Coherent π^0 photoproduction on the deuteron up to 4 GeV

The differential cross section for ^2H(γ,d)π^0 has been measured at deuteron center-of-mass angles of 90° and 136°. This work reports the first data for this reaction above a photon energy of 1 GeV, and permits a test of the apparent constituent counting rule and reduced nuclear amplitude behavior as observed in elastic ed scattering. Measurements were performed up to a photon energy of 4.0 GeV, and are in good agreement with previous lower energy measurements. Overall, the data are inconsistent with both constituent-counting rule and reduced nuclear amplitude predictions

How well do we know the neutron structure function?

We present a detailed analysis of the uncertainty in the neutron F2n structure function extracted from inclusive deuteron and proton deep-inelastic scattering data. The analysis includes experimental uncertainties as well as uncertainties associated with the deuteron wave function, nuclear smearing, and nucleon off-shell corrections. Consistently accounting for the Q^2 dependence of the data and calculations, and restricting the nuclear corrections to microscopic models of the deuteron, we find significantly smaller uncertainty in the extracted F2n/F2p ratio than in previous analyses. In addition to yielding an improved extraction of the neutron structure function, this analysis also provides an important baseline that will allow future, model-independent extractions of neutron structure to be used to examine nuclear medium effects in the the deuteron.Comment: 5 pages, 6 figure

Electromagnetic proton form factors in large NcN_{c} QCD

The electromagnetic form factors of the proton are obtained using a particular realization of QCD in the large $N_c$ limit (${QCD}_{\infty}$), which sums up the infinite number of zero-width resonances to yield an Euler's Beta function (Dual-${QCD}_{\infty}$). The form factors $F_1(q^2)$ and $F_2(q^2)$, as well as $G_M(q^2)$ agree very well with reanalyzed space-like data in the whole range of momentum transfer. In addition, the predicted ratio $\mu_p G_E/G_M$ is in good agreement with recent polarization transfer measurements at Jefferson Lab.Comment: 10 page

Race matters: whether we know it, or like it, or not: implicit racial attitudes and their effect on accounting-based, balanced scorecard performance evaluations

One of the dominant themes in critical accounting theory over the past two decades has to do with the relation between the construction of human identities and accounting discourse and practices. Though with strong antecedents in Marxist –inspired critique of ideology, genealogical studies (e.g., Miller & O’Leary, 19XX), deconstructive studies (e.g., Shearer & Arrington, 19XX), and critical-rational studies (e.g., Power & Laughlin, 19XX) are examples of different theoretical and methodological ways to probe the constructive force of accounting over human identity and subjectivity. This paper offers a fourth approach grounded in social-cognitive concerns with ways in which implicit attitudes, or more broadly tacit habits of mind, enhance our tendencies to let rationally irrelevant criteria (like race, gender, and class) influence our evaluation of others. The paper reports on the results of an empirical, lab-based study of balanced scorecard evaluations and bonus allocations where race is a treatment effect and where the well-established tenets of Implicit Association Testing (IAT) are used to reveal that there are, indeed, propensities to unwillingly let racial prejudice enter into our accounting-based evaluations of others. These tendencies are more pronounced for some dimensions of the balanced scorecard than they are for others

Vegetation Structure of Mangrove Ecosystems in Panama

Mangroves provide important habitat for terrestrial and marine wildlife. They buffer shorelines from flooding and sequester excess nutrients and pollutants in runoff before reaching rivers and oceans. Mangroves provide a wintering habitat for migratory bird species. These habitats are being rapidly lost to coastal development. This research focused on assessing the vegetation structure of mangrove ecosystems in Panama

Extraction of the Axial Nucleon Form Factor from Neutrino Experiments on Deuterium

We present new parameterizations of vector and axial nucleon form factors. We maintain an excellent descriptions of the form factors at low momentum transfers ($Q^2$), where the spatial structure of the nucleon is important, and use the Nachtman scaling variable $\xi$ to relate elastic and inelastic form factors and impose quark-hadron duality constraints at high $Q^2$ where the quark structure dominates. We use the new vector form factors to re-extract updated values of the axial form factor from \numu experiments on deuterium. We obtain an updated world average value from \numud, \numubarH and pion electroproduction experiments of $M_{A}$ = $1.014 \pm 0.014 GeV/c^2$. Our parameterizations are useful in modeling $\nu$ interactions at low energies (e.g. for \numu oscillations experiments). The predictions for high $Q^2$ can be tested in the next generation electron and \numu scattering experiments.Comment: Presented by A. Bodek at the European Physical Society Meeting, EPS2007, Manchester, England, July 2007, 4 pages, 2 figure

Neutron Structure Functions

Neutron structure functions can be extracted from proton and deuteron data and a representation of the deuteron structure. This procedure does not require DIS approximations or quark structure assumptions. We find that the results depend critically on properly accounting for the Q^2 dependence of proton and deuteron data. We interpolate the data to fixed Q^2, and extract the ratio of neutron to proton structure functions. The extracted ratio decreases with increasing x, up to x \approx 0.9, while there are no data available to constrain the behavior at larger x.Comment: 16 pages, 6 figure