Towards the ALICE Online-Offline (O2^2) control system

The ALICE Experiment at CERN LHC (Large Hadron Collider) is under preparation for a major upgrade that is scheduled to be deployed during Long Shutdown 2 in 2019-2020 and that includes new computing systems, called O$^2$ (Online-Offline). To ensure the efficient operation of the upgraded experiment along with its newly designed computing system, a reliable, high performance and automated control system will be developed with the goal of managing the lifetime of all the O$^2$ processes, and of handling the various phases of the data taking activity by interacting with the detectors, the trigger system and the LHC. The ALICE O$^2$ control system will be a distributed system based on state of the art cluster management and microservices which have recently emerged in the distributed computing ecosystem. Such technologies weren’t available during the design and development of the original LHC computing systems, and their use will allow the ALICE collaboration to benefit from a vibrant and innovating open source community. This paper illustrates the O$^2$ control system architecture. It evaluates several solutions that were considered during an initial prototyping phase and provides a rationale for the choices made. It also provides an in-depth overview of the components, features and design elements of the actual system

Towards The Alice Online-Offline (O2) Control System

The ALICE Experiment at CERN LHC (Large Hadron Collider) is under preparation for a major upgrade that is scheduled to be deployed during Long Shutdown 2 in 2019-2020 and that includes new computing systems, called O2 (Online-Offine). To ensure the efficient operation of the upgraded experiment along with its newly designed computing system, a reliable, high performance and automated control system will be developed with the goal of managingthe lifetime of all the O2 processes, and of handling the various phases of the data taking activity by interacting with the detectors, the trigger system and the LHC. The ALICE O2 control system will be a distributed systembased on state of the art cluster management and microservices which have recently emerged in the distributed computing ecosystem. Such technologies weren’t available during the design and development of the original LHC computing systems, and their use will allow the ALICE collaboration to benefit from a vibrant and innovatingopen source community. This paper illustrates the O2 control system architecture. It evaluates several olutionsthat were considered during an initial prototyping phase and provides a rationale for the choices made. It also provides an in-depth overview of the components, features and design elements of the actual system

AliECS: a New Experiment Control System for the ALICE Experiment

The ALICE Experiment at CERN’s Large Hadron Collider (LHC) is undertaking a major upgrade during LHC Long Shutdown 2 in 2019-2021, which includes a new computing system called O2 (Online-Offline). To ensure the efficient operation of the upgraded experiment and of its newly designed computing system, a reliable, high performance, and automated experiment control system is being developed. The ALICE Experiment Control System (AliECS) is a distributed system based on state of the art cluster management and microservices that have recently emerged in the distributed computing ecosystem. Such technologies will allow the ALICE collaboration to benefit from a vibrant and innovating open source community. This communication describes the AliECS architecture. It provides an in-depth overview of the system’s components, features, and design elements, as well as its performance. It also reports on the experience with AliECS as part of ALICE Run 3 detector commissioning setups

AliECS: a New Experiment Control System for the ALICE Experiment

The ALICE Experiment at CERN’s Large Hadron Collider (LHC) is undertaking a major upgrade during LHC Long Shutdown 2 in 2019-2021, which includes a new computing system called O2 (Online-Offline). To ensure the efficient operation of the upgraded experiment and of its newly designed computing system, a reliable, high performance, and automated experiment control system is being developed. The ALICE Experiment Control System (AliECS) is a distributed system based on state of the art cluster management and microservices that have recently emerged in the distributed computing ecosystem. Such technologies will allow the ALICE collaboration to benefit from a vibrant and innovating open source community. This communication describes the AliECS architecture. It provides an in-depth overview of the system’s components, features, and design elements, as well as its performance. It also reports on the experience with AliECS as part of ALICE Run 3 detector commissioning setups

FairRootGroup/FairMQ: v1.3.8

[bug fixes] 291d00c Fix regression with ignored rateLogging channel argument 0cb8f61 Let getMessage deal with SSO [enhancement] 4dc37ef Allow implicit conversion factory->resourc

Multiplicity dependence of light (anti-)nuclei production in p–Pb collisions at sNN=5.02 TeV

