8,894 research outputs found
Charge-dependent anisotropic flow studies and the search for the Chiral Magnetic Wave in ALICE
Theoretical calculations have shown the possibility of P-violating bubbles in
the QCD vacuum, which in combination with the strong magnetic field created in
off-central heavy-ion collisions lead to novel effects such as the Chiral
Magnetic Effect (CME) and the Chiral Separation Effect (CSE). A coupling
between the CME and the CSE produces a wave-like excitation called the Chiral
Magnetic Wave (CMW). The CMW produces a quadrupole moment that always has the
same sign and is therefore present in an average over events. In this talk we
present a series of charge-dependent anisotropic flow measurements in Pb--Pb
collisions at = 2.76 TeV in ALICE, using two- and
three-particle correlators with unidentified hadrons. The relation of these
measurements to the search for the CMW is discussed.Comment: 4 pages, 4 figures, Proceedings of XXIV International Conference on
Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2014), May 19-24,
2014, Darmstad
Teflon-packed flexible joint
Teflon-packed flexible joint separates the movement of the shaker from the liquid nitrogen hose during the ground testing of cryogenic zero-g equipment. The joint allows the hose to lie on the floor in a stationary position as the shaker moves back and forth, thus, the hose is not subject to violent motion
Does Active Management Benefit Endowment Returns?
We conduct a longitudinal analysis of the NACUBO Commonfund Study of Endowments (NCSE) results from 2006-2013 to evaluate if active management is related to higher endowment returns in U.S. equities over time. We also analyze the data to evaluate the endowment characteristics that are related to higher levels of performance over time.We find that active management for endowments is significantly positively related to higher returns net of fees from U.S. equity allocations over the evaluation period. In addition, endowments with CIOs or OCIOs are better able to earn incremental positive returns from active management than those without. Larger endowments are better able to earn incremental positive returns from active management than the smallest endowments but the effect appears to diminish as endowments increase in size
Ozone Contamination in Aircraft Cabins. Appendix B: Overview papers. Flight 8 planning to avoid high ozone
The problem of preventing cabin ozone from exceeding a given standard was investigated. Statistical analysis of vertical distribution of ozone is summarized. The cost, logistics, maintenance, ability to forecast ozone, and avoiding high ozone concentrations are presented. Filtering approaches and the requirements to remove ozone toxicity are discussed
New insight into short wavelength solar wind fluctuations from Vlasov theory
The nature of solar wind (SW) turbulence below the proton gyroscale is a
topic that is being investigated extensively nowadays. Although recent
observations gave evidence of the dominance of Kinetic Alfv\'en Waves (KAW) at
sub-ion scales with , other studies suggest that the KAW
mode cannot carry the turbulence cascade down to electron scales and that the
whistler mode (i.e., ) is more relevant. Here, we propose
to study key properties of the short wavelength plasma modes under realistic SW
conditions, typically and for high oblique
angles of propagation as observed from
the Cluster data. The linear properties of the plasma modes under these
conditions are poorly known, which contrasts with the well-documented cold
plasma limit and/or moderate oblique angles of propagation (). Based on linear solutions of the Vlasov kinetic theory, we discuss
the relevance of each plasma mode (fast, Bernstein, KAW, whistler) in carrying
the energy cascade down to electron scales. We show, in particular, that the
shear Alfv\'en mode extends at scales following either a
whistler mode () or a KAW mode (with )
depending on the anisotropy . This contrasts with the
well-accepted idea that the whistler branch develops as a continuation at high
frequencies of the fast magnetosonic mode. We show, furthermore, that the
whistler branch is more damped than the KAW one, which makes the latter a more
relevant candidate to carry the energy cascade down to electron scales. We
discuss how these new findings may facilitate resolution of the controversy
concerning the nature of the small scale turbulence, and we discuss the
implications for present and future spacecraft wave measurements in the SW.Comment: 11 pages, 12 figures, submitted to Astrophysical Journa
Radiation processes around accreting black holes
Accreting sources such as AGN, X-ray binaries or gamma-ray bursts are known
to be strong, high energy emitters. The hard emission is though to originate
from plasmas of thermal and/or non-thermal high energy particles. Not only does
this emission allow to probe the unique properties of the matter in an extreme
environment, but it also has a crucial backreaction on the energetics and the
dynamics of the emitting medium itself. Understanding interactions between
radiation and matter has become a key issue in the modelling of high energy
sources. Although most cross sections are well known, they are quite complex
and the way all processes couple non-linearly is still an open issue.
We present a new code that solves the local, kinetic evolution equations for
distributions of electrons, positrons and photons, interacting by radiation
processes such as self-absorbed synchrotron and brems-strahlung radiation,
Compton scattering, pair production/annihilation, and by Coulomb collisions.
The code is very general and aimed to modelled various high energy sources. As
an application, we study the spectral states of X-ray binaries, including
thermalization by Coulomb collisions and synchrotron self-absorption. It is
found that the low-hard and high-soft states can be modelled with different
illumination but the same non-thermal acceleration mechanism.Comment: 4 pages, 2 figures, proceedings of the SF2A conference 200
Energy Loss and Flavor Dynamics from Single Particle Measurements in PHENIX
The transverse momentum spectra, yields, and ratios of charged pions,
protons, and antiprotons have been studied up to 5 GeV/c in in 5
different centrality classes in Au+Au collisions at = 200 GeV.
These results are compared and contrasted with the observables calculated in
recombination models of hadronization. They are also used to examine the color
charge dependence of parton energy loss in the medium.Comment: 4 pages, 6 figures, to appear in the Proceedings of Quark Matter 200
The x-ray corona and jet of cygnus x-1
Evidence is presented indicating that in the hard state of Cygnus X-1, the
coronal mag- netic field might be below equipartition with radiation
(suggesting that the corona is not powered by magnetic field dissipation) and
that the ion temperature in the corona is significantly lower than what
predicted by ADAF like models. It is also shown that the current estimates of
the jet power set interesting contraints on the jet velocity (which is at least
mildly relativistic), the accretion efficiency (which is large in both spectral
states), and the nature of the X-ray emitting region (which is unlikely to be
the jet).Comment: 8 pages, 1 figure. Accepted for publication in Journal of Modern
Physics D, Proceedings of HEPRO II conference, Buenos Aires, Argentina,
October 26-30, 200
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