Solar-neutrino oscillations and third-flavour admixture

With one \Delta m^2 of the appropriate order of magnitude to solve the atmospheric neutrino problem, we study the resulting three-generation vacuum-oscillation fit to the solar neutrino flux. An explanation of the atmospheric neutrino composition in terms of pure \nu_\mu \to \nu_\tau oscillations is easily compatible with the well-known two-flavour oscillation solution for solar neutrinos. The allowed parameter region in the the mixing element U_{e3}, provided this is less than about 0.4. We find that the threefold maximal mixing is disfavoured

Housing prices and multiple employment nodes: is the relationship nonmonotonic?

Standard urban economic theory predicts that house prices will decline with distance from the central business district. Empirical results have been equivocal, however. Disjoints between theory and empirics may be due to a nonmonotonic relationship between house prices and access to employment arising from the negative externalities associated with proximity to multiple centres of employment. Based on data from Glasgow (Scotland), we use gravity-based measures of accessibility estimated using a flexible functional form that allows for nonmonotonicity. The results are thoroughly tested using recent advances in spatial econometrics. We find compelling evidence of a nonmonotonic effect in the accessibility measure and discuss the implications for planning and housing policy

Model-independent constraints on contact interactions from LEP2 data analysis

We derive model-independent constraints on four-fermion contact interaction-type dynamics from the published preliminary LEP2 experimental data on e^+e^- annihilation into \mu^+\mu^- and \tau^+\tau^- pairs, measured at different energies between 130 and 207 GeV. The basic observables are chosen to be the total cross section and the forward-backward asymmetry, and the analysis realistically takes into account data uncertainties and correlations among measurements at the various energies. The combination of data from different energy points plays an important role in the determination of regions allowed for the contact interaction coupling constants. In contrast to the more common one-parameter analyses, we only obtain constraints on pairs of parameters rather than limits on individual ones.Comment: 13 pages, LaTeX, including figures. v2: Included discussion of tau data, version to appear in EPJ

Sneutrino identification in dilepton events at the LHC

Heavy neutral resonances appearing in the clean Drell-Yan channel may be the first new physics to be observed at the proton-proton CERN LHC. If a new resonance is discovered at the LHC as a (narrow) peak in the dilepton invariant mass distribution, the characterization of its spin and couplings will proceed via the measurement of production rates and angular distributions of the decay products. We discuss the discrimination of a spin-0 resonance (sneutrino) predicted by supersymmetric theories with R-parity breaking against the spin-1 of Z^\prime bosons and the Randall-Sundrum graviton resonance (spin-2) with the same mass and producing the same number of events under the observed peak. To assess the region of sneutrino parameters (couplings and masses) where the spin determination can be performed to a given confidence level, we focus on the event rate and the angular distributions of the Drell-Yan leptons, in particular using the center-edge asymmetry, A_{\rm CE}. We find that although the measured event rate permits solving the above problem partially, the center-edge asymmetry, on the contrary allows to differentiate the various spins entirely with a minimal number of events around 200.Comment: 20 pages; version to appear in PR

Randall-Sundrum graviton spin determination using azimuthal angular dependence

Quantum interference of helicity amplitudes provides a powerful tool for measuring the spins of new particles. By looking at the azimuthal angular dependence of the differential cross-section in the production followed by decay of a new particle species one can determine its spin by looking at the various cosine modes. The heavy spin-2 Kaluza-Klein (KK) graviton provides a unique signature with a $\cos{(4 \phi)}$ mode. We study the feasibility of this approach to measuring the spin of the KK graviton in the Randall-Sundrum Model at the LHC.Comment: 7 pages, 6 figure

Signals of Warped Extra Dimensions at the LHC

We discuss the signatures of the spin-2 graviton excitations predicted by the Randall-Sundrum model with one warped extra dimension, in dilepton and diphoton production at LHC. By using a specific angular analysis, we assess the ranges in mass and coupling constant where such gravitons can be discriminated against competitor spin-1 and spin-0 objects, that potentially could manifest themselves in these processes with the same mass and rate of events. Depending on the value of the coupling constant to quarks and leptons, the numerical results indicate graviton identification mass ranges up to 1.1-2.4 TeV and 1.6-3.2 TeV for LHC nominal energy of 14 TeV and time-integrated luminosity of 10 and 100~${\rm fb}^{-1}$, respectively.Comment: 8 pages, Talk given at QCD@Work - International Workshop on QCD - Theory and Experiment, 20 - 23 June, 2010, Martina Franca Ital

Identification of extra neutral gauge bosons at the International Linear Collider

Heavy neutral gauge bosons, Z's, are predicted by many theoretical schemes of physics beyond the Standard Model, and intensive searches for their signatures will be performed at present and future high energy colliders. It is quite possible that Z's are heavy enough to lie beyond the discovery reach expected at the CERN Large Hadron Collider LHC, in which case only indirect signatures of Z' exchanges may occur at future colliders, through deviations of the measured cross sections from the Standard Model predictions. We here discuss in this context the foreseeable sensitivity to Z's of fermion-pair production cross sections at an e^+e^- linear collider, especially as regards the potential of distinguishing different Z' models once such deviations are observed. Specifically, we assess the discovery and identification reaches on Z' gauge bosons pertinent to the E_6, LR, ALR and SSM classes of models, that should be attained at the planned International Linear Collider (ILC). With the high experimental accuracies expected at the ILC, the discovery and the identification reaches on the Z' models under consideration could be increased substantially. In particular, the identification among the different models could be achieved for values of Z' masses in the discovery (but beyond the identification) reach of the LHC. An important role in enhancing such reaches is played by the electron (and possibly the positron) longitudinally polarized beams. Also, although the purely leptonic processes are experimentally cleaner, the measurements of c- and b-quark pair production cross sections are found to carry important, and complementary, information on these searches.Comment: 21 page

Describing Inequalities in Access to Employment and the Associated Geography of Wellbeing

This paper addresses three questions. How unequal is access to urban employment and the wellbeing associated with it? What is the monetary value consumers place on access? How does the inequality of access correspond to the geographical pattern of unemployment? A novel approach is developed using the Osland and Pryce house price model to estimate the monetary value of access welfare (MVAW)—the wellbeing associated with living a given distance from employment, taking into account the negative externalities associated with centres of employment and the complexities that arise from the existence of multiple employment centres of varying size. It is found that: MVAW is considerably more unequal than house prices or income; MVAW contributes around 13 per cent of the average value of a house; and the spatial pattern of unemployment rates is highly inelastic with respect to both MVAW and employment, suggesting no evidence of a spatial mismatch