Beauty and charm quarks are ideal probes of pertubative Quantum Chromodymanics in proton–proton collisions, owing to their large masses. In this paper the role of multi-parton interactions in the ...production of doubly-heavy hadrons is studied using simulation samples generated with
Pythia
, a Monte Carlo event generator. Comparisons are made to the stand-alone generators
BcVegPy
and
GenXicc
. New methods of speeding up
Pythia
simulations for events containing heavy quarks are described, enabling the production of large samples with multiple heavy-quark pairs. We show that significantly higher production rates of doubly-heavy hadrons are predicted in models that allow heavy quarks originating from different parton–parton interactions (within the same hadron–hadron collision) to combine to form such hadrons. Quantitative predictions are sensitive to the modelling of colour reconnections. We suggest a set of experimental measurements capable of differentiating these additional contributions.
Weak decays of the vector
D
∗
0
and
B
(
s
)
∗
0
mesons to the
μ
+
μ
-
final state provide novel potential to test the Standard Model of particle physics. Such processes have extremely small branching ...fractions as the vector mesons are able to decay through electromagnetic and (for the
D
∗
0
meson) strong interactions. Nonetheless, the production of copious quantities of these particles in LHC collisions, and the ability to exploit experimental techniques that can suppress background to low levels, provides good potential to reach interesting sensitivity. The possibility to reconstruct these processes as part of the decay chain of
B
-
or
B
c
+
mesons appears particularly attractive due to the clean experimental signature of the displaced vertex. Indeed, published LHCb data on
B
-
→
π
-
μ
+
μ
-
decays already implies a stringent limit on the branching fraction of
D
∗
0
→
μ
+
μ
-
. Estimates are made on the achievable sensitivity to
D
∗
0
→
μ
+
μ
-
and
B
(
s
)
∗
0
→
μ
+
μ
-
decays with the LHCb experiment.
A Feed Forward Neural Net (NN) approach to distinguish between clouds and the surface has been applied to the Sea and Land Surface Temperature Radiometer in polar regions. The masking algorithm ...covers the Arctic, Antarctic and regions typically classified as the cryosphere such as northern hemisphere permafrost. The mask has been trained using collocations with the CALIOP active lidar, which in narrow strips provide more accurate detection of cloud, and was subsequently evaluated as a function of cloud type and surface type. The mask was compared with the existing operational Bayesian and Empirical cloud masks by eye and also statistically using CALIOP data. It was found to perform exceptionally well in the polar regions. The Kuiper skill score improved from 0.28, for the operational Bayesian and 0.17 for the Empirical masks to 0.77 for the NN. The NN algorithm also has a much more homogeneous performance over all surface types. The key improvement came from better identification of clear scenes; for the NN mask, the same performance in terms of contamination of cloudy pixels in the sample of identified clear pixels can be achieved while retaining 40% of the clear pixels compared with 10% for the operational cloud identification. The algorithm performed with almost the same skill over sea and land. The best performance was achieved for opaque clouds while transparent and broken clouds showed slightly reduced accuracy.
•Machine learning algorithm for SLSTR cloud masking•SLSTR cloud masking using collocated pixels with CALIOP for training dataset•Comparison made to existing operational cloud masks in polar regions•Algorithm can identify 4 times larger clear areas in the polar regions•Almost uniform performance of cloud masking across land and sea
Abstract A method for analysing the hadronic resonance contributions in $$\overline{B}{} ^0 \!\rightarrow \overline{K}{} ^{*0} \mu ^+ \mu ^- $$ B¯0→K¯∗0μ+μ- decays is presented. This method uses an ...empirical model that relies on measurements of the branching fractions and polarisation amplitudes of final states involving $$J^{PC}=1^{--}$$ JPC=1-- resonances, relative to the short-distance component, across the full dimuon mass spectrum of $$\overline{B}{} ^0 \!\rightarrow \overline{K}{} ^{*0} \mu ^+ \mu ^- $$ B¯0→K¯∗0μ+μ- transitions. The model is in good agreement with existing calculations of hadronic non-local effects. The effect of this contribution to the angular observables is presented and it is demonstrated how the narrow resonances in the $$q^2 $$ q2 spectrum provide a dramatic enhancement to $$C\!P$$ CP -violating effects in the short-distance amplitude. Finally, a study of the hadronic resonance effects on lepton universality ratios, $$R_{K^{(*)}}$$ RK(∗) , in the presence of new physics is presented.
