10,535,530 research outputs found
Improvement of the Theta+ width estimation method on the Light Cone
Recently, Diakonov and Petrov have suggested a formalism in the Relativistic
Mean Field Approximation allowing one to derive the 3-, 5-, 7-,... quark
wavefunctions for the octet, decuplet and antidecuplet. They have used this
formalism and many strong approximations in order to estimate the exotic Theta+
width. The latter has been estimated to ~4 MeV. Besides they obtained that the
5-quark component of the nucleon is about 50% of its 3-quark component meaning
that relativistic effects are not small. We have improved the technique by
taking into account some relativistic corrections and considering the
previously neglected 5-quark exchange diagrams. We also have computed all
nucleon axial charges. It turns out that exchange diagrams affect very little
Diakonov's and Petrov's results while relativistic corrections reduce the
Theta+ width to ~2 MeV and the 5- to 3-quark component of the nucleon ratio to
30%.Comment: 28 pages, 15 figures; typo corrected and few comments adde
Shear viscosity in magnetized neutron star crust
The electron shear viscosity due to Coulomb scattering of degenerate
electrons by atomic nuclei throughout a magnetized neutron star crust is
calculated. The theory is based on the shear viscosity coefficient calculated
neglecting magnetic fields but taking into account gaseous, liquid and solid
states of atomic nuclei, multiphonon scattering processes, and finite sizes of
the nuclei albeit neglecting the effects of electron band structure. The
effects of strong magnetic fields are included in the relaxation time
approximation with the effective electron relaxation time taken from the
field-free theory. The viscosity in a magnetized matter is described by five
shear viscosity coefficients. They are calculated and their dependence on the
magnetic field and other parameters of dense matter is analyzed. Possible
applications and open problems are outlined.Comment: 6 pages, 3 figures, EPL, accepte
Developments in space power components for power management and distribution
Advanced power electronic components development for space applications is discussed. The components described include transformers, inductors, semiconductor devices such as transistors and diodes, remote power controllers, and transmission lines
Interrelationships between interstellar and interplanetary grains
The relationship between solar system dust (SSD) and interstellar dust particles (ISMD) is being reconsidered because of the discovery of isotopic anomalies in meteorites. Meteoritic, circumstellar/meteoritic, interstellar/meteoritic, planetary, and cometary data are reviewed
Theory, reality, and possibilities for a digital/communicative socialist network society
Digital capitalism is guided by the organising principles of digital automation, information processing, and communication. It rests on the consolidation of relations of exploitation of digital labour based on flexibility and generating precarity. It makes profit from user data under conditions of surveillance. What would an alternative paradigm look like? This paper aims to sketch a possible socialist society resting on digital technology but organised on a different logic, namely that of autonomous production, leisure, and social engagement. It draws on relevant theories of the Left, evaluates them against the reality of digital capitalism, and suggests structural and user practice alternatives that can pave the way towards a digital/communicative socialism. This paper engages with the works of Czech philosopher Radovan Richta (1924-1983) and Austrian-French philosopher André Gorz (1923-2007). It shows that their ideas on the scientific and technological revolution and post-industrial socialism are highly relevant for the analysis and discussion of digital/communicative socialism
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