2,666 research outputs found
Tests for circular symmetry of complex-valued random vectors
We propose tests for the null hypothesis that the law of a complex-valued
random vector is circularly symmetric. The test criteria are formulated as
-type criteria based on empirical characteristic functions, and they are
convenient from the computational point of view. Asymptotic as well as
Monte-Carlo results are presented. Applications on real data are also reported.
An R package called CircSymTest is available from the authors
Formalizing the transformations of a cognitive universe
International audienceIn an effort to continue the pioneering work of Harary in USA and Flament in France, we have undertaken to develop, on an experimental basis, a formalized theory of systems of beliefs and their modifications. This theory uses the psycho-social concepts of theories of cognitive consistency and of the tools of discrete mathematics, such as rewriting and intervals within graphs. The axioms and rewriting rules are elaborated from experimental data, and we demonstrate that the system we have built has the property of termination. This result is in accordance with experimental observations that show that every subject having an inconsistent system of beliefs (i.e., one containing contradictions) makes this system evolve towards consistency to reach a simple, consistent reference framework
LHC/ILC Interplay in SUSY Searches
Combined analyses at the Large Hadron Collider and at the International
Linear Collider are important to reveal precisely the new physics model as, for
instance, supersymmetry. Examples are presented where ILC results as input for
LHC analyses could be crucial for the identification of signals as well as of
the underlying model. The synergy of both colliders leads also to rather
accurate SUSY parameter determination and powerful mass constraints even if the
scalar particles have masses in the multi-TeV range.Comment: 5 pages, contribution to the proceedings of EPS0
Model-Independent Bounds on a Light Higgs
We present up-to-date constraints on a generic Higgs parameter space. An
accurate assessment of these exclusions must take into account statistical, and
potentially signal, fluctuations in the data currently taken at the LHC. For
this, we have constructed a straightforward statistical method for making full
use of the data that is publicly available. We show that, using the expected
and observed exclusions which are quoted for each search channel, we can fully
reconstruct likelihood profiles under very reasonable and simple assumptions.
Even working with this somewhat limited information, we show that our method is
sufficiently accurate to warrant its study and advocate its use over more naive
prescriptions. Using this method, we can begin to narrow in on the remaining
viable parameter space for a Higgs-like scalar state, and to ascertain the
nature of any hints of new physics---Higgs or otherwise---appearing in the
data.Comment: 32 pages, 10 figures; v3: correction made to basis of four-derivative
operators in the effective Lagrangian, references adde
Measuring the Higgs Sector
If we find a light Higgs boson at the LHC, there should be many observable
channels which we can exploit to measure the relevant parameters in the Higgs
sector. We use the SFitter framework to map these measurements on the parameter
space of a general weak-scale effective theory with a light Higgs state of mass
120 GeV. Our analysis benefits from the parameter determination tools and the
error treatment used in new--physics searches, to study individual parameters
and their error bars as well as parameter correlations.Comment: 45 pages, Journal version with comments from refere
Dark matter searches at LHC
Besides Standard Model measurements and other Beyond Standard Model studies,
the ATLAS and CMS experiments at the LHC will search for Supersymmetry, one of
the most attractive explanation for dark matter. The SUSY discovery potential
with early data is presented here together with some first results obtained
with 2010 collision data at 7 TeV. Emphasis is placed on measurements and
parameter determination that can be performed to disentangle the possible SUSY
models and SUSY look-alike and the interpretation of a possible positive
supersymmetric signal as an explanation of dark matter.Comment: 15 pages, 14 figures, Invited plenary talk given at DISCRETE 2010:
Symposium On Prospects In The Physics Of Discrete Symmetries, 6-11 Dec 2010,
Rome, Ital
Determining R-parity violating parameters from neutrino and LHC data
In supersymmetric models neutrino data can be explained by R-parity violating
operators which violate lepton number by one unit. The so called bilinear model
can account for the observed neutrino data and predicts at the same time
several decay properties of the lightest supersymmetric particle. In this paper
we discuss the expected precision to determine these parameters by combining
neutrino and LHC data and discuss the most important observables. We show that
one can expect a rather accurate determination of the underlying R-parity
parameters assuming mSUGRA relations between the R-parity conserving ones and
discuss briefly also the general MSSM as well as the expected accuracies in
case of a prospective e+ e- linear collider. An important observation is that
several parameters can only be determined up to relative signs or more
generally relative phases.Comment: 13 pages, 13 figure
Full order alpha electroweak corrections to double Higgs-strahlung at the linear collider
We present the full order alpha electroweak radiative corrections to the
double Higgs-strahlung process e+e- --> ZHH. The computation is performed with
the help of GRACE-loop. After subtraction of the initial state QED radiative
corrections, we find that the genuine weak corrections in the -scheme
are small for Higgs masses and energies where this cross section is largest and
is most likely to be studied. These corrections decrease with increasing
energies attaining about at TeV. The full order alpha
correction on the other hand is quite large at threshold but small at energies
around the peak. We also study changes in the shape of the invariant mass of
the Higgs pair which has been shown to be a good discriminating variable for
the measurement of the triple Higgs vertex in this reaction.Comment: 18 pages, 5 figures and 3 table
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