Professor Amanda Cooper-Sarkar

Abstract:

The cross sections for charged and neutral current deep inelastic scattering in e ⁺ p collisions with a longitudinally polarised positron beam have been measured using the ZEUS detector at HERA. The results, based on data corresponding to an integrated luminosity of 23.8 pb ^-1 at sqrt(s) = 318   GeV, are given for both e ⁺ p charged current and neutral current deep inelastic scattering for both positive and negative values of the longitudinal polarisation of the positron beam. Single differential cross sections are presented for the kinematic region Q ² > 200   GeV ². The measured cross sections are compared to the predictions of the Standard Model. A fit to the data yields σ ^CC ( P e = - 1 ) = 7.4 ± 3.9 ( stat. ) ± 1.2 ( syst. )   pb, which is consistent within two standard deviations with the absence of right-handed charged currents in the Standard Model. © 2006 Elsevier B.V. All rights reserved.

Abstract:

The sources of the observed ultra-high energy cosmic rays must also generate ultra-high energy neutrinos. Deep inelastic scattering of these neutrinos with nucleons on Earth probe center-of-mass energies $\sqrt{s} \sim 100$ TeV, well beyond those attainable at terrestrial colliders. By comparing the rates for two classes of observable events, any departure from the benchmark (unscreened perturbative QCD) neutrino-nucleon cross-section can be constrained. Using the projected sensitivity of the Pierre Auger Observatory to quasi-horizontal showers and Earth-skimming tau neutrinos, we show that a `Super-Auger' detector can thus provide an unique probe of strong interaction dynamics.