A
bstract
This report details the capabilities of LHCb and its upgrades towards the study of kaons and hyperons. The analyses performed so far are reviewed, elaborating on the prospects for some key ...decay channels, while proposing some new measurements in LHCb to expand its strangeness research program.
We describe a fully GPU-based implementation of the first level trigger for the upgrade of the LHCb detector, due to start data taking in 2021. We demonstrate that our implementation, named Allen, ...can process the 40 Tbit/s data rate of the upgraded LHCb detector and perform a wide variety of pattern recognition tasks. These include finding the trajectories of charged particles, finding proton–proton collision points, identifying particles as hadrons or muons, and finding the displaced decay vertices of long-lived particles. We further demonstrate that Allen can be implemented in around 500 scientific or consumer GPU cards, that it is not I/O bound, and can be operated at the full LHC collision rate of 30 MHz. Allen is the first complete high-throughput GPU trigger proposed for a HEP experiment.
A search for the decays Bs0 → e+e− and B0 → e+e− is performed using data collected with the LHCb experiment in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV, corresponding ...to integrated luminosities of 1, 2, and 2 fb − 1 , respectively. No signal is observed. Assuming no contribution from B0 → e+e− decays, an upper limit on the branching fraction B (Bs0 → e+e−) < 9.4 ( 11.2 ) × 10−9 is obtained at 90(95)% confidence level. If no Bs0 → e+e− contribution is assumed, a limit of B (B0 → e+e−) < 2.5 ( 3.0 ) × 10−9 is determined at 90(95)% confidence level. These upper limits are more than one order of magnitude lower than the previous
The ratio of the B0s and B+ fragmentation fractions fs and fu is studied with B0s → J/ψ ϕ and B+ → J/ψK+ decays using data collected by the LHCb experiment in proton-proton collisions at 7, 8, and 13 ...TeV center-of-mass energies. The analysis is performed in bins of B -meson momentum, longitudinal momentum, transverse momentum, pseudorapidity, and rapidity. The fragmentation-fraction ratio fs/fu is observed to depend on the B -meson transverse momentum with a significance of 6.0σ . This dependency is driven by the 13 TeV sample (8.7σ), while the results for the other collision energies are not significant when considered separately. Furthermore, the results show a 4.8σ evidence for an increase of fs/fu as a function of collision energy.
This report details the capabilities of LHCb and its upgrades towards the study of kaons and hyperons. The analyses performed so far are reviewed, elaborating on the prospects for some key decay ...channels, while proposing some new measurements in LHCb to expand its strangeness research program.
We describe a fully GPU-based implementation of the first level trigger for the upgrade of the LHCb detector, due to start data taking in 2021. We demonstrate that our implementation, named Allen, ...can process the 40 Tbit/s data rate of the upgraded LHCb detector and perform a wide variety of pattern recognition tasks. These include finding the trajectories of charged particles, finding proton-proton collision points, identifying particles as hadrons or muons, and finding the displaced decay vertices of long-lived particles. We further demonstrate that Allen can be implemented in around 500 scientific or consumer GPU cards, that it is not I/O bound, and can be operated at the full LHC collision rate of 30 MHz. Allen is the first complete high-throughput GPU trigger proposed for a HEP experiment.
ALP–mediated decays and other as-yet unobserved B decays to di-photon
final states are a challenge to select in hadron collider environments
due to the large backgrounds that come directly from the ...pp collision.
We present the strategy implemented by the LHCb experiment in 2018 to
efficiently select such photon pairs. A fast neural network topology,
implemented in the LHCb real-time selection framework achieves high
efficiency across a mass range of
4–20GeV/c
^2
2
.
We discuss implications and future prospects for the LHCb
experiment.
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