33 research outputs found
Elementary linear algebra for advanced spectral problems
We discuss the general method of Grushin problems, closely related to Shur
complements, Feshbach projections and effective Hamiltonians, and describe
various appearances in spectral theory, pdes, mathematical physics and
numerical problems.Comment: 2 figure
Measurement of heavy-flavor production in Pb-Pb collisions at the LHC with ALICE
A Large Ion Collider Experiment (ALICE) at the Large Hadron Collider (LHC)
has been built in order to study the Quark-Gluon Plasma (QGP) created in
high-energy nuclear collisions. As heavy-flavor quarks are produced at the
early stage of the collision, they serve as sensitive probes for the QGP. The
ALICE detector with its capabilities such as particle identification, secondary
vertexing and tracking in a high multiplicity environment can address, among
other measurements, the heavy-flavor sector in heavy-ion collisions. We present
latest results on the measurement of the nuclear modification factor of open
heavy-flavors as well as on the measurement of open heavy-flavor azimuthal
anisotropy v2 in Pb-Pb collisions at sqrt(s) = 2.76 TeV. Open charmed hadrons
are reconstructed in the hadronic decay channels D0->Kpi, D+->Kpipi, and
D*+->D0pi applying a secondary decay-vertex topology. Complementary
measurements are performed by detecting electrons (muons) from semi-leptonic
decays of open heavy-flavor hadrons in the central (forward) rapidity region.Comment: 10 pages, 6 figures. Talk given by Robert Grajcarek at the 11th
International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio,
Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in
Journal of Physics: Conference Series (JPCS
Strangeness enhancement from strong color fields at RHIC
In ultra-relativistic heavy ion collisions, early stage multiple scatterings
may lead to an increase of the color electric field strength. Consequently,
particle production - especially heavy quark (and di-quark) production - is
greatly enhanced according to the Schwinger mechanism. We test this idea via
the Ultra-relativistic Quantum Molecular Dynamics model (UrQMD) for Au+Au
collisions at the full RHIC energy ( AGeV). Relative to p+p
collisions, a factor of 60, 20 and 7 enhancement respectively, for
(), (), and , () is predicted for a model
with increased color electric field strength
Scaling violations: Connections between elastic and inelastic hadron scattering in a geometrical approach
Starting from a short range expansion of the inelastic overlap function,
capable of describing quite well the elastic pp and scattering data,
we obtain extensions to the inelastic channel, through unitarity and an impact
parameter approach. Based on geometrical arguments we infer some
characteristics of the elementary hadronic process and this allows an excellent
description of the inclusive multiplicity distributions in and
collisions. With this approach we quantitatively correlate the violations of
both geometrical and KNO scaling in an analytical way. The physical picture
from both channels is that the geometrical evolution of the hadronic
constituents is principally reponsible for the energy dependence of the
physical quantities rather than the dynamical (elementary) interaction itself.Comment: 16 pages, aps-revtex, 11 figure