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Search for resonant production of dark quarks in the dijet final state with the ATLAS detector
No full textThis paper presents a search for a new Z′ resonance decaying into a pair of dark quarks which hadronise into dark hadrons before promptly decaying back as Standard Model particles. This analysis is based on proton-proton collision data recorded at = 13 TeV with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to an integrated luminosity of 139 fb. After selecting events containing large-radius jets with high track multiplicity, the invariant mass distribution of the two highest-transverse-momentum jets is scanned to look for an excess above a data-driven estimate of the Standard Model multijet background. No significant excess of events is observed and the results are thus used to set 95% confidence-level upper limits on the production cross-section times branching ratio of the Z′ to dark quarks as a function of the Z′ mass for various dark-quark scenarios.[graphic not available: see fulltext
The second data release from the European Pulsar Timing Array - V. Search for continuous gravitational wave signals
No full textWe present the results of a search for continuous gravitational wave signals (CGWs) in the second data release (DR2) of the European Pulsar Timing Array (EPTA) Collaboration. The most significant candidate event from this search has a gravitational wave frequency of 4–5 nHz. Such a signal could be generated by a supermassive black hole binary (SMBHB) in the local Universe. We present the results of a follow-up analysis of this candidate using both Bayesian and frequentist methods. The Bayesian analysis gives a Bayes factor of 4 in favour of the presence of the CGW over a common uncorrelated noise process. In contrast, the frequentist analysis estimates the p-value of the candidate to be < 1%, also assuming the presence of common uncorrelated red noise. However, comparing a model that includes both a CGW and a gravitational wave background (GWB) to a GWB only, the Bayes factor in favour of the CGW model is only 0.7. Therefore, we cannot conclusively determine the origin of the observed feature, nor can we rule it out as a CGW source. We present results of simulations that demonstrate that data containing a weak gravitational wave background can be misinterpreted as data including a CGW and vice versa, providing two plausible explanations for the EPTA DR2 data. Further investigations combining data from all PTA collaborations will be needed to reveal the true origin of this feature.Key words: gravitational waves / methods: data analysis / pulsars: general⋆ Corresponding authors; [email protected], [email protected], [email protected]
Measurement of the Z boson production cross-section in pp collisions at = 5.02 TeV
No full textThe first measurement of the Z boson production cross-section at centre-of-mass energy = 5.02 TeV in the forward region is reported, using pp collision data collected by the LHCb experiment in year 2017, corresponding to an integrated luminosity of 100 ± 2 pb. The production cross-section is measured for final-state muons in the pseudorapidity range 2.0 < η < 4.5 with transverse momentum p> 20 GeV/c. The integrated cross-section is determined to befor the di-muon invariant mass in the range 60 < M< 120 GeV/c. This result and the differential cross-section results are in good agreement with theoretical predictions at next-to-next-to-leading order in the strong coupling constant.Based on a previous LHCb measurement of the Z boson production cross-section in pPb collisions at = 5.02 TeV, the nuclear modification factor R is measured for the first time at this energy. The measured values are (stat) ± 0.1(syst) in the forward region (1.53 << 4.03) and (stat) ± 0.2(syst) in the backward region (−4.97 << −2.47), where represents the muon rapidity in the centre-of-mass frame.[graphic not available: see fulltext][graphic not available: see fulltext
Observation of significant flavor-SU(3) breaking in the kaon wave function at and discovery of the charmless decay
No full textWe present cross sections for the reaction at center-of-mass energies ranging from 3.51 GeV to 4.95 GeV using data samples collected in the BESIII experiment, corresponding to a total integrated luminosity of 26.5 fb. The ratio of neutral-to-charged kaon form factors at large momentum transfers (12~{\rm GeV}^2<Q^2<25~{\rm GeV}^2) is determined to be , which indicates a small but significant effect of flavor-SU(3) breaking in the kaon wave function, and consequently excludes the possibility that flavor-SU(3) breaking is the primary reason for the strong experimental violation of the pQCD prediction , where and are the form factors, and and are the decay constants of charged pions and kaons, respectively. We also observe a significant signal for the charmless decay for the first time. Within a contour of the likelihood value, the the branching fraction for is determined to be , and the relative phase between the continuum and amplitudes is . The branching fraction is in good agreement with the - and -wave charmonia mixing scheme proposed in the interpretation of the " puzzle" between and decays
Measurement of t-channel single-top-quark production in pp collisions at <math altimg="si1.svg"><msqrt><mrow><mi>s</mi></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>5.02</mn></math> TeV with the ATLAS detector
