Updated electroweak measurements from neutrino-nucleon deeply inelastic scattering at CCFR

We report the results of a study of electroweak parameters from observations of neutral current {nu}N deeply inelastic scattering in the CCFR detector at the FNAL Tevatron Quadrupole Triplet neutrino beam. An improved extraction of the weak mixing angle in the on-shell renormalization scheme, incorporating additional data and with an improved technique for constraining systematic errors, is presented. Within the Standard Model, this result constrains the W mass with a precision comparable to that from direct measurements. The result is also presented in a model-independent form, as constraints on neutral current quark-neutrino couplings, to facilitate comparisons with theories outside the Standard Model. Using this result, limits on new four-fermion interactions, lepto-quarks and neutrino oscillations are presented. Prospects for a successor experiment, NuTeV (FNAL-E815), are also presented

The Strange Parton Distribution of the Nucleon: Global Analysis and Applications

The strangeness degrees of freedom in the parton structure of the nucleon are explored in the global analysis framework, using the new CTEQ6.5 implementation of the general mass perturbative QCD formalism of Collins. We systematically determine the constraining power of available hard scattering experimental data on the magnitude and shape of the strange quark and anti-quark parton distributions. We find that current data favor a distinct shape of the strange sea compared to the isoscalar non-strange sea. A new reference parton distribution set, CTEQ6.5S0, and representative sets spanning the allowed ranges of magnitude and shape of the strange distributions, are presented. Some applications to physical processes of current interest in hadron collider phenomenology are discussed.Comment: 19 pages; revised version submitted to JHE

Old and new physics interpretations of the NuTeV anomaly

We discuss whether the NuTeV anomaly can be explained, compatibly with all other data, by QCD erects (maybe, if the strange sea is asymmetric, or there is a tiny violation of isospin), new physics in propagators or couplings of the vector bosons (not really), loops of supersymmetric particles (no), dimension six operators (yes, for one specific SU(2)(L)-invariant operator), leptoquarks (not in a minimal way), extra U(1) gauge bosons (maybe: an unmixed Z' coupled to B - 3L(mu) also increases the muon g - 2 by about 10(-9) and gives a 'burst' to cosmic rays above the GZK cutoff)

Modeling power corrections to the Bjorken sum rule for the neutrino structure function F_1

Direct measurements of the the structure functions F_1^{nu p} and F_1^{nu n} at a neutrino factory would allow for an accurate extraction of alpha_s from the Q^2-dependence of the Bjorken sum rule, complementing that based on the Gross-Llewellyn-Smith sum rule for F_3. We estimate the power (1/Q^2-) corrections to the Bjorken sum rule in the instanton vacuum model. For the reduced matrix element of the flavor-nonsinglet twist-4 operator ubar_g_Gdual_gamma_gamma5_u - (u -> d) we obtain a value of 0.18 GeV^2, in good agreement with the QCD sum rule calculations of Braun and Kolesnichenko. Our result allows to reduce the theoretical error in the determination of alpha_s.Comment: 3 pages, 1 figure, uses iopart.cls. Proceedings of the 4th NuFact'02 Workshop "Neutrino Factories based on Muon Storage Rings", Imperial College, London, July 1-6, 200