150,579 research outputs found
Do the gravitational corrections to the beta functions of the quartic and Yukawa couplings have an intrinsic physical meaning?
We study the beta functions of the quartic and Yukawa couplings of General
Relativity and Unimodular Gravity coupled to the and Yukawa
theories with masses. We show that the General Relativity corrections to those
beta functions as obtained from the 1PI functional by using the standard MS
multiplicative renormalization scheme of Dimensional Regularization are gauge
dependent and, further, that they can be removed by a non-multiplicative,
though local, field redefinition. An analogous analysis is carried out when
General Relativity is replaced with Unimodular Gravity. Thus we show that any
claim made about the change in the asymptotic behaviour of the quartic and
Yukawa couplings made by General Relativity and Unimodular Gravity lack
intrinsic physical meaning.Comment: 6 pages, 7 figure
Non-linear Symmetry-preserving Observer on Lie Groups
In this paper we give a geometrical framework for the design of observers on
finite-dimensional Lie groups for systems which possess some specific
symmetries. The design and the error (between true and estimated state)
equation are explicit and intrinsic. We consider also a particular case:
left-invariant systems on Lie groups with right equivariant output. The theory
yields a class of observers such that error equation is autonomous. The
observers converge locally around any trajectory, and the global behavior is
independent from the trajectory, which reminds of the linear stationary case.Comment: 12 pages. Submitted. Preliminary version publicated in french in the
CIFA proceedings and IFAC0
Possibility of observing MSSM charged Higgs in association with a W boson at LHC
Possibility of observing associated production of charged Higgs and W boson
in the framework of MSSM at LHC is studied. Both leptonic and hadronic decays
of W boson are studied while the charged Higgs boson is considered to decay to
a lepton and a neutrino. Therefore two search categories are defined
based on the leptonic and hadronic final states, i.e.
and where or and is a light jet from
decay. The discovery chance of the two categories is evaluated at an
integrated luminosity of 300 \invfb at LHC. It is shown that both leptonic and
hadronic final states have the chance of discovery at high \tanb. Finally
and contours are provided for both search categories.Comment: 20 pages, 19 figure
Implications of SUSY Model Building
We discuss the motivations and implications of models of low-energy
supersymmetry. We present the case for the minimal supersymmetric standard
model, which we define to include the minimal particle content and soft
supersymmetry-breaking interactions which are universal at the GUT or Planck
scale. This model is in agreement with all present experimental results, and
yet depends on only a few unknown parameters and therefore maintains
considerable predictive power. From the theoretical side, it arises naturally
in the context of supergravity models. We discuss radiative electroweak
symmetry breaking and the superpartner spectrum in this scenario, with some
added emphasis on regions of parameter space leading to unusual or interesting
experimental signals at future colliders. We then examine how these results may
be affected by various modifications and extensions of the minimal model,
including GUT effects, extended gauge, Higgs, and matter sectors, non-universal
supersymmetry breaking, non-conservation of R-parity, and dynamical
supersymmetry breaking at low energies.Comment: Contribution to the DPF long range study, working group on
'Electroweak Symmetry Breaking and Beyond the SM Physics'; LaTeX file without
figures, 60 pages. The complete PS file, including figures, can be obtained
by anonymous ftp from
ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-879.ps.
