63,378 research outputs found
A psychoanalytic concept illustrated: Will, must, may, can â revisiting the survival function of primitive omnipotence
The author explores the linear thread connecting the theory of Freud and Klein, in terms of the central significance of the duality of the life and death instinct and the capacity of the ego to tolerate contact with internal and external reality. Theoretical questions raised by later authors, informed by clinical work with children who have suffered deprivation and trauma in infancy, are then considered. Theoretical ideas are illustrated with reference to observational material of a little boy who suffered deprivation and trauma in infancy. He was first observed in the middle of his first year of life while he was living in foster care, and then later at the age of two years and three months, when he had been living with his adoptive parents for more than a year
Inclination-dependent spectral and timing properties in transient black hole X-ray binaries
We use a simple one-dimensional parameterisation of timing properties to show
that hard and hard-intermediate state transient black hole X-ray binaries with
the same power-spectral shape have systematically harder X-ray power-law
emission in higher-inclination systems. We also show that the power-spectral
shape and amplitude of the broadband noise (with low-frequency quasi-periodic
oscillations, QPOs, removed) is independent of inclination, confirming that it
is well-correlated with the intrinsic structure of the emitting regions and
that the "type C" QPO, which is inclination-dependent, has a different origin
to the noise, probably geometric. Our findings suggest that the power-law
emission originates in a corona which is flattened in the plane of the disc,
and not in a jet-like structure which would lead to softer spectra at higher
inclinations. However, there is tentative evidence that the
inclination-dependence of spectral shape breaks down deeper into the hard
state. This suggests either a change in the coronal geometry and possible
evidence for contribution from jet emission, or alternatively an even more
optically thin flow in these states.Comment: 6 Pages, 4 Figures, accepted as a Letter by MNRA
Power-Colours: Simple X-ray Binary Variability Comparison
We demonstrate a new method of variability classification using observations
of black hole X-ray binaries. Using `power colours' -- ratios of integrated
power in different Fourier frequency bands -- we can clearly differentiate
different canonical black hole states as the objects evolve during outburst. We
analyse (~ 2400) Rossi X-ray Timing Explorer observations of 12 transient low
mass black hole X-ray binaries and find that the path taken around the power
colour-colour diagram as the sources evolve is highly consistent from object to
object. We discuss how the consistency observed in the power colour-colour
diagram between different objects allows for easy state classification based on
only a few observations, and show how the power-spectral shapes can be simply
classified using a single parameter, the power-spectral `hue'. To illustrate
the benefits of our simple model-independent approach, we show that the
persistent high mass X-ray binary Cyg X-1 shows very similar power-spectral
evolution to the transient black hole sources, with the main difference being
caused by a combination of a lack of quasi-periodic oscillations and an excess
of low-frequency power-law noise in the Cyg X-1 power spectra during the
transitional state. We also compare the transient objects to the neutron star
atoll source Aquila X-1, demonstrating that it traces a different path in the
power colour-colour plot. Thus, power-colours could be an effective method to
classify newly discovered X-ray binaries.Comment: 13 pages, 9 figures, accepted by MNRA
Possible solution of the Coriolis attenuation problem
The most consistently useful simple model for the study of odd deformed
nuclei, the particle-rotor model (strong coupling limit of the core-particle
coupling model) has nevertheless been beset by a long-standing problem: It is
necessary in many cases to introduce an ad hoc parameter that reduces the size
of the Coriolis interaction coupling the collective and single-particle
motions. Of the numerous suggestions put forward for the origin of this
supplementary interaction, none of those actually tested by calculations has
been accepted as the solution of the problem. In this paper we seek a solution
of the difficulty within the framework of a general formalism that starts from
the spherical shell model and is capable of treating an arbitrary linear
combination of multipole and pairing forces. With the restriction of the
interaction to the familiar sum of a quadrupole multipole force and a monopole
pairing force, we have previously studied a semi-microscopic version of the
formalism whose framework is nevertheless more comprehensive than any
previously applied to the problem. We obtained solutions for low-lying bands of
several strongly deformed odd rare earth nuclei and found good agreement with
experiment, except for an exaggerated staggering of levels for K=1/2 bands,
which can be understood as a manifestation of the Coriolis attenuation problem.
