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A resistive-MicroMeGaS quadruplet built at CERN has been installed at the new CERN Gamma Irradiation Facility (GIF++) with the aim of carrying out a long-term ageing study. Two smaller resistive bulk-MicroMeGaS produced at the CERN PCB workshop have also been installed at GIF++ in order to provide a comparison of the ageing behavior with the MicroMeGaS quadruplet. We give an overview of the ongoing tests at GIF++ in terms of particle rate, integrated charge and spatial resolution of the MicroMeGaS detectors.

Background:Giant Cell Arteritis (GCA) and Takayasu Arteritis (TAK) are two systemic granulomatous vasculitis included in the group of large vessel vasculitis (LVV) Extracranial phenotype is characterized by large vessels (LV-GCA) involvement, mainly aorta or its main branches. Characteristically isolated extracranial LV-GCA phenotype is more like TAK disease. Tocilizumab (TCZ) seems to be an effective therapy for both diseases [1,2]. Nevertheless, no comparative studies on the effectiveness and safety of TCZ in GCA and TAK have been performed.Objectives:To compare the effectiveness and safety of TCZ in LV-GCA and TAK.Methods:A comparative observational national, open-label and multicenter study in patients diagnosed with LV-GCA (n=70) and TAK (n=57) patients who had received TCZ therapy. The diagnosis of GCA was made according to the 1990 criteria of the American College of Rheumatology (ACR). Patients with TAK were diagnosed according to the ACR 1990 criteria and/or Ishikawa criteria modified. Most patients were followed for at least 1 year since the TCZ onset. Follow-up visits were arranged at 1, 3, 6 and 12 months after TCZ initiation and outcome variables included: a) clinical remission and laboratory markers improvement; b) imaging improvement; c) GC-sparing effect; and d) safety analysis.Results:At TCZ initiation, TAK patients were younger, mainly female gender, with a longer disease duration, prior exposure to more biologics, and were on higher prednisone doses (Table 1). Although an initial slower clinical remission was observed in TAK patients, similar rates were observed at 12 months. Remission was observed in 35 (75.5%) and 30 (76.9%) LV-GCA and TAK, respectively, while complete imaging remission was achieved in 18.9% and 21.1% (Figure 1A). Similarly, CRP significantly decreased, during follow-up (Figures 1B). In this line, no differences were found in ESR and CRP between both groups in every visit and at the end of follow-up. Prednisone dose in every visit was found to be different between both diseases (Figure 1C). In this regard, TAK patients disclosed higher doses of GC in every visit and at the end of follow-up. In the mixed-models analysis, prednisone dose during follow-up was significantly different between both conditions (p<0.001). Safety data were similar in both groups. TCZ discontinuation due to severe infections occurred in 4 LV-GCA and 3 TAK patients.Conclusion:In a real-world setting TCZ showed comparable effectiveness in achieving remission and GC-sparing effects in LV-GCA and TAK. A discordance between clinical and imaging activity improvement was observed in both groups.REFERENCES:[1] Loricera J, Blanco R, Hernández JL, Castañeda S, Mera A, Pérez-Pampín E, et al. Tocilizumab in giant cell arteritis: Multicenter open-label study of 22 patients. Semin Arthritis Rheum. 2015;44(6).[2] Prieto-Peña D, Bernabeu P, Vela P, Narváez J, Fernández-López JC, Freire-González M, et al. Tocilizumab in refractory Caucasian Takayasu’s arteritis: a multicenter study of 54 patients and literature review. Ther Adv Musculoskelet Dis. 2021;13.Acknowledgements:NIL.Disclosure of Interests:Carmen Lasa-Teja: None declared, Javier Loricera Roche, Novartis, UCB Pharma, MSD, Janssen, Galápagos, Celgene, Astra Zeneca and Grünenthal., Janssen, Abbvie, Roche, Novartis, MSD, UCB Pharma, Celgene, Lilly, Pfizer, Galápagos., Diana Prieto-Peña UCB Pharma, Roche, Sanofi, Pfizer, Janssen, Amgen, AbbVie, Novartis and Lilly., Fernando López-Gutiérrez: None declared, Pilar Bernabéu: None declared, Mercedes Freire González: None declared, Beatriz González-Alvarez: None declared, Roser Solans-Laqué: None declared, Mauricio Minguez Abbvie, Janssen, GSK, Faes Farma and Novartis., Iván Ferraz-Amaro: None declared, Santos Castañeda BMS, Eli-Lilly, MSD, Roche, and UCB, MSD and Pfizer, Ricardo Blanco AbbVie, Pfizer, Roche, Bristol-Myers, Lilly, Galapagos, Novartis, Janssen, GSK, and MSD., AbbVie, MSD, and Roche.