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When adolescents stop psychological therapy: rupture-repair in the therapeutic alliance and association with therapy ending
therapeutic alliance consistently predicts dropout from psychological therapy, and ruptures in the therapeutic alliance may also predict dropout, yet there is a dearth
of research with adolescents. This study investigated whether markers of rupturerepair in the therapeutic alliance were indicative of different types of treatment ending in adolescents who received psychological treatment for depression. Data were from the IMPACT study, a trial investigating the effectiveness of therapies for adolescent depression. Participants were randomly allocated to receive a psychological therapy: Brief Psychosocial Intervention, Cognitive-Behavioural Therapy or Short-Term Psychoanalytic Psychotherapy. The sample (N=35) comprised adolescents who had either completed their treatment (n=14) or dropped out (n=21) according to their therapist. Dropout cases were further classified as dissatisfied (n=14) or got-whatthey-
needed (n=7) based on post-therapy interviews with the adolescent and therapist. Selected audio-recordings of therapy sessions were rated using the Rupture Resolution Rating System and Working Alliance Inventory (observer-version). Therapeutic alliance and rupture-repair during therapy were similar for completers and got-what-they-needed dropouts, while dissatisfied dropouts had poorer
therapeutic alliance, more ruptures, ruptures were frequently unresolved, and therapists contributed to ruptures to a greater extent. Qualitative analysis of the sessions led to the construction of three categories of therapist contribution to
ruptures: therapist minimal response; persisting with a therapeutic activity; and focus on risk. Results suggest that ruptures, especially when unresolved, could be regarded
as warning signs of disengagement and dropout from psychological treatment. Future research should investigate how ruptures may be effectively identified and resolved in
treatment with adolescents
Symmetry-preserving Observers
This paper presents three non-linear observers on three examples of
engineering interest: a chemical reactor, a non-holonomic car, and an inertial
navigation system. For each example, the design is based on physical
symmetries. This motivates the theoretical development of invariant observers,
i.e, symmetry-preserving observers. We consider an observer to consist in a
copy of the system equation and a correction term, and we give a constructive
method (based on the Cartan moving-frame method) to find all the
symmetry-preserving correction terms. They rely on an invariant frame (a
classical notion) and on an invariant output-error, a less standard notion
precisely defined here. For each example, the convergence analysis relies also
on symmetries consideration with a key use of invariant state-errors. For the
non-holonomic car and the inertial navigation system, the invariant
state-errors are shown to obey an autonomous differential equation independent
of the system trajectory. This allows us to prove convergence, with almost
global stability for the non-holonomic car and with semi-global stability for
the inertial navigation system. Simulations including noise and bias show the
practical interest of such invariant asymptotic observers for the inertial
navigation system.Comment: To be published in IEEE Automatic Contro
On the evidence for brown-dwarf secondary stars in cataclysmic variables
We present the K-band spectrum of the cataclysmic variable LL And, obtained
using NIRSPEC on Keck-II. The spectrum shows no evidence for the absorption
features observed by Howell & Ciardi (2001), which these authors used to claim
a detection of a brown-dwarf secondary star in LL And. In light of our new
data, we review the evidence for brown-dwarf secondary stars in this and other
cataclysmic variables.Comment: 6 pages, to appear in Monthly Notices, accepte
Identifying capacitive and inductive loss in lumped element superconducting hybrid titanium nitride/aluminum resonators
We present a method to systematically locate and extract capacitive and
inductive losses in superconducting resonators at microwave frequencies by use
of mixed-material, lumped element devices. In these devices, ultra-low loss
titanium nitride was progressively replaced with aluminum in the
inter-digitated capacitor and meandered inductor elements. By measuring the
power dependent loss at 50 mK as the Al-TiN fraction in each element is
increased, we find that at low electric field, i.e. in the single photon limit,
the loss is two level system in nature and is correlated with the amount of Al
capacitance rather than the Al inductance. In the high electric field limit,
the remaining loss is linearly related to the product of the Al area times its
inductance and is likely due to quasiparticles generated by stray radiation. At
elevated temperature, additional loss is correlated with the amount of Al in
the inductance, with a power independent TiN-Al interface loss term that
exponentially decreases as the temperature is reduced. The TiN-Al interface
loss is vanishingly small at the 50 mK base temperature.Comment: 10 pages, 5 figure
Characterization and In-situ Monitoring of Sub-stoichiometric Adjustable Tc Titanium Nitride Growth
The structural and electrical properties of Ti-N films deposited by reactive
sputtering depend on their growth parameters, in particular the Ar:N2 gas
ratio. We show that the nitrogen percentage changes the crystallographic phase
of the film progressively from pure \alpha-Ti, through an \alpha-Ti phase with
interstitial nitrogen, to stoichiometric Ti2N, and through a substoichiometric
TiNX to stoichiometric TiN. These changes also affect the superconducting
transition temperature, Tc, allowing, the superconducting properties to be
tailored for specific applications. After decreasing from a Tc of 0.4 K for
pure Ti down to below 50 mK at the Ti2N point, the Tc then increases rapidly up
to nearly 5 K over a narrow range of nitrogen incorporation. This very sharp
increase of Tc makes it difficult to control the properties of the film from
wafer-to-wafer as well as across a given wafer to within acceptable margins for
device fabrication. Here we show that the nitrogen composition and hence the
superconductive properties are related to, and can be determined by,
spectroscopic ellipsometry. Therefore, this technique may be used for process
control and wafer screening prior to investing time in processing devices
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