434 research outputs found
Phenomenology of the Electron Structure Function
Advantages of introducing the electron structure function (ESF) in electron
induced processes are demonstrated. Contrary to the photon structure function
it is directly measured in such processes. At present energies a simultaneous
analysis of both the electron and the photon structure functions gives an
important test of the experimentally applied methods. Estimates of the ESF at
currently measured momenta are given. At very high momenta contributions from
and bosons together with - interference can be observed.
Predictions for next generation of experiments are given.Comment: 6 pages, 4 figures New version, new figures adde
The 'Square Root' of the Interacting Dirac Equation
The 'square root' of the interacting Dirac equation is constructed. The
obtained equations lead to the Yang-Mills superfield with the appropriate
equations of motion for the component fields.Comment: 6 page
Recommended from our members
Structure functions of electroweak boson and leptons
The QCD structure of the electroweak bosons is reviewed and the lepton structure function is defined and calculated. The leading order splitting functions of electron into quarks are extracted, showing an important contribution from {gamma}-Z interference. Leading logarithmic QCD evolution equations are constructed and solved in the asymptotic region where log{sup 2} behavior of the Parton densities is observed. Possible applications with clear manifestation of ``resolved`` photon and weak bosons are discussed. 8 refs., 3 figs
Seeking for a fingerprint: analysis of point processes in actigraphy recording
Motor activity of humans displays complex temporal fluctuations which can be
characterized by scale-invariant statistics, thus documenting that structure
and fluctuations of such kinetics remain similar over a broad range of time
scales. Former studies on humans regularly deprived of sleep or suffering from
sleep disorders predicted change in the invariant scale parameters with respect
to those representative for healthy subjects. In this study we investigate the
signal patterns from actigraphy recordings by means of characteristic measures
of fractional point processes. We analyse spontaneous locomotor activity of
healthy individuals recorded during a week of regular sleep and a week of
chronic partial sleep deprivation. Behavioural symptoms of lack of sleep can be
evaluated by analysing statistics of duration times during active and resting
states, and alteration of behavioural organization can be assessed by analysis
of power laws detected in the event count distribution, distribution of waiting
times between consecutive movements and detrended fluctuation analysis of
recorded time series. We claim that among different measures characterizing
complexity of the actigraphy recordings and their variations implied by chronic
sleep distress, the exponents characterizing slopes of survival functions in
resting states are the most effective biomarkers distinguishing between healthy
and sleep-deprived groups.Comment: Communicated at UPON2015, 14-17 July 2015, Barcelona. 21 pages, 11
figures; updated: figures 4-7, text revised, expanded Sec. 1,3,
Fermi edge singularity in neutral electron-hole system
In neutral dense electron-hole (e-h) systems at low temperatures, theory
predicts Cooper-pair-like excitons at the Fermi energy and a BCS-like exciton
condensation. Optical excitation allows creating e-h systems with the densities
controlled by the excitation power. However, the intense optical excitations
required to achieve high densities cause substantial heating of the e-h system
that prevents the realization of dense and cold e-h systems in conventional
semiconductors. In this work, we study e-h systems created by optical
excitation in separated electron and hole layers. The layer separation
increases the e-h recombination time and, in turn, the density for a given
optical excitation by orders of magnitude and, as a result, enables the
realization of the dense and cold e-h system. We found a strong enhancement of
photoluminescence intensity at the Fermi energy of the neutral dense ultracold
e-h system that evidences the emergence of excitonic Fermi edge singularity due
to the Cooper-pair-like excitons at the Fermi energy
- …