A method for analysing the hadronic resonance contributions in
B
¯
0
→
K
¯
∗
0
μ
+
μ
-
decays is presented. This method uses an empirical model that relies on measurements of the branching fractions ...and polarisation amplitudes of final states involving
J
PC
=
1
-
-
resonances, relative to the short-distance component, across the full dimuon mass spectrum of
B
¯
0
→
K
¯
∗
0
μ
+
μ
-
transitions. The model is in good agreement with existing calculations of hadronic non-local effects. The effect of this contribution to the angular observables is presented and it is demonstrated how the narrow resonances in the
q
2
spectrum provide a dramatic enhancement to
C
P
-violating effects in the short-distance amplitude. Finally, a study of the hadronic resonance effects on lepton universality ratios,
R
K
(
∗
)
, in the presence of new physics is presented.
This paper reports world averages of measurements of b-hadron, c-hadron, and τ-lepton properties obtained by the Heavy Flavour Averaging Group using results available through September 2018. In rare ...cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays, and Cabibbo–Kobayashi–Maskawa matrix elements.
This document presents the result of recent developments within Ganga1 project to support users from new communities outside of HEP. In particular I will examine the case of users from the Large ...Scale Survey Telescope (LSST) group looking to use resources provided by the UK based GridPP23 DIRAC45 instance. An example use case is work performed with users from the LSST Virtual Organisation (VO) to distribute the workflow used for galaxy shape identification analyses. This work highlighted some LSST specific challenges which could be well solved by common tools within the HEP community. As a result of this work the LSST community was able to take advantage of GridPP23 resources to perform large computing tasks within the UK.
In this paper, we present the computational task-management tool Ganga, which allows for the specification, submission, bookkeeping and post-processing of computational tasks on a wide set of ...distributed resources. Ganga has been developed to solve a problem increasingly common in scientific projects, which is that researchers must regularly switch between different processing systems, each with its own command set, to complete their computational tasks. Ganga provides a homogeneous environment for processing data on heterogeneous resources. We give examples from High Energy Physics, demonstrating how an analysis can be developed on a local system and then transparently moved to a Grid system for processing of all available data. Ganga has an API that can be used via an interactive interface, in scripts, or through a GUI. Specific knowledge about types of tasks or computational resources is provided at run-time through a plugin system, making new developments easy to integrate. We give an overview of the Ganga architecture, give examples of current use, and demonstrate how Ganga can be used in many different areas of science.
Program title:Ganga
Catalogue identifier: AEEN_v1_0
Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEN_v1_0.html
Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland
Licensing provisions: GPL
No. of lines in distributed program, including test data, etc.: 224 590
No. of bytes in distributed program, including test data, etc.: 14 365 315
Distribution format: tar.gz
Programming language: Python
Computer: personal computers, laptops
Operating system: Linux/Unix
RAM: 1 MB
Classification: 6.2, 6.5
Nature of problem: Management of computational tasks for scientific applications on heterogenous distributed systems, including local, batch farms, opportunistic clusters and Grids.
Solution method: High-level job management interface, including command line, scripting and GUI components.
Restrictions: Access to the distributed resources depends on the installed, 3rd party software such as batch system client or Grid user interface.
This paper reports world averages of measurements of
b
-hadron,
c
-hadron, and
τ
-lepton properties obtained by the Heavy Flavour Averaging Group using results available through September 2018. In ...rare cases, significant results obtained several months later are also used. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters,
C
P
violation parameters, parameters of semileptonic decays, and Cabibbo–Kobayashi–Maskawa matrix elements.
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