59 research outputs found
Next to Leading Order Semi-inclusive Spin Asymmetries
We have computed semi-inclusive spin asymmetries for proton and deuteron
targets including next to leading order (NLO) QCD corrections and contributions
coming from the target fragmentation region. These corrections have been
estimated using NLO fragmentation functions, parton distributions and also a
model for spin dependent fracture functions which is proposed here. We have
found that NLO corrections are small but non-negligible in a scheme where
gluons are polarised and that our estimate for target fragmentation effects
does not modify significantly charged asymmetries but affects the so called
difference asymmetries.Comment: Latex, 14 pages, 6 figures in 4 Postcript file
Fashion showcases design: perceptions of the showcase in the brazilian popular market
The present work aims to present the showcase, its relation with the building, with fashion and with the observer. The importance of this exhibition space extends from the aesthetic and communication functions to be part of a wide textile and clothing chain. This role integrates the whole cycle of creation, textiles, clothing and fashion accessories. For this article we used bibliographical references of design and fashion, as well as methodologies of photographic and ethnographic documentation, with application of focus groups. From the focus groups were identified descriptors related to emotional design. Such descriptors point to the emotions arising from memories, tastes and attitudes. These factors can lead to decisions and assist the wider knowledge of the target audience.- This work is supported by CNPq funding on the Programa Ciencias Sem Fronteiras - CSF by national funds within the scope of the project Processo no 203068/2014-9.info:eu-repo/semantics/publishedVersio
Scale Dependence of Polarized DIS Asymmetries
We compare the dependence of the polarized deep inelastic scattering
proton asymmetry, driven by the leading order Altarelli Parisi evolution
equations, to those arising from fixed order and
approximations. It is shown that the evolution effects associated with gluons,
which are not properly taken into account by the leading order approximation,
cannot be neglected in the analysis of the most recent experimental data.Comment: Latex file, (9 figures in postcript available from
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Next to leading order semi-inclusive spin asymmetries
Abstract We have computed semi-inclusive spin asymmetries for proton and deuteron targets including next to leading order (NLO) QCD corrections and contributions coming from the target fragmentation region. These corrections have been estimated using NLO fragmentation functions, parton distributions and also a model for spin dependent fracture functions which is proposed here. We have found that NLO corrections are small but non-negligible in a scheme where gluons are polarised and that our estimate for target fragmentation effects, which is in agreement with the available semi-inclusive data, does not modify significantly charged asymmetries but is non negligible for the so called difference asymmetries.Facultad de Ciencias Exacta
Physics of the Riemann Hypothesis
Physicists become acquainted with special functions early in their studies.
Consider our perennial model, the harmonic oscillator, for which we need
Hermite functions, or the Laguerre functions in quantum mechanics. Here we
choose a particular number theoretical function, the Riemann zeta function and
examine its influence in the realm of physics and also how physics may be
suggestive for the resolution of one of mathematics' most famous unconfirmed
conjectures, the Riemann Hypothesis. Does physics hold an essential key to the
solution for this more than hundred-year-old problem? In this work we examine
numerous models from different branches of physics, from classical mechanics to
statistical physics, where this function plays an integral role. We also see
how this function is related to quantum chaos and how its pole-structure
encodes when particles can undergo Bose-Einstein condensation at low
temperature. Throughout these examinations we highlight how physics can perhaps
shed light on the Riemann Hypothesis. Naturally, our aim could not be to be
comprehensive, rather we focus on the major models and aim to give an informed
starting point for the interested Reader.Comment: 27 pages, 9 figure
A quantum mechanical model of the Riemann zeros
In 1999 Berry and Keating showed that a regularization of the 1D classical
Hamiltonian H = xp gives semiclassically the smooth counting function of the
Riemann zeros. In this paper we first generalize this result by considering a
phase space delimited by two boundary functions in position and momenta, which
induce a fluctuation term in the counting of energy levels. We next quantize
the xp Hamiltonian, adding an interaction term that depends on two wave
functions associated to the classical boundaries in phase space. The general
model is solved exactly, obtaining a continuum spectrum with discrete bound
states embbeded in it. We find the boundary wave functions, associated to the
Berry-Keating regularization, for which the average Riemann zeros become
resonances. A spectral realization of the Riemann zeros is achieved exploiting
the symmetry of the model under the exchange of position and momenta which is
related to the duality symmetry of the zeta function. The boundary wave
functions, giving rise to the Riemann zeros, are found using the Riemann-Siegel
formula of the zeta function. Other Dirichlet L-functions are shown to find a
natural realization in the model.Comment: 42 pages, 12 figure
Strong, bold, and kind : Self-control and cooperation in social dilemmas
Financial support from the Swedish Research Council (Vetenskapsrådet), from Formas through the program Human Cooperation to Manage Natural Resources (COMMONS), and the Ideenfonds of the University of Munich is gratefully acknowledged.We develop a model that relates self-control to cooperation patterns in social dilemmas, and we test the model in a laboratory public goods experiment. As predicted, we find a robust association between stronger self-control and higher levels of cooperation, and the association is at its strongest when the decision maker’s risk aversion is low and the cooperation levels of others high. We interpret the pattern as evidence for the notion that individuals may experience an impulse to act in self-interest—and that cooperative behavior benefits from self-control. Free-riders differ from other contributor types only in their tendency not to have identified a self-control conflict in the first place.PostprintPeer reviewe
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