16,642 research outputs found
A New Hypothesis on the Origin of the Three Generations
We suggest that the Standard Model may undergo a supercritical transition
near the Landau scale, where the U(1) gauge boson couples to the left and right
handed states of any given fermion with different charges. This scenario
naturally gives rise to three generations of fermion, corresponding to the
three critical scales for the right-right, right-left and left-left fermion
interactions going supercritical, as well as CP violation in the quark sector.Comment: 12 pages, LaTeX, To appear in Mod.Phys.Lett.A (1996
Gluon polarization in the proton
We combine heavy-quark renormalization group arguments with our understanding
of the nucleon's wavefunction to deduce a bound on the gluon polarization Delta
g in the proton. The bound is consistent with the values extracted from spin
experiments at COMPASS and RHIC.Comment: 4 page
Azimuthal correlations of pions in relativistic heavy ion collisions at 1 GeV/nucl.
Triple differential cross sections of pions in heavy ion collisions at 1
GeV/nucl. are studied with the IQMD model. After discussing general properties
of resonance and pion production we focus on azimuthal correlations:
At projectile- and target-rapidities we observe an anticorrelation in the
in-plane transverse momentum between pions and protons. At c.m.-rapidity,
however, we find that high pions are being preferentially emitted
perpendicular to the event-plane. We investigate the causes of those
correlations and their sensitivity on the density and momentum dependence of
the real and imaginary part of the nucleon and pion optical potential.Comment: 40 pages, 18 eps-figures, uses psfig.sty; complete postscript file
available at ftp://th.physik.uni-frankfurt.de/pub/bass/GSI-preprint_95-7.ps.
Circadian Disruption and Metabolic Disease: Findings from Animal Models
Social opportunities and work demands have caused humans to become increasingly active during the late evening hours, leading to a shift from the predominantly diurnal lifestyle of our ancestors to a more nocturnal one. This voluntarily decision to stay awake long into the evening hours leads to circadian disruption at the system, tissue, and cellular levels. These derangements are in turn associated with clinical impairments in metabolic processes and physiology. The use of animal models for circadian disruption provides an important opportunity to determine mechanisms by which disorganization in the circadian system can lead to metabolic dysfunction in response to genetic, environmental, and behavioral perturbations. Here we review recent key animal studies involving circadian disruption and discuss the possible translational implications of these studies for human health and particularly for the development of metabolic disease
The Disappearance of Flow
We investigate the disappearance of collective flow in the reaction plane in
heavy-ion collisions within a microscopic model (QMD). A systematic study of
the impact parameter dependence is performed for the system Ca+Ca. The balance
energy strongly increases with impact parameter. Momentum dependent
interactions reduce the balance energies for intermediate impact parameters
fm. Dynamical negative flow is not visible in the laboratory
frame but does exist in the contact frame for the heavy system Au+Au. For
semi-peripheral collisions of Ca+Ca with fm a new two-component
flow is discussed. Azimuthal distributions exhibit strong collectiv flow
signals, even at the balance energy.Comment: 19 pages, 7 eps-figures, uses psfig.sty; complete postscript file
available at
ftp://th.physik.uni-frankfurt.de/pub/bass/GSI-preprint_95-11.ps.
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