2,273 research outputs found
Factorization breaking in high-transverse-momentum charged-hadron production at the Tevatron?
We compare the transverse momentum (p_T) distribution of inclusive
light-charged-particle production measured by the CDF Collaboration at the
Fermilab Tevatron with the theoretical prediction evaluated at next-to-leading
order in quantum chromodynamics (QCD) using fragmentation functions recently
determined through a global data fit. While, in the lower p_T range, the data
agree with the prediction within the theoretical error or slightly undershoot
it, they significantly exceed it in the upper p_T range, by several orders of
magnitude at the largest values of p_T, where perturbation theory should be
most reliable. This disagreement is too large to be remedied by introducing
additional produced particles into the calculation, and potentially challenges
the validity of the factorization theorem on which the parton model of QCD
relies. Clearly, a breakdown of the factorization theorem, being a fundamental
property of QCD, would be extremely difficult to understand.Comment: 9 pages, 5 figures; discussion extended, references added; accepted
for publication in Physical Review Letter
Distinct magnetic signatures of fractional vortex configurations in multiband superconductors
Vortices carrying fractions of a flux quantum are predicted to exist in
multiband superconductors, where vortex core can split between multiple
band-specific components of the superconducting condensate. Using the
two-component Ginzburg-Landau model, we examine such vortex configurations in a
two-band superconducting slab in parallel magnetic field. The fractional
vortices appear due to the band-selective vortex penetration caused by
different thresholds for vortex entry within each band-condensate, and
stabilize near the edges of the sample. We show that the resulting fractional
vortex configurations leave distinct fingerprints in the static measurements of
the magnetization, as well as in ac dynamic measurements of the magnetic
susceptibility, both of which can be readily used for the detection of these
fascinating vortex states in several existing multiband superconductors.Comment: 5 pages, 4 figure
Electric properties of granitic rocks
The objective of this work is to clarify the role of water content on the charge trans- port mechanisms of different granitic rocks. The mineralogical content of the rocks will also be taken into account. From the electrical point of view these materials are rather insulating porous media where charge injection creates different phenomena like build-up charges, space charge limited currents, surface effects and other behav- iors that resemble much a variety of oxides, like AlO
A new species of Oeda (Hemiptera: Membracidae: Stegaspidinae) from Madre de Dios, Peru
Determination of fragmentation functions and their application to exotic-hadron search
We discuss studies on determination of fragmentation functions and an
application to exotic-hadron search by using characteristic differences between
favored and disfavored functions. The optimum fragmentation functions are
determined for pion, kaon, and proton in the leading order (LO) and
next-to-leading order (NLO) of the running coupling constant alpha_s by global
analyses of hadron-production data in electron-positron annihilation. Various
parametrization results are much different in disfavored-quark and gluon
fragmentation functions; however, we show that they are within uncertainties of
the determined functions by using the Hessian method for uncertainty
estimation. We find that the uncertainties are especially large in the
disfavored-quark and gluon fragmentation functions. NLO improvements are
explicitly shown in the determination by comparing uncertainties of the LO and
NLO functions. Next, we propose to use differences between favored and
disfavored fragmentation functions for determining internal quark
configurations of exotic hadrons. We make a global analysis for f_0 (980) for
finding its internal configuration; however, uncertainties are too large to
specify the structure at this stage.Comment: 8 pages, LaTeX, 7 eps files, Progress of Theoretical Physics,
Supplement in press. Proceedings of New Frontiers in QCD 2010 - Exotic Hadron
Systems and Dense Matter -, Jan.18 - Mar.19, 2010, Kyoto, Japa
Tecnologias que promovem a biosseguridade na produção avícola.
bitstream/item/60179/1/CUsersPiazzonDocuments17236.pdfProjeto/Plano de Ação: 04.06.31.900-03
Regulagem e distribuição de comedouros tubulares e bebedouros pendulares em aviários convencionais.
bitstream/item/59421/1/CUsersPiazzonDocuments30.pdfProjeto: 16.00.30001-16
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