%0 Journal Article
%T Semileptonic decays of light quarks beyond the Standard Model
%A Cirigliano, V.
%A Jenkins, J. P.
%A Gonzalez-Alonso, M.
%J Nuclear Physics B
%D 2010
%V 830
%N 1-2
%I Elsevier Science Bv
%@ 0550-3213
%G English
%F Cirigliano_etal2010
%O ISI:000275150000003
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=497), last updated on Thu, 01 Nov 2012 20:03:56 +0000
%X We describe non-standard contributions to semileptonic processes in a model independent way in terms of in SU(2)(L) x U(1)(Y) invariant effective lagrangian at the weak scale, front which we derive the low-energy effective lagrangian governing muon and beta decays. We find that the deviation from Cabibbo universality, Delta(CKM) equivalent to vertical bar V-ud vertical bar(2) + vertical bar V-us vertical bar(2) + vertical bar V-ub vertical bar(2) – 1, receives contributions from four effective operators. The phenomenological bound Delta(CKM) = (-1 +/- 6) x 10(-4) provides strong constraints on all four operators, corresponding to art effective scale Lambda > 11 TeV (90% CL). Depending on the operator, this constraint is at the same level or better then the Z pole observables. Conversely, precision electroweak constraints alone would allow universality violations as large as Delta(CKM) = -0.01 (90% CL). An observed Delta(CKM) not equal 0 at this level Could be explained in terms of a single four-fermion operator which is relatively poorly constrained by electroweak precision measurements.
%K Semileptonic decays
%K CKM unitarity
%K Effective theory
%K Beyond the Standard Model
%R 10.1016/j.nuclphysb.2009.12.020
%U http://lanl.arxiv.org/abs/0908.1754
%U https://doi.org/10.1016/j.nuclphysb.2009.12.020
%P 95-115