71 research outputs found
On an integral variant of incremental input/output-to-state stability and its use as a notion of nonlinear detectability
We propose a time-discounted integral variant of incremental
input/output-to-state stability (i-iIOSS) together with an equivalent Lyapunov
function characterization. Continuity of the i-iIOSS Lyapunov function is
ensured if the system satisfies a certain continuity assumption involving the
Osgood condition. We show that the proposed i-iIOSS notion is a necessary
condition for the existence of a robustly globally asymptotically stable
observer mapping in a time-discounted ``-to-'' sense. In
combination, our results provide a general framework for a Lyapunov-based
robust stability analysis of observers for continuous-time systems, which in
particular is crucial for the use of optimization-based state estimators (such
as moving horizon estimation).Comment: replaced with accepted versio
Robust Stability of Suboptimal Moving Horizon Estimation using an Observer-Based Candidate Solution
In this paper, we propose a suboptimal moving horizon estimator for nonlinear
systems. For the stability analysis we transfer the
"feasibility-implies-stability/robustness" paradigm from model predictive
control to the context of moving horizon estimation in the following sense:
Using a suitably defined, feasible candidate solution based on the trajectory
of an auxiliary observer, robust stability of the proposed suboptimal estimator
is inherited independently of the horizon length and even if no optimization is
performed.Comment: This work has been submitted to IFAC for possible publicatio
Queer Touch Between Holy Women: Julian of Norwich, Margery Kempe, Birgitta of Sweden, and the Visitation
Under embargo until: 2021-12-17This essay takes a new approach to the well-known meeting between two late-medieval English visionary women, Margery Kempe and the anchoress Julian of Norwich, as described in The Book of Margery Kempe. In this analysis their conversation subtly evokes a long history of women concentrating their subversive power through intimate, spiritual exchange, a history reaching back to the Biblical Visitation scene and expressed in its medieval artistic and literary instantiations. A queer reading illuminates the way that such female same-sex relationships challenge patriarchal systems by offering a privileged access to God outside clerical supervision. By examining Margery and Julian’s encounter, Luke’s Visitation passage, its depiction in a late-medieval Book of Hours, and comparing two different Middle English translations of a Visitation vision in Birgitta of Sweden’s Revelations, the full transgressive effect of queer touch between women—or even its unspoken possibility—emerges.acceptedVersio
Updated Determination of D⁰–D¯⁰Mixing and CP Violation Parameters with D⁰→K⁺π⁻ Decays
We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of D⁰→K⁺π⁻ to D⁰→K⁻π⁺ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of 5.0 fb⁻¹ recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters are determined to be x′²=(3.9±2.7)×10⁻⁵, y′=(5.28±0.52)×10⁻³, and R[subscript D]=(3.454±0.031)×10⁻³. Without this assumption, the measurement is performed separately for D⁰ and D[over ¯]⁰ mesons, yielding a direct CP-violating asymmetry A[subscript D]=(-0.1±9.1)×10⁻³, and magnitude of the ratio of mixing parameters 1.00<|q/p|<1.35 at the 68.3% confidence level. All results include statistical and systematic uncertainties and improve significantly upon previous single-measurement determinations. No evidence for CP violation in charm mixing is observed
Observation of D⁰ Meson Decays to Π⁺π⁻μ⁺μ⁻ and K⁺K⁻μ⁺μ⁻ Final States
The first observation of the D⁰→π⁺π⁻μ⁺μ⁻ and D⁰→K⁺K⁻μ⁺μ⁻ decays is reported using a sample of proton-proton collisions collected by LHCb at a center-of-mass energy of 8 TeV, and corresponding to 2 fb⁻¹ of integrated luminosity. The corresponding branching fractions are measured using as normalization the decay D⁰→K⁻π⁺[μ⁺μ⁻][subscript ρ⁰/ω], where the two muons are consistent with coming from the decay of a ρ⁰ or ω meson. The results are B(D⁰→π⁺π⁻μ⁺μ⁻)=(9.64±0.48±0.51±0.97)×10⁻⁷ and B(D⁰→K⁺K⁻μ⁺μ⁻)=(1.54±0.27±0.09±0.16)×10⁻⁷, where the uncertainties are statistical, systematic, and due to the limited knowledge of the normalization branching fraction. The dependence of the branching fraction on the dimuon mass is also investigated
Search for violation through an amplitude analysis of decays
International audienceA search for CP violation in the Cabibbo-suppressed D → KKππ decay mode is performed using an amplitude analysis. The measurement uses a sample of pp collisions recorded by the LHCb experiment during 2011 and 2012, corresponding to an integrated luminosity of 3.0 fb. The D mesons are reconstructed from semileptonic b-hadron decays into DμX final states. The selected sample contains more than 160 000 signal decays, allowing the most precise amplitude modelling of this D decay to date. The obtained amplitude model is used to perform the search for CP violation. The result is compatible with CP symmetry, with a sensitivity ranging from 1% to 15% depending on the amplitude considered
Updated determination of D 0 - D 0 mixing and C P violation parameters with D 0 → K + π -
We report measurements of charm-mixing parameters based on the decay-time-dependent ratio of D0→K+π- to D0→K-π+ rates. The analysis uses a data sample of proton-proton collisions corresponding to an integrated luminosity of 5.0 fb-1 recorded by the LHCb experiment from 2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters are determined to be x′2=(3.9±2.7)×10-5, y′=(5.28±0.52)×10-3, and RD=(3.454±0.031)×10-3. Without this assumption, the measurement is performed separately for D0 and D0 mesons, yielding a direct CP-violating asymmetry AD=(-0.1±9.1)×10-3, and magnitude of the ratio of mixing parameters 1.00<|q/p|<1.35 at the 68.3% confidence level. All results include statistical and systematic uncertainties and improve significantly upon previous single-measurement determinations. No evidence for CP violation in charm mixing is observed
Measurement of the Omega(0)(c) Baryon Lifetime
We report a measurement of the lifetime of the baryon using
proton-proton collision data at center-of-mass energies of 7 and 8~TeV,
corresponding to an integrated luminosity of 3.0 fb collected by the
LHCb experiment. The sample consists of about 1000
signal decays, where the
baryon is detected in the final state and
represents possible additional undetected particles in the decay. The
lifetime is measured to be
fs, where the uncertainties are statistical, systematic, and from the
uncertainty in the lifetime, respectively. This value is nearly four
times larger than, and inconsistent with, the current world-average value.Comment: 7 pages, 2 figures. All figures and tables, along with any
supplementary material and additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2018-028.htm
Updated determination of D-0-(D)over-bar(0) mixing and CP violation parameters with D-0 -> K+ pi(-) decays
We report measurements of charm-mixing parameters based on the
decay-time-dependent ratio of to rates. The
analysis uses a data sample of proton-proton collisions corresponding to an
integrated luminosity of fb recorded by the LHCb experiment from
2011 through 2016. Assuming charge-parity (CP) symmetry, the mixing parameters
are determined to be , , and . Without this
assumption, the measurement is performed separately for and
mesons, yielding a direct CP-violating asymmetry , and magnitude of the ratio of mixing parameters
at the confidence level. All results include
statistical and systematic uncertainties and improve significantly upon
previous single-measurement determinations. No evidence for CP violation in
charm mixing is observed.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2017-046.htm
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