On the Interpretation of the NA51 Experiment

We study the $p-n$ Drell-Yan asymmetry, recently measured by the NA51 collaboration, and conclude that the value quoted by their experiment only sets a lower limit on the asymmetry of the proton sea. In particular, we notice that charge symmetry breaking between the proton and the neutron may produce corrections which should be taken into account.Comment: To appear in Phys. Lett.

Local Duality and Charge Symmetry Violation in Quark Distributions

We use local quark-hadron duality to calculate the nucleon structure function as seen by neutrino and muon beams. Our result indicates a possible signal of charge symmetry violation at the parton level in the very large x region.Comment: 4 pages, 2 figures. Modified version to appear on PRD. A dicussion on the experimental errors of the form factors was adde

Heavy-quark axial charges to non-leading order

We combine Witten's renormalization group with the matching conditions of Bernreuther and Wetzel to calculate at next-to-leading order the complete heavy-quark contribution to the neutral-current axial-charge measurable in neutrino-proton elastic scattering. Our results are manifestly renormalization group invariant.Comment: 5 pages, revtex styl

Dynamical symmetry breaking in the sea of the nucleon

We derive the nonanalytic chiral behavior of the flavor asymmetry d̅ -u̅ . Such behavior is a unique characteristic of Goldstone boson loops in chiral theories, including QCD, and establishes the unambiguous role played by the Goldstone boson cloud in the sea of the proton. Generalizing the results to the SU(3) sector, we show that strange chiral loops require that the s-s̅ distribution be nonzero.A. W. Thomas, W. Melnitchouk, and F. M. Steffen

A Study of Structure Functions for the Bag Beyond Leading Order

There has recently been surprising progress in understanding the spin and flavor dependence of deep inelastic structure functions in terms of the same physics needed in the simple quark models used for hadronic spectroscopy. However, the corresponding scale is usually very low, casting doubt on the use of leading order $QCD$ evolution. We show that the conclusions are not significantly altered if one goes to next-to-leading order. In particular, the excellent agreement with unpolarized and polarized valence quark distributions is retained.Comment: 15 pages + 5 figures. To appear in Prog. of Theor. Phy

Curing tinnitus with a Cochlear Implant in a patient with unilateral sudden deafness: a case report

Cochlear implantation is a routine procedure for patients with bilateral profound sensorineural hearing loss. Some reports demonstrated a suppression of tinnitus as a side-effect after implantation. We describe the case of a 55-year-old man suffering from severe right-sided tinnitus in consequence of sudden right-sided deafness. Multiple therapeutic efforts including intravenous steroids and tympanoscopy with grafting of the round window remained unsuccessful. One year after onset of symptoms right-sided cochlear implantation was performed, which resulted in a complete abolishment of tinnitus after activating the implant. Severe unilateral tinnitus after sudden deafness might represent a new indication for cochlear implantation

Charm in the Nucleon

A next-to-leading order analysis of inelastic electroproduction of charm is performed using an interpolating scheme which maps smoothly onto massless QCD evolution at large Q^2 and photon-gluon fusion at small Q^2. In contrast with earlier analyses, this scheme allows the inclusion of quark and target mass effects and heavy quark thresholds, as well as possible non-perturbative, or intrinsic, charm contributions. We find no conclusive evidence in favor of an intrinsic charm component in the nucleon, although several data points which disagree with perturbative QCD expectations will need to be checked by future experiments.Comment: 23 pages, 9 figure

A New Analysis of Charge Symmetry Violation in Parton Distributions

To date, the strongest indication of charge symmetry violation in parton distributions has been obtained by comparing the $F_2$ structure functions from CCFR neutrino data and NMC muon data. We show that in order to make precise tests of charge symmetry with the neutrino data, two conditions must be satisfied. First, the nuclear shadowing calculations must be made explicitly for neutrinos, not simply taken from muon data on nuclei. Second, the contribution of strange and charm quarks should be calculated explicitly using next-to-leading order [NLO] QCD, and the ``slow rescaling'' charm threshold correction should not be applied to the neutrino data. When these criteria are satisfied, the comparison is consistent with charge symmetry within the experimental errors and the present uncertainty in the strange quark distribution of the nucleon.Comment: 18 pages, 4 figure