2,132 research outputs found
Comparing Gluon to Quark Jets with DELPHI
This is a summary of the latest results of the DELPHI Collaboration on the
properties of identified quark and gluon jets. It covers the measurement of the
fragmentation functions of gluons and quarks and their scaling violation
behaviour as well as an analysis of the scale dependence of the multiplicities
in gluon and quark jets. Further, a precision measurement of CA/CF from the
multiplicities in symmetric three jet events is discussed.Comment: 7 pages, Latex. Perturbative QCD Session 5B Talk#5-15 DPF'9
Lane formation in a system of dipolar microswimmers
Using Brownian Dynamics (BD) simulations we investigate the non-equilibrium
structure formation of a two-dimensional (2D) binary system of dipolar colloids
propelling in opposite directions. Despite of a pronounced tendency for chain
formation, the system displays a transition towards a laned state reminiscent
of lane formation in systems with isotropic repulsive interactions. However,
the anisotropic dipolar interactions induce novel features: First, the lanes
have themselves a complex internal structure characterized by chains or
clusters. Second, laning occurs only in a window of interaction strengths. We
interprete our findings by a phase separation process and simple force balance
arguments
Novel structure formation of a phase separating colloidal fluid in a ratchet potential
Based on Dynamical Density Functional Theory (DDFT) we investigate a binary
mixture of interacting Brownian particles driven over a substrate via a
one-dimensional ratchet potential. The particles are modeled as soft spheres
where one component carries a classical Heisenberg spin. In the absence of a
substrate field, the system undergoes a first-order fluid-fluid demixing
transition driven by the spin-spin interaction. We demonstrate that the
interplay between the intrinsic spinodal decomposition and time-dependent
external forces leads to a novel dynamical instability where stripes against
the symmetry of the external potential form. This structural transition is
observed for a broad range of parameters related to the ratchet potential.
Moreover, we find intriguing effects for the particle transport.Comment: 6 pages, 4 figure
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