2,419 research outputs found
Generalized Mathai-Quillen topological sigma models
A simple field theoretical approach to Mathai-Quillen topological field theories of maps X: M_I\rightarrow M_T from an internal space to a target space is presented. An operator that is closely related to the topological charge Q is introduced. This operator turns out to be a very convenient tool for studying the geometrical properties of the theory on the target space. As an example of applications of our formalism we compute by applying our formulas the action and Q-variations of the fields of two well known topological systems: Topological Quantum Mechanics and type-A topological Sigma Model
Page charge of D-branes and its behavior in topologically nontrivial B-fields
The RR Page charges for the D(2p+1)-branes with B-field in type IIB
supergravity are constructed consistently from brane source currents. The
resulting Page charges are B-independent in the nontrivial and intricate way.
It is found that in topologically trivial B-field the Page charge is conserved,
but in the topologically nontrivial B-field it is no longer to be conserved,
instead there is a jump between two Page charges defined in each patch, and we
interpret this jump as Hanany-Witten effect.Comment: 25 pages, 4 figures, typos corrected and reference adde
Recommended from our members
Oat and lipolysis: food matrix effect
Oat is rich in a wide range of phytochemicals with various physico-chemical, colloidal and interfacial properties. These characteristics are likely to influence human lipid metabolism and the subsequent effect on health following oat consumption. The aim of this work was to investigate the impact of oat materials varying in complexity on the lipolysis process. The composition, structure and digestibility of different lipid systems (emulsions, oil bodies and oil enriched in phytosterols) were determined. The surface activities of phytosterols were examined using the pendant drop technique. Differences in lipid digestibility of the oat oil emulsions and the oil bodies were clearly seen. Also, the digestion of sunflower oil was reduced proportionally to the concentration of phytosterols present. This may be due to their interfacial properties as demonstrated by the pendant drop experiments. This work highlights the importance of considering the overall structure of the system studied and not only its composition
EndCap Module Production for the ATLAS Silicon Tracker (SCT) at CERN and the University of Geneva
This note describes the infrastructure, procedure and quality assurance for the construction of approximately one third of the EndCap modules for the ATLAS Semiconductor Tracker (SCT) by groups at the University of Geneva and CERN
Study of Spin and Decay-Plane Correlations of W Bosons in the e+e- -> W+W- Process at LEP
Data collected at LEP at centre-of-mass energies \sqrt(s) = 189 - 209 GeV are
used to study correlations of the spin of W bosons using e+e- -> W+W- -> lnqq~
events. Spin correlations are favoured by data, and found to agree with the
Standard Model predictions. In addition, correlations between the W-boson decay
planes are studied in e+e- -> W+W- -> lnqq~ and e+e- -> W+W- -> qq~qq~ events.
Decay-plane correlations, consistent with zero and with the Standard Model
predictions, are measured
Ultrarelativistic sources in nonlinear electrodynamics
The fields of rapidly moving sources are studied within nonlinear
electrodynamics by boosting the fields of sources at rest. As a consequence of
the ultrarelativistic limit the delta-like electromagnetic shock waves are
found. The character of the field within the shock depends on the theory of
nonlinear electrodynamics considered. In particular, we obtain the field of an
ultrarelativistic charge in the Born-Infeld theory.Comment: 10 pages, 3 figure
Measurement of the Cross Section for Open-Beauty Production in Photon-Photon Collisions at LEP
The cross section for open-beauty production in photon-photon collisions is
measured using the whole high-energy and high-luminosity data sample collected
by the L3 detector at LEP. This corresponds to 627/pb of integrated luminosity
for electron-positron centre-of-mass energies from 189GeV to 209GeV. Events
containing b quarks are identified through their semi-leptonic decay into
electrons or muons. The e+e- -> e+e-b b~X cross section is measured within our
fiducial volume and then extrapolated to the full phase space. These results
are found to be in significant excess with respect to Monte Carlo predictions
and next-to-leading order QCD calculations
- …