Search results for "Ford"
showing 10 items of 785 documents
The pion distribution amplitude and the pion-photon transition form factor in a nonlocal chiral quark model
2014
We study the pion Distribution Amplitude (\pi DA) in the context of a nonlocal chiral quark model. The corresponding Lagrangian reproduces the phenomenological values of the pion mass and decay constant, as well as the momentum dependence of the quark propagator obtained in lattice calculations. It is found that the obtained \pi DA has two symmetric maxima, which arise from the new contributions generated by the nonlocal character of the interactions. This \pi DA is applied to leading order and next-to-leading order calculations of the pion-photon transition form factor. Implications of the results are discussed.
Form factors of radiative pion decays in nonlocal chiral quark models
2012
We study the radiative pion decay π +→e +ν eγ within nonlocal chiral quark models that include wave function renormalization. In this framework we analyze the momentum dependence of the vector form factor F V(q2) and the slope of the axial-vector form factor F A(q2) at threshold. Our results are compared with available experimental information and with the predictions given by the Nambu-Jona-Lasinio model. In addition we calculate the low energy constants δ 5 and δ 6, comparing our results with the values obtained in chiral perturbation theory.
Search for strange matter by Rutherford backscattering
1989
According to a number of suggestions, stable strange matter could exist in the form of supermassive nuclei (or 'strange nuggets')1,2. In contrast to ordinary nuclei, which contain only 'up' and 'down' quarks, a piece of strange matter should comprise a mixture of 'up', 'down' and 'strange' quarks in roughly equal proportions. Small amounts of strange matter could have survived from the early stages of the Universe1. Alternatively, strange matter might reach the Earth as a flux of strange nuggets produced in collisions of neutron stars3. Limits to the cosmic flux of strange nuggets with masses in the range from 10−4 to 250 g have been obtained in a search for light produced by the nuggets in…
Perturbative generation of a strange-quark asymmetry in the nucleon
2004
We point out that perturbative evolution in QCD at three loops generates a strange-antistrange asymmetry s(x)-sbar(x) in the nucleon's sea just from the fact that the nucleon has non-vanishing up and down quark valence densities. The recently computed three-loop splitting functions allow for an estimate of this effect. We find that a fairly sizable asymmetry may be generated. Results for analogous asymmetries in the heavy-quark sector are also presented.
Switching nuclearity and Co(II) content through stoichiometry adjustment: {Co(II)6Co(III)3} and {Co(II)Co4(III)} mixed valent complexes and a study o…
2015
We are reporting two new mixed valent Co(ii)/Co(iii) polynuclear complexes, {Co II 6 Co III 3 } and {Co II Co III 4 }, bearing different amount of Co(ii) ions in their cores, through the employment of the multidentate triethanolamine (teaH 3 ) ligand in different stoichiometric ratios. We present a complete picture of the magnetic behaviour of both complexes through a combined usage of the susceptibility, magnetization and X-band EPR data as well as broken-symmetry DFT calculations. Compound 1 shows an atypical spin-only behaviour, probably due to the presence of four and five coordinated Co(ii) sites as well as highly distorted six coordinated Co(ii) ions, promoting a high degree of orbita…
Aporocotyle mariachristinae n. sp., and A. ymakara VillalbaFernández, 1986 (Digenea: Aporocotylidae) of the pink cusk-eel, Genypterus blacodes (Ophid…
2012
Aporocotyle mariachristinae n. sp. and A. ymakara Villalba & Fernández, 1986 were collected from the bulbus arteriosus and ventral aorta of pink cusk-eels, Genypterus blacodes (Forster, 1801) from Patagonia, Argentina. A. mariachristinae n. sp. can be distinguished from all the species of Aporocotyle by the asymmetrical extension of posterior caeca (right posterior caecum longer, terminating at the area between mid-level of ovary and posterior body end; left posterior caecum shorter, terminating at the area between mid-level of cirrus sac and posterior to reproductive organs), the distribution of spines along the ventro-lateral body margins and the number of testes. The new species clearly …
Women's connective action: Analysis of the mobilization of the #ParoInternacionalDeMujeres of March 8, 2017
2020
Este artículo presenta un análisis del modo de manifestarse y de las percepciones de las/ os participantes en el #ParoInternacionalDeMujeres que tuvo lugar el 8 de marzo de 2017 en Argentina. Su hipótesis sostiene que la movilización mostró una lógica de acción conectiva híbrida. La investigación que sustenta este trabajo consistió en la realización de una encuesta en el momento y lugar de la movilización, a un total de 365 personas, con el propósito de capturar la percepción de las/os participantes y no simplemente de las/os impulsoras/es. Los datos resultantes de la encuesta se interpretaron considerando cinco dimensiones analíticas creadas a partir del concepto de acción conectiva: carác…
First measurement of the charge asymmetry in beauty-quark pair production.
2014
The difference in the angular distributions between beauty quarks and antiquarks, referred to as the charge asymmetry, is measured for the first time in b[bar over b] pair production at a hadron collider. The data used correspond to an integrated luminosity of 1.0 fb[superscript −1] collected at 7 TeV center-of-mass energy in proton-proton collisions with the LHCb detector. The measurement is performed in three regions of the invariant mass of the b[bar over b] system. The results obtained are A[b[bar over b] over C](40 105 GeV/c[superscript 2]) = 1.6 ± 1.7 ± 0.6%, where A[b[bar over b] over C] is defined as the asymmetry in the difference in rapidity between jets formed from the beauty q…
Semipermeable membrane to retain platinum atoms in the electrodeposition process of alpha spectrometry sources
1998
Abstract In earlier work alpha sources electrodeposited on stainless steel backings were analyzed by X-ray fluorescence (XRF) and Rutherford backscattering spectrometry (RBS) finding that during the electrodeposition process large quantities of platinum from the anode were deposited on the cathode surface jointly with the actinides. In the present work, a method to retain platinum atoms using an electrodeposition cell with a semipermeable membrane located between anode and cathode is proposed and tested. The XRF and RBS of alpha sources electrodeposited using this method show that there is less platinum on the stainless steel backing, thereby improving the quality of sources to be measured …
Le réalisme social américain à l'ère postmoderne : (Russell Banks, Raymond Carver, Richard Ford)
2012
His study focuses on the works of Russell Banks, Raymond Carver and Richard Ford. They started writing during the 1960s and 1970s, at a time when the self-reflexivity and metafictional play of postmodernist writers were drawing a lot of critical attention in academic circles. However, they consider themselves to be realist writers. In “A Few Words about Minimalism,” John Barth suggested that the return to realist fiction in the mid-1970s could be both a reaction against so-called “postmodernist” fiction and a symptom of the social and economic unease of the period. Indeed, Cathedral, Continental Drift and The Sportswriter describe in accurate detail the everyday lives of ordinary American m…