better control of the uncertainties of the strange and antistrange parton distributions allows us to reassess the determination of electroweak parameters from the NuTeV dimuon data. We perform a direct determination of the |Vcd| and |Vcs| CKM matrix elements, obtaining central values in agreement with the current global CKM fit: specifically we find |Vcd|=0.244±0.019 and |Vcs|=0.96±0.07. Our result for |Vcs| is more precise than any previous direct determination. We also reassess the uncertainty on the NuTeV determination of sin2θW through the Paschos–Wolfenstein relation: we find that the very large uncertainties in the strange valence momentum fraction are sufficient to bring the NuTeV result into complete agreement with the results from precision electroweak data.
Settore FIS/02 - Fisica Teorica, Modelli e Metodi Matematici
Settore FIS/04 - Fisica Nucleare e Subnucleare
2009
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/72281
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