No full textThe observation of the electroweak production of single-top-quarks is made using 255 pb−1 of proton-proton collision data recorded at s=5.02 TeV with the ATLAS detector at the Large Hadron Collider. An event selection is used to identify single-top-quark candidates arising from t-channel production with the top quark decaying semi-leptonically. Events passing the selection are then used to measure the inclusive cross-section for the combined production of single-top-quarks and antiquarks, σ(tq+t¯q), and the ratio Rt between these two. They are measured to be σ(tq+t¯q)=27.1−4.1+4.4(stat.)−3.7+4.4(syst.) pb and Rt=2.73−0.82+1.43(stat.)−0.29+1.01(syst.). The individual single-top-quark (tq) and single-top-antiquark (t¯q) production cross-sections are measured to be σ(tq)=19.8−3.1+3.9(stat.)−2.2+2.9(syst.) pb and σ(t¯q)=7.3−2.1+3.2(stat.)−1.5+2.8(syst.) pb. All measurements are in good agreement with the Standard Model predictions
Measurements of jet quenching using semi-inclusive hadron+jet distributions in <math><mrow><mi>p</mi><mi>p</mi></mrow></math> and central Pb-Pb collisions at <math><mrow><msqrt><msub><mi>s</mi><mrow><mi>N</mi><mi>N</mi></mrow></msub></msqrt><mo>=</mo><mn>5.02</mn></mrow></math> TeV
No full textThe ALICE Collaboration reports measurements of the semi-inclusive distribution of charged-particle jets recoiling from a high transverse momentum (high pT) charged hadron, in pp and central Pb-Pb collisions at center-of-mass energy per nucleon–nucleon collision sNN=5.02 TeV. The large uncorrelated background in central Pb-Pb collisions is corrected using a data-driven statistical approach which enables precise measurement of recoil jet distributions over a broad range in pT,chjet and jet resolution parameter R. Recoil jet yields are reported for R=0.2, 0.4, and 0.5 in the range 7<pT,chjet<140 GeV/c and π/2<Δφ<π, where Δφ is the azimuthal angular separation between hadron trigger and recoil jet. The low-pT,chjet reach of the measurement explores unique phase space for studying jet quenching, the interaction of jets with the quark–gluon plasma generated in high-energy nuclear collisions. Comparison of pT,chjet distributions from pp and central Pb-Pb collisions probes medium-induced jet energy loss and intra-jet broadening, while comparison of their acoplanarity distributions explores in-medium jet scattering and medium response. The measurements are compared to theoretical calculations incorporating jet quenching
The LHCb Upgrade I
No full textThe LHCb upgrade represents a major change of theexperiment. The detectors have been almost completely renewed toallow running at an instantaneous luminosity five times larger thanthat of the previous running periods. Readout of all detectors intoan all-software trigger is central to the new design, facilitatingthe reconstruction of events at the maximum LHC interaction rate,and their selection in real time. The experiment's tracking systemhas been completely upgraded with a new pixel vertex detector, asilicon tracker upstream of the dipole magnet and threescintillating fibre tracking stations downstream of the magnet. Thewhole photon detection system of the RICH detectors has been renewedand the readout electronics of the calorimeter and muon systems havebeen fully overhauled. The first stage of the all-software triggeris implemented on a GPU farm. The output of the trigger provides acombination of totally reconstructed physics objects, such as tracksand vertices, ready for final analysis, and of entire events whichneed further offline reprocessing. This scheme required a completerevision of the computing model and rewriting of the experiment'ssoftware
Measurement of ZZ production cross-sections in the four-lepton final state in pp collisions at <math altimg="si1.svg"><msqrt><mrow><mi>s</mi></mrow></msqrt><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>13.6</mn><mspace width="0.25em"/><mtext>TeV</mtext></math> with the ATLAS experiment
No full textThis paper reports cross-section measurements of ZZ production in pp collisions at s=13.6TeV at the Large Hadron Collider. The data were collected by the ATLAS detector in 2022, and correspond to an integrated luminosity of 29 fb<sup>−1</sup>. Events in the ZZ→4ℓ (ℓ=e, μ) final states are selected and used to measure the inclusive and differential cross-sections in a fiducial region defined close to the analysis selections. The inclusive cross-section is further extrapolated to the total phase space with a requirement of 66 <mZ< 116 GeV for both Z bosons, yielding 16.8±1.1 pb. The results are well described by the Standard Model predictions
Report on the Web Service Architecture and API endpoint description
Get PDF<p>The report describes the web service architecture deployed in HaMMon project task 2.3.</p>\n\n<p>Task2.3: Development of a web service to expose 3D models to third-party applications The task focuses on the development of a web service that exposes 3D models to applications used by claims adjusters. It involves identifying the requirements, designing the service architecture, developing the API, implementing the 3D model processing and storage functionality, and testing the service to ensure it meets the requirements and works seamlessly with third-party applications.</p>
Datawarehouse della Direzione Sistemi Informativi INFN: Aggiornamenti alla Struttura dell'ETL
Get PDF<p>L’ETL (Extract, Transform, Load) è il processo che, in notturna, si occupa di aggiornare la banca dati del Data Warehouse INFN al fine di esporre agli utenti dati consistenti e certificati tramite strumenti di Business Intelligence (BI). </p>\n\n<p>Essendo un processo complesso e articolato, la sua esecuzione tramite un tool dedicato richiede molto tempo, eppure è fondamentale per la certificazione dei dati da rendere fruibili tramite report e dashboard. </p>\n\n<p>Uno degli obiettivi dell’Ufficio Data Warehouse e Business Intelligence della Direzione Sistemi Informativi (DSI) è quello mantenere ed evolvere questo processo, migliorarne le performance ed occuparsi della correttezza, completezza e consistenza del contenuto informativo della banca dati. </p>\n\n<p>Questa nota tecnica si concentra sull’evoluzione dell'architettura di ETL.</p>