The measurement of the deuteron and anti-deuteron production in the rapidity range −1 < y < 0 as a function of transverse momentum and event multiplicity in p–Pb collisions at √sNN = 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss dE/dx and via their time-of- flight. Their production in p–Pb collisions is compared to pp and Pb–Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and approaching those observed in Pb–Pb collisions at high multiplicities. The mean transverse particle momenta are extracted from the deuteron spectra and the values are similar to those obtained for p and particles. Thus, deuteron spectra do not follow mass ordering. This behaviour is in contrast to the trend observed for non-composite particles in p–Pb collisions. In addition, the production of the rare 3He and 3He nuclei has been studied. The spectrum corresponding to all non-single diffractive p-Pb collisions is obtained in the rapidity window −1 < y < 0 and the pT-integrated yield dN/dy is extracted. It is found that the yields of protons, deuterons, and 3He, normalised by the spin degeneracy factor, follow an exponential decrease with mass number

Pseudorapidity densities of charged particles with transverse momentum thresholds in pp collisions at √ s = 5.02 and 13 TeV

The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of √s=5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within 0.8pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η|2GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at √s=13TeV.

Measurement of inclusive J/ψ\psi pair production cross section in pp collisions at s=13\sqrt{s} = 13 TeV

International audienceThe production cross section of inclusive J/$\psi$ pairs in pp collisions at a centre-of-mass energy $\sqrt{s} = 13$ TeV is measured with ALICE. The measurement is performed for J/$\psi$ in the rapidity interval $2.5 0$. The production cross section of inclusive J/$\psi$ pairs is reported to be $10.3 \pm 2.3 {\rm (stat.)} \pm 1.3 {\rm (syst.)}$ nb in this kinematic interval. The contribution from non-prompt J/$\psi$ (i.e. originated from beauty-hadron decays) to the inclusive sample is evaluated. The results are discussed and compared with data

Inclusive and multiplicity dependent production of electrons from heavy-flavour hadron decays in pp and p−-Pb collisions

International audienceMeasurements of the production of electrons from heavy-flavour hadron decays in pp collisions at $\sqrt{s} = 13$ TeV at midrapidity with the ALICE detector are presented down to a transverse momentum ($p_{\rm T}$) of 0.2 GeV$/c$ and up to $p_{\rm T} = 35$ GeV$/c$, which is the largest momentum range probed for inclusive electron measurements in ALICE. In p$-$Pb collisions, the production cross section and the nuclear modification factor of electrons from heavy-flavour hadron decays are measured in the $p_{\rm T}$ range $0.5 < p_{\rm T} < 26$ GeV$/c$ at $\sqrt{s_{\rm NN}} = 8.16$ TeV. The nuclear modification factor is found to be consistent with unity within the statistical and systematic uncertainties. In both collision systems, first measurements of the yields of electrons from heavy-flavour hadron decays in different multiplicity intervals normalised to the multiplicity-integrated yield (self-normalised yield) at midrapidity are reported as a function of the self-normalised charged-particle multiplicity estimated at midrapidity. The self-normalised yields in pp and p$-$Pb collisions grow faster than linear with the self-normalised multiplicity. A strong $p_{\rm T}$ dependence is observed in pp collisions, where the yield of high-$p_{\rm T}$ electrons increases faster as a function of multiplicity than the one of low-$p_{\rm T}$ electrons. The measurement in p$-$Pb collisions shows no $p_{\rm T}$ dependence within uncertainties. The self-normalised yields in pp and p$-$Pb collisions are compared with measurements of other heavy-flavour, light-flavour, and strange particles, and with Monte Carlo simulations

Observation of medium-induced yield enhancement and acoplanarity broadening of low-pTp_\mathrm{T} jets from measurements in pp and central Pb−-Pb collisions at sNN=5.02\sqrt{s_{\rm NN}}=5.02 TeV

International audienceThe ALICE Collaboration reports the measurement of semi-inclusive distributions of charged-particle jets recoiling from a high transverse momentum (high $p_{\rm T}$) hadron trigger in proton$-$proton and central Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. A data-driven statistical method is used to mitigate the large uncorrelated background in central Pb$-$Pb collisions. Recoil jet distributions are reported for jet resolution parameter $R=0.2$, 0.4, and 0.5 in the range $7 < p_{\rm T,jet} < 140$ GeV$/c$ and trigger$-$recoil jet azimuthal separation $\pi/2 < \Delta\varphi < \pi$. The measurements exhibit a marked medium-induced jet yield enhancement at low $p_{\rm T}$ and at large azimuthal deviation from $\Delta\varphi\sim\pi$. The enhancement is characterized by its dependence on $\Delta\varphi$, which has a slope that differs from zero by 4.7$\sigma$. Comparisons to model calculations incorporating different formulations of jet quenching are reported. These comparisons indicate that the observed yield enhancement arises from the response of the QGP medium to jet propagation