Analytic Estimates of the QCD Corrections to Neutrino-Nucleus Scattering

We study the QCD corrections to neutrino deep-inelastic scattering on a nucleus, and analytically estimate their size. For an isoscalar target, we show that the dominant QCD corrections to the ratio of the neutral- to charged-current events are suppressed by sin^4 theta_W, where theta_W is the weak mixing angle. We then discuss the implications for the NuTeV determination of sin^2 theta_W.Comment: 16 pages, Late

Non-perturbative structure of the polarized nucleon sea

We investigate the flavour and quark-antiquark structure of the polarized nucleon by calculating the parton distribution functions of the nucleon sea using the meson cloud model. We find that the SU(2) flavor symmetry in the light antiquark sea and quark-antiquark symmetry in the strange quark sea are broken, {\it i.e.} \Delta\ubar < \Delta \dbar and \Delta s < \Delta \sbar. The polarization of the strange sea is found to be positive, which is in contradiction to previous analyses. We predict a much larger quark-antiquark asymmetry in the polarized strange quark sea than that in the unpolarized strange quark sea. Our results for both polarized light quark sea and polarized strange quark sea are consistent with the recent HERMES data.Comment: RevTex, 17 pages plus 8 PS figure

The supersymmetric interpretation of the EGRET excess of diffuse Galactic gamma rays

Recently it was shown that the excess of diffuse Galactic gamma rays above 1 GeV traces the Dark Matter halo, as proven by reconstructing the peculiar shape of the rotation curve of our Galaxy from the gamma ray excess. This can be interpreted as a Dark Matter annihilation signal. In this paper we investigate if this interpretation is consistent with Supersymmetry. It is found that the EGRET excess combined with all electroweak constraints is fully consistent with the minimal mSUGRA model for scalars in the TeV range and gauginos below 500 GeV.Comment: 11 pages, 6 figures, extended version with more figures, as accepted for publication in Phys. Letters

A gobal fit to the anomalous magnetic moment, b->s gamma and Higgs limits in the constrained MSSM

New data on the anomalous magnetic moment a_mu of the muon together with the b->s gamma decay rate are considered within the supergravity inspired constrained minimal supersymmetric model. We perform a global statistical chi^2 analysis of these data and show that the allowed region of parameter space is bounded from below by the Higgs limit, which depends on the trilinear coupling and from above by the anomalous magnetic moment a_mu. The newest b->s gamma data deviate 1.7 sigma from recent SM calculations and prefer a similar parameter region as the 2.6 sigma deviation from a_mu.Comment: 12 pages, 7 figs. Refs. update

Constraints on Supersymmetry from Relic Density compared with future Higgs Searches at the LHC

Among the theories beyond the Standard Model (SM) of particle physics Supersymmetry (SUSY) provides an excellent dark matter (DM) candidate, the neutralino. One clear prediction of cosmology is the annihilation cross section of DM particles, assuming them to be a thermal relic from the early universe. In most of the parameter space of Supersymmetry the annihilation cross section is too small compared with the prediction of cosmology. However, for large values of the tan beta parameter the annihilation through s-channel pseudoscalar Higgs exchange yields the correct relic density in practically the whole range of possible SUSY masses up to the few TeV range. The required values of tan beta are typically around 50, i.e. of the order of top and bottom mass ratio, which happens to be also the range allowing for Yukawa unification in a Grand Unified Theory with gauge coupling unification. For such large values of tan beta the associated production of the heavier Higgses, which is enhanced by tan beta squared, becomes three orders of magnitude larger than the production of a simlar SM-like Higgs and could be observable as one of the first hints of new physics at the LHC.Comment: 12 pages, 5 figures, Published version in Phys. Lett. B with updated references and minor correction

Acquisition of motion events in L2 Spanish by German, French and Italian speakers