We argue that within the formalism utilized, the only way to improve the
physics is to add interactions to the model Hamiltonian. We verify that by
adding a magnetic dipole interaction of essentially fixed strength, we can fit
the K=1/2 bands without destroying the agreement with other bands. In addition
we show that our solution also fits 163Er, a classic test case of Coriolis
attenuation that we had not previously studied.Comment: revtex, including 7 figures(postscript), submitted to Phys.Rev.
Threshold expansion of massive coloured particle cross sections
Pair production of massive coloured particles in hadron collisions is
accompanied by potentially large radiative corrections related to the
suppression of soft gluon emission and enhanced Coulomb exchange near the
production threshold. We recently developed a framework to sum both series of
corrections for the partonic cross section using soft-collinear and
non-relativistic effective theory. If it can be argued that the resummed cross
section approximates the complete result over a significant kinematic range, an
improvement of the hadronic cross section results, even when the production is
not kinematically constrained to the threshold. This is discussed here for the
case of top quark production.Comment: 5 pages, to appear in: Proceedings of the 10th DESY Workshop on
Elementary Particle Theory: Loops and Legs in Quantum Field Theory 2010,
W\"orlitz, Germany, 25-30 Apr 201
Derivation and assessment of strong coupling core-particle model from the Kerman-Klein-D\"onau-Frauendorf theory
We review briefly the fundamental equations of a semi-microscopic
core-particle coupling method that makes no reference to an intrinsic system of
coordinates. We then demonstrate how an intrinsic system can be introduced in
the strong coupling limit so as to yield a completely equivalent formulation.
It is emphasized that the conventional core-particle coupling calculation
introduces a further approximation that avoids what has hitherto been the most
time-consuming feature of the full theory, and that this approximation can be
introduced either in the intrinsic system, the usual case, or in the laboratory
system, our preference. A new algorithm is described for the full theory that
largely removes the difference in complexity between the two types of
calculation. Comparison of the full and approximate theories for some
representative cases provides a basis for the assessment of the accuracy of the
traditional approach. We find that for well-deformed nuclei, e.g. 157Gd and
157Tb, the core-coupling method and the full theory give similar results.Comment: revtex, 3 figures(postscript), submitted to Phys.Rev.
Jet reconstruction and jet background classification with the ALICE experiment in PbPb collisions at the LHC
For a quantitative interpretation of reconstructed jet properties in
heavy-ion collisions it is paramount to characterize the contribution from the
underlying event and the influence of background fluctuations on the jet
signal. In addition to the pure number fluctuations, region-to-region
correlated background within one event can enhance or deplete locally the level
of background and modify the jet energy. We show a first detailed assessment of
background effects using different probes embedded into heavy-ion data and
quantify their influence on the reconstructed jet spectrum.Comment: 4 pages, 2 figures, Proceedings for the XXII International Conference
on Ultra-Relativistic Nucleus-Nucleus Collisions, Quark Matter 2011, Annec
How robust is a thermal photon interpretation of the ALICE low-p_T data?
We present a rigorous theoretical analysis of the ALICE measurement of
low-p_T direct-photon production in central lead-lead collisions at the LHC
with a centre-of-mass energy of \sqrt{s_{NN}}=2.76 TeV. Using NLO QCD, we
compute the relative contributions to prompt-photon production from different
initial and final states and the theoretical uncertainties coming from
independent variations of the renormalisation and factorisation scales, the
nuclear parton densities and the fragmentation functions. Based on different
fits to the unsubtracted and prompt-photon subtracted ALICE data, we
consistently find T = 304 \pm 58 MeV and 309 \pm 64 MeV for the effective
temperature of the quark-gluon plasma (or hot medium) at p_T \in [0.8;2.2] GeV
and p_T \in [1.5;3.5] GeV as well as a power-law (p_T^{-4}) behavior for p_T >
4 GeV as predicted by QCD hard scattering.Comment: 18 pages, 7 figures, 1 tabl
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