2,177 research outputs found
An immersive system for browsing and visualizing surveillance video
HouseFly is an interactive data browsing and visualization system that synthesizes audio-visual recordings from multiple sensors, as well as the meta-data derived from those recordings, into a unified viewing experience. The system is being applied to study human behavior in both domestic and retail situations grounded in longitudinal video recordings. HouseFly uses an immersive video technique to display multiple streams of high resolution video using a realtime warping procedure that projects the video onto a 3D model of the recorded space. The system interface provides the user with simultaneous control over both playback rate and vantage point, enabling the user to navigate the data spatially and temporally. Beyond applications in video browsing, this system serves as an intuitive platform for visualizing patterns over time in a variety of multi-modal data, including person tracks and speech transcripts.United States. Office of Naval Research (Award no. N000140910187
Jet measurements at DO using a KT algorithm
DO has implemented and calibrated a KT jet algorithm for the first time in a
ppbar collider. We present two results based on 1992-1996 data which were
recently published: the subjet multiplicity in quark and gluon jets and the
central inclusive jet cross section. The measured ratio between subjet
multiplicities in gluon and quark jets is consistent with theoretical
predictions and previous experimental values. NLO pQCD predictions of the KT
inclusive jet cross section agree with the DO measurement, although marginally
in the low pT range. We also present a preliminary measurement of thrust cross
sections, which indicates the need to include higher than alpha_s^3 terms and
resumation in the theoretical calculations.Comment: 8 pages, 10 figures, presented at the High-Energy Physics
International Conference in Quantum Chromodynamics, Montpellier, France, July
2-9th 2002. To be published in Nuclear Physics
Review on alpha_s at LEP
To measure the strong coupling alpha_s from event shape observables two
ingredients are necessary. A perturbative prediction containing the dependence
of observables on alpha_s and a description of the hadronisation process to
match the perturbative prediction with the hadronic data.
As perturbative prediction O(alpha_s^2), NLLA and combined calculations are
available. Beside the well known Monte-Carlo based models also analytical
predictions, so called power corrections, exist to describe the hadronisation.
Advantages and disadvantages of the different resulting methods for determining
the strong coupling and its energy dependence will be discussed, the newest
DELPHI results will be presented, and an overview of the LEP results will be
included.Comment: To be published in the proceedings of Hadron99 held in Beijing,
24-28. Aug. 1999. 7 pages, 7 figures.
http://www.delphi.uni-wuppertal.de/qcd/Talks.html#Hadron9
Saturation Mutagenesis of the HIV-1 Envelope CD4 Binding Loop Reveals Residues Controlling Distinct Trimer Conformations
The conformation of HIV-1 envelope (Env) glycoprotein trimers is key in ensuring protection against waves of neutralizing antibodies generated during infection, while maintaining sufficient exposure of the CD4 binding site (CD4bs) for viral entry. The CD4 binding loop on Env is an early contact site for CD4 while penetration of a proximal cavity by CD4 triggers Env conformational changes for entry. The role of residues in the CD4 binding loop in regulating the conformation of the trimer and trimer association domain (TAD) was investigated using a novel saturation mutagenesis approach. Single mutations identified, resulted in distinct trimer conformations affecting CD4bs exposure, the glycan shield and the TAD across diverse HIV-1 clades. Importantly, mutations that improve access to the CD4bs without exposing the immunodominant V3 loop were identified. The different trimer conformations identified will affect the specificity and breadth of nabs elicited in vivo and are important to consider in design of Env immunogens for vaccines
Measurement of the forward Z boson production cross-section in pp collisions at TeV
A measurement of the production cross-section of Z bosons in pp collisions at TeV is presented using dimuon and dielectron final states in LHCb data. The cross-section is measured for leptons with pseudorapidities in the range , transverse momenta GeV and dilepton invariant mass in the range GeV. The integrated cross-section from averaging the two final states is \begin{equation*}\sigma_{\text{Z}}^{\ell\ell} = 194.3 \pm 0.9 \pm 3.3 \pm 7.6\text{ pb,}\end{equation*} where the first uncertainty is statistical, the second is due to systematic effects, and the third is due to the luminosity determination. In addition, differential cross-sections are measured as functions of the Z boson rapidity, transverse momentum and the angular variable
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
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
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