This article explores the second language acquisition of motion events, with particular regard to cross-linguistic influence between first and second languages. Oral narratives in Spanish as a second language by native speakers of French, German and Italian are compared, together with narratives by native Spanish speakers. Previous analysis on the expression of motion events in these languages showed that Romance languages do not always follow the same pattern; for example, Italian tends to express the component of Path more frequently than French and Spanish. The results of the present study highlight evidence of intra-typological differences, even between languages that are genetically very close. These differences seem to lead speakers to produce cases of conceptual transfer into their second language, Spanish, even when their first language is another Romance language

Light-flavor sea-quark distributions in the nucleon in the SU(3) chiral quark soliton model (I) -- phenomenological predictions --

Theoretical predictions are given for the light-flavor sea-quark distributions including the strange quark ones on the basis of the flavor SU(3) version of the chiral quark soliton model. Careful account is taken here of the SU(3) symmetry breaking effects due to the mass difference between the strange and nonstrange quarks. This effective mass difference $\Delta m_s$ between the strange and nonstrange quarks is the only one parameter necessary for the flavor SU(3) generalization of the model. A particular emphasis of study is put on the {\it light-flavor sea-quark asymmetry} as exemplified by the observables $\bar{d} (x) - \bar{u} (x), \bar{d} (x) / \bar{u} (x), \Delta \bar{u} (x) - \Delta \bar{d} (x)$ as well as on the {\it particle-antiparticle asymmetry} of the strange quark distributions represented by $s (x) - \bar{s} (x), s (x) / \bar{s} (x), \Delta s (x) - \Delta \bar{s} (x)$ etc. As for the unpolarized sea-quark distributions, the predictions of the model seem qualitatively consistent with the available phenomenological information provided by the NMC data for $\bar{d} (x) - \bar{u} (x)$, the E866 data for $\bar{d} (x) / \bar{u} (x)$, the CCFR data and Barone et al.'s fit for $s (x) / \bar{s} (x)$ etc. The model is shown to give several unique predictions also for the spin-dependent sea-quark distribution, such that $\Delta s (x) \ll \Delta \bar{s}(x) \lesssim 0$ and $\Delta \bar{d}(x) < 0 < \Delta \bar{u}(x)$, although the verification of these predictions must await more elaborate experimental investigations in the near future.Comment: 36 pages, 20 EPS figures. The revised version accepted for publication in Phys. Rev. D. The title has been changed, and the body of the paper has been divided into two pieces, i.e.. the present one which discusses the main phenomenological predictions of the model and the other one which describes the detailed formulation of the flavor SU(3) chiral quark soliton model to predict light-flavor quark and antiquark distribution functions in the nucleo

Diagonalization of the neutralino mass matrix and boson-neutralino interaction

We analyze a connection between neutralino mass sign, parity and structure of the neutralino-boson interaction. Correct calculation of spin-dependent and spin-independent contributions to neutralino-nuclear scattering should consider this connection. A convenient diagonalization procedure, based on the exponetial parametrization of unitary matrix, is suggested.Comment: 21 pages, RevTex

Finite Theories and the SUSY Flavor Problem

We study a finite SU(5) grand unified model based on the non-Abelian discrete symmetry A_4. This model leads to the democratic structure of the mass matrices for the quarks and leptons. In the soft supersymmetry breaking sector, the scalar trilinear couplings are aligned and the soft scalar masses are degenerate, thus solving the SUSY flavor problem.Comment: 17 pages, LaTeX, 1 figur

Tau neutrino deep inelastic charged current interactions

The nu_mu -> nu_tau oscillation hypothesis will be tested through nu_tau production of tau in underground neutrino telescopes as well as long-baseline experiments. We provide the full QCD framework for the evaluation of tau neutrino deep inelastic charged current (CC) cross sections, including next-leading-order (NLO) corrections, charm production, tau threshold, and target mass effects in the collinear approximation. We investigate the violation of the Albright-Jarlskog relations for the structure functions F_4,5 which occur only in heavy lepton (tau) scattering. Integrated CC cross sections are evaluated naively over the full phase space and with the inclusion of DIS kinematic cuts. Uncertainties in our evaluation based on scale dependence, PDF errors and the interplay between kinematic and dynamical power corrections are discussed and/or quantified.Comment: 28 pages, 10 figure