9 research outputs found
Contribution française à l'upgrade de LHCb
La contribution française à l'upgrade de LHCb est d etaillée dans ce document et s'inscrit dans le prolongement du Framework TDR soumis au LHCC le 25 mai 2012. La France a contribué à la conception et à la réalisation de la mécanique et de l'électronique de lecture des calorimètres. Elle est l'acteur principal du système de déclenchement de premier niveau et l'initiatrice du projet DIRAC, progiciel de traitement et d'analyse de données dans un environnement distribué. Les physiciens et ingénieurs français ont de nombreuses responsabilités de premier plan et sont très fortement impliqués dans l'analyse des données. Les groupes français souhaitent poursuivre leur forte participation a l'expérience en contribuant a son upgrade, notamment l'électronique de lecture des calorimètres et du trajectographe en fibres scintillantes ainsi qu'au data processing
Contribution française à l'upgrade de LHCb
La contribution française à l'upgrade de LHCb est d etaillée dans ce document et s'inscrit dans le prolongement du Framework TDR soumis au LHCC le 25 mai 2012. La France a contribué à la conception et à la réalisation de la mécanique et de l'électronique de lecture des calorimètres. Elle est l'acteur principal du système de déclenchement de premier niveau et l'initiatrice du projet DIRAC, progiciel de traitement et d'analyse de données dans un environnement distribué. Les physiciens et ingénieurs français ont de nombreuses responsabilités de premier plan et sont très fortement impliqués dans l'analyse des données. Les groupes français souhaitent poursuivre leur forte participation a l'expérience en contribuant a son upgrade, notamment l'électronique de lecture des calorimètres et du trajectographe en fibres scintillantes ainsi qu'au data processing
Measurement of the mass difference and relative production rate of the Ωb− and Ξb− baryons
The mass difference between the
Ω
−
b
and
Ξ
−
b
baryons is measured using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of
9
fb
−
1
, and is found to be
m
(
Ω
−
b
)
−
m
(
Ξ
−
b
)
=
248.54
±
0.51
(
stat
)
±
0.38
(
syst
)
MeV
/
c
2
. The mass of the
Ω
−
b
baryon is measured to be
m
(
Ω
−
b
)
=
6045.9
±
0.5
(
stat
)
±
0.6
(
syst
)
MeV
/
c
2
. This is the most precise determination of the
Ω
−
b
mass to date. In addition, the production rate of
Ω
−
b
baryons relative to that of
Ξ
−
b
baryons is measured for the first time in
p
p
collisions, using an LHCb dataset collected at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of
6
fb
−
1
. Reconstructing beauty baryons in the kinematic region
2
<
η
<
6
and
p
T
<
20
GeV
/
c
with their decays to a
J
/
ψ
meson and a hyperon, the ratio
f
Ω
−
b
f
Ξ
−
b
×
B
(
Ω
−
b
→
J
/
ψ
Ω
−
)
B
(
Ξ
−
b
→
J
/
ψ
Ξ
−
)
=
0.120
±
0.008
(
stat
)
±
0.008
(
syst
)
, is obtained, where
f
Ω
−
b
and
f
Ξ
−
b
are the fragmentation fractions of
b
quarks into
Ω
−
b
and
Ξ
−
b
baryons, respectively, and
B
represents the branching fractions of their respective decays
A uniform, quality controlled Surface Ocean CO2 Atlas (SOCAT)
A well documented, publicly available, global data set of surface ocean carbon dioxide (CO2) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO2, which had been subject to quality control (QC). Many additional CO2 data, not yet made public via the Carbon Dioxide Information Analysis Center (CDIAC), were retrieved from data originators, public websites and other data centres. All data were put in a uniform format following a strict protocol. Quality control was carried out according to clearly defined criteria. Regional specialists performed the quality control, using state-of-the-art web-based tools, specially developed for accomplishing this global team effort. SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO2 data points from the global oceans and coastal seas, spanning four decades (1968–2007). Three types of data products are available: individual cruise files, a merged complete data set and gridded products. With the rapid expansion of marine CO2 data collection and the importance of quantifying net global oceanic CO2 uptake and its changes, sustained data synthesis and data access are priorities
A Novel Approach for Shot Boundary Detection in Videos
This paper presents a novel approach for video shot boundary detection. The proposed approach is based on split and merge concept. A fisher linear discriminant criterion is used to guide the process of both splitting and merging. For the purpose of capturing the between class and within class scatter we employ 2D2 FLD method which works on texture feature of regions in each frame of a video. Further to reduce the complexity of the process we propose to employ spectral clustering to group related regions together to a single there by achieving reduction in dimension. The proposed method is experimentally also validated on a cricket video. It is revealed that shots obtained by the proposed approach are highly cohesive and loosely coupled
Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory
The Advanced LIGO and Advanced Virgo observatories recently discovered
gravitational waves from a binary neutron star inspiral. A short gamma-ray
burst (GRB) that followed the merger of this binary was also recorded by the
Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anticoincidence Shield for
the Spectrometer for the International Gamma-Ray Astrophysics Laboratory
(INTEGRAL), indicating particle acceleration by the source. The precise
location of the event was determined by optical detections of emission
following the merger. We searched for high-energy neutrinos from the merger in
the GeV--EeV energy range using the ANTARES, IceCube, and Pierre Auger
Observatories. No neutrinos directionally coincident with the source were
detected within s around the merger time. Additionally, no MeV
neutrino burst signal was detected coincident with the merger. We further
carried out an extended search in the direction of the source for high-energy
neutrinos within the 14-day period following the merger, but found no evidence
of emission. We used these results to probe dissipation mechanisms in
relativistic outflows driven by the binary neutron star merger. The
non-detection is consistent with model predictions of short GRBs observed at a
large off-axis angle.Comment: 22 pages, 2 figure