3,362 research outputs found
Reconstructing Supersymmetry at ILC/LHC
Coherent analyses of experimental results from LHC and ILC will allow us to
draw a comprehensive and precise picture of the supersymmetric particle sector.
Based on this platform the fundamental supersymmetric theory can be
reconstructed at the high scale which is potentially close to the Planck scale.
This procedure will be reviewed for three characteristic examples: minimal
supergravity as the paradigm; a left-right symmetric extension incorporating
intermediate mass scales; and a specific realization of string effective
theories.Comment: published in Proceedings of the Ustron Conference 2005; technical
LaTeX problem correcte
An algebra of deformation quantization for star-exponentials on complex symplectic manifolds
The cotangent bundle to a complex manifold is classically endowed
with the sheaf of \cor-algebras \W[T^*X] of deformation quantization, where
\cor\eqdot \W[\rmptt] is a subfield of \C[[\hbar,\opb{\hbar}]. Here, we
construct a new sheaf of \cor-algebras \TW[T^*X] which contains \W[T^*X]
as a subalgebra and an extra central parameter . We give the symbol calculus
for this algebra and prove that quantized symplectic transformations operate on
it. If is any section of order zero of \W[T^*X], we show that
\exp(t\opb{\hbar} P) is well defined in \TW[T^*X].Comment: Latex file, 24 page
Constraining SUSY Dark Matter with the ATLAS Detector at the LHC
In the event that R-Parity conserving supersymmetry (SUSY) is discovered at
the LHC, a key issue which will need to be addressed will be the consistency of
that signal with astrophysical and non-accelerator constraints on SUSY Dark
Matter. This issue is studied for the SPS1a mSUGRA benchmark model by using
measurements of end-points and thresholds in the invariant mass spectra of
various combinations of leptons and jets in ATLAS to constrain the model
parameters. These constraints are then used to assess the statistical accuracy
with which quantities such as the Dark Matter relic density and direct
detection cross-section can be measured. Systematic effects arising from the
use of different mSUGRA RGE codes are also estimated. Results indicate that for
SPS1a a statistical(systematic) precision on the relic abundance ~ 2.8% (3 %)
can be obtained given 300 fb-1 of data.Comment: 11 pages, 10 encapsulated postscript figures. Minor modification to
ref
Dark Matter and LHC: What is the Connection?
We review what can (and cannot) be learned if dark matter is detected in one
or more experiments, emphasizing the importance of combining LHC data with
direct, astrophysical and cosmological probes of dark matter. We briefly review
the conventional picture of a thermally produced WIMP relic density and its
connection with theories of electroweak symmetry breaking. We then discuss both
experimental and theoretical reasons why one might generically expect this
picture to fail. If this is the case, we argue that a combined effort bringing
together all types of data -- combined with explicitly constructed theoretical
models -- will be the only way to achieve a complete understanding of the dark
matter in our universe and become confident that any candidate actually
provides the relic density.Comment: 25 pages, 2 figures, Invited review for Modern Physics Letters
Invariant mass distributions in cascade decays
We derive analytical expressions for the shape of the invariant mass
distributions of massless Standard Model endproducts in cascade decays
involving massive New Physics (NP) particles, D -> Cc -> Bbc -> Aabc, where the
final NP particle A in the cascade is unobserved and where two of the particles
a, b, c may be indistinguishable. Knowledge of these expressions can improve
the determination of NP parameters at the LHC. The shape formulas are
composite, but contain nothing more complicated than logarithms of simple
expressions. We study the effects of cuts, final state radiation and detector
effects on the distributions through Monte Carlo simulations, using a
supersymmetric model as an example. We also consider how one can deal with the
width of NP particles and with combinatorics from the misidentification of
final state particles. The possible mismeasurements of NP masses through `feet'
in the distributions are discussed. Finally, we demonstrate how the effects of
different spin configurations can be included in the distributions.Comment: 39 pages, 14 figures (colour), JHEP clas
ARTHROSCOPIC TREATMENT OF FEMOROACETABULAR IMPINGEMENT
