4,622 research outputs found
Heavy Quarkonia from Classical SU(3) Yang-Mills Configurations
A generalized Cho-Faddeev-Niemi ansatz for SU(3) Yang-Mills is investigated.
The corresponding classical field equations are solved for its simplest
parametrization. From these solutions it is possible to define a confining
central non-relativistic potential used to study heavy quarkonia. The
associated spectra reproduces the experimental spectra with an error of less
than 3% for charmonium and 1% for bottomonium. Moreover, the recently
discovered new charmonium states can be accomodate in the spectra, keeping the
same level of precision. The leptonic width show good agreement with the recent
measurements. The charmonium and bottomonium E1 electromagnetic transitions
widths are computed and compared with the experimental values.Comment: 3 pages. Talk at QNP06, 5th-10th June, Madrid, Spai
Charmonium and Bottomonium from Classical SU(3) Gauge Configurations
The charmonium and bottomonium spectra computed from a potential defined from
a single gauge configuration, obtained from solving the classical field
equations, is discussed. The theoretical spectra shows good agreement with the
measured states.
A discussion of possible interpretations, within the same non-relativistic
potential model, for the new charmonia states X(3872), and
Y(4260) is performed. In particular, we give predictions for electromagnetic E1
transitions for various scenarios.Comment: Talk given at "Quark Confinement and the Hadron Spectrum VII", Ponta
Delgada, Sao Miguel, Azores, Portugal, Sept. 2-7, 200
Microwave-Assisted Extraction of Brewers' Spent Grain Arabinoxylans
Brewers´ spent grain (BSG) is a by-product from beer industry that can be exploited as a source of
arabinoxylo-oligosaccharides (AXOS) with prebiotic activity. In this study, microwave-assisted extractions were
performed during 2 min at 140-210°Cin order to evaluate the feasibility of this extraction technology for quantitative
extraction of the arabinoxylans (AX) or AXOS from BSG. The AX yield increasedwith the increase of the temperature
in the range used. The best condition of extraction of the AXwas 210 ºC during 2 min, allowing the extraction of 43%
of total AX. These AX showed structural variability which allow to define specific types of compounds for different
applications and uses depending on the extraction conditions used
Higher curvature Bianchi identities, generalized geometry, and L∞ algebras
The Bianchi identities for bosonic fluxes in supergravity can receive higher derivative quantum and string corrections, the most well known being that of Heterotic theory . Less studied are the modifications at order that may arise, for example, in the Bianchi identity for the seven-form flux of M theory compactifications. We argue that such corrections appear to be incompatible with the exceptional generalised geometry description of the lower order supergravity, and seem to imply a gauge algebra for the bosonic potentials that cannot be written in terms of an (exceptional) Courant bracket. However, we show that this algebra retains the form of an gauge field theory, which terminates at a level ten multibracket
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