ABSTRACTObjective: The purpose of this study is to evaluate the short-term follow-up results of arthroscopic treatment of femoroacetabular impingement. Our hypothesis is that arthroscopic treatment results are favorable. Methods: Between August 2003 and August 2007, 28 hips had femoroacetabular impingement treated by hip arthroscopy. The mean age was 34 years, with mean follow-up period of 27 months. Clinical results were graded with the modified Harris hip score, which was measured pre- and postoperatively. Patients had also their internal rotation analyzed. These parameters were calculated by using Wilcoxon's t test for analysis of nonparametric paired samples performed. Results: The mean preoperative Harris Hip Score was 54.2, improving to 94.8 postoperatively (p<0,001). The mean increase was 37.5 points. We had 4 good results (15%) and 24 excellent results (85%). Preoperatively, the patients had a mean internal rotation of 17°, and, postoperatively, 36°. The average internal rotation increase was 19° (p<0,001). Conclusions: The arthroscopic treatment of femoroacetabular impingement presents satisfactory results
Unique Identification of Lee-Wick Gauge Bosons at Linear Colliders
Grinstein, O'Connell and Wise have recently presented an extension of the
Standard Model (SM), based on the ideas of Lee and Wick (LW), which
demonstrates an interesting way to remove the quadratically divergent
contributions to the Higgs mass induced by radiative corrections. This model
predicts the existence of negative-norm copies of the usual SM fields at the
TeV scale with ghost-like propagators and negative decay widths, but with
otherwise SM-like couplings. In earlier work, it was demonstrated that the LW
states in the gauge boson sector of these models, though easy to observe,
cannot be uniquely identified as such at the LHC. In this paper, we address the
issue of whether or not this problem can be resolved at an collider
with a suitable center of mass energy range. We find that measurements of the
cross section and the left-right polarization asymmetry associated with Bhabha
scattering can lead to a unique identification of the neutral electroweak gauge
bosons of the Lee-Wick type.Comment: 16 pages, 6 figures; discussion and references adde
Preclinical animal acute toxicity studies of new developed MRI contrast agent based on gadolinium
Acute toxicity test of new developed MRI contrast agent based on disodium salt of gadopentetic acid complex were carried out on Mus musculus and Sprague Dawley rats according to guidelines of preclinical studies [1]. Groups of six animals each were selected for experiment. Death and clinical symptoms of animals were recorded during 14 days. As a result the maximum tolerated dose (MTD) for female mice is 2.8 mМ/kg of body weight, male mice - 1.4 mМ/kg, female rats - 2.8 mМ/kg, male rats - 5.6 mМ/kg of body weight. No Observed Adverse Effect Dose (NOAEL) for female mice is 1.4 mМ/kg, male mice - 0.7 mМ/kg, male and female rats - 0.7 mМ/kg. According to experimental data new developed MRI contrast agent based on Gd-DTPA complex is low-toxic
A scalable data taking system at a test beam for LHC
We propose the installation of a data taking system at a test beam for the simultaneous test of LHC detectors, trigger and readout electronics, together with the development of the supporting architecture in a multiprocessor environment. A strong emphasis is put on a highly modular design, such that new hardware and software developments can be conveniently introduced for training and evaluation. One of the main thrusts of the project will be the modelling and system integration of different readout architectures, which are meant to provide a valuable training ground for new techniques. To address these aspects in a realistic manner, we propose to collaborate with two detector R+D projects
Measurement of the Gluino Mass via Cascade Decays for SPS 1a
If R-parity conserving supersymmetry is realised with masses below the TeV
scale, sparticles will be produced and decay in cascades at the LHC. In the
case of a neutral LSP, which will not be detected, decay chains cannot be fully
reconstructed, complicating the mass determination of the new particles. In
this paper we extend the method of obtaining masses from kinematical endpoints
to include a gluino at the head of a five-sparticle decay chain. This
represents a non-trivial extension of the corresponding method for the squark
decay chain. We calculate the endpoints of the new distributions and assess
their applicability by examining the theoretical distributions for a variety of
mass scenarios. The precision with which the gluino mass can be determined by
this method is investigated for the mSUGRA point SPS 1a. Finally we estimate
the improvement obtained from adding a Linear Collider measurement of the LSP
mass.Comment: 40 pages; extended discussion of error
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