Two searches for new phenomena in final states containing a same-flavour opposite-sign lepton (electron or muon) pair, jets, and large missing transverse momentum are presented. These searches make use of proton–proton collision data, collected during 2015 and 2016 at a centre-of-mass energy s√=13 TeV by the ATLAS detector at the large hadron collider, which correspond to an integrated luminosity of 14.7 fb−1. Both searches target the pair production of supersymmetric particles, squarks or gluinos, which decay to final states containing a same-flavour opposite-sign lepton pair via one of two mechanisms: a leptonically decaying Z boson in the final state, leading to a peak in the dilepton invariant-mass distribution around the Z boson mass; and decays of neutralinos (e.g. χ~02→ℓ+ℓ−χ~01), yielding a kinematic endpoint in the dilepton invariant-mass spectrum. The data are found to be consistent with the Standard Model expectation. Results are interpreted in simplified models of gluino-pair (squark-pair) production, and provide sensitivity to gluinos (squarks) with masses as large as 1.70 TeV (980 GeV).

This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of [radical]s = 7 TeV and correspond to an integrated luminosity of 4.6 fb super(-1). The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum p sub(T) > 320 GeV and pseudorapidity |[eta]| < 1.9, is measured to be [sigma] sub()W+ Z= 8.5 + or - 1.7 pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques.

A likelihood-based discriminant for the identification of quark- and gluon-initiated jets is built and validated using 4.7 fb[Formula: see text] of proton-proton collision data at [Formula: see text] [Formula: see text] collected with the ATLAS detector at the LHC. Data samples with enriched quark or gluon content are used in the construction and validation of templates of jet properties that are the input to the likelihood-based discriminant. The discriminating power of the jet tagger is established in both data and Monte Carlo samples within a systematic uncertainty of [Formula: see text] 10-20 %. In data, light-quark jets can be tagged with an efficiency of [Formula: see text] while achieving a gluon-jet mis-tag rate of [Formula: see text] in a [Formula: see text] range between [Formula: see text] and [Formula: see text] for jets in the acceptance of the tracker. The rejection of gluon-jets found in the data is significantly below what is attainable using a Pythia 6 Monte Carlo simulation, where gluon-jet mis-tag rates of 10 % can be reached for a 50 % selection efficiency of light-quark jets using the same jet properties.

The integrated elliptic flow of charged particles produced in Pb+Pb collisions at [Formula: see text] TeV has been measured with the ATLAS detector using data collected at the Large Hadron Collider. The anisotropy parameter, [Formula: see text], was measured in the pseudorapidity range [Formula: see text] with the event-plane method. In order to include tracks with very low transverse momentum [Formula: see text], thus reducing the uncertainty in [Formula: see text] integrated over [Formula: see text], a [Formula: see text] data sample recorded without a magnetic field in the tracking detectors is used. The centrality dependence of the integrated [Formula: see text] is compared to other measurements obtained with higher [Formula: see text] thresholds. The integrated elliptic flow is weakly decreasing with [Formula: see text]. The integrated [Formula: see text] transformed to the rest frame of one of the colliding nuclei is compared to the lower-energy RHIC data.

Abstract The CMS detector, including its muon system, has been operating at the CERN LHC in increasingly challenging conditions for about 15 years. The muon detector was designed to provide excellent triggering and track reconstruction for muons produced in proton–proton collisons at an instantaneous luminosity (𝓛L ) of1 × 10³⁴1 × 10 34  cm⁻²- 2 s⁻¹- 1 . During the Run 2 data-taking period (2015–2018), the LHC achieved an instantaneous luminosity of twice its design value, resulting in larger background rates and making the efficient detection of muons more difficult. While some backgrounds result from natural radioactivity, cosmic rays, and interactions of the circulating protons with residual gas in the beam pipe, the dominant source of background hits in the muon system arises from proton–proton interactions themselves. Charged hadrons leaving the calorimeters produce energy deposits in the muon chambers. In addition, high-energy particles interacting in the hadron calorimeter and forward shielding elements generate thermal neutrons, which leak out of the calorimeter and shielding structures, filling the CMS cavern. We describe the method used to measure the background rates in the various muon subsystems. These rates, in conjunction with simulations, can be used to estimate the expected backgrounds in the High-Luminosity LHC. This machine will run for at least 10 years starting in 2029 reaching an instantaneous luminosity of𝓛 = 5 × \\text 10^(\\text) 34 \\text cm^(\\text) -2 \\text s^(\\text) -1L = 5 × 10 34 cm -2 s -1 and increasing ultimately to𝓛 = 7.5 × \\text 10^(\\text) 34 \\text cm^(\\text) -2 \\text s^(\\text) -1L = 7.5 × 10 34 cm -2 s -1 . These background estimates have been a key ingredient for the planning and design of the muon detector upgrade.

This paper presents a measurement of the W boson production cross section and the W+/W-cross-section ratio, both in association with jets, in proton-proton collisions at s=8 TeV with the ATLAS experiment at the Large Hadron Collider. The measurement is performed in final states containing one electron and missing transverse momentum using data corresponding to an integrated luminosity of 20.2 fb-1. Differential cross sections for events with at least one or two jets are presented for a range of observables, including jet transverse momenta and rapidities, the scalar sum of transverse momenta of the visible particles and the missing transverse momentum in the event, and the transverse momentum of the W boson. For a subset of the observables, the differential cross sections of positively and negatively charged W bosons are measured separately. In the cross-section ratio of W+/W- the dominant systematic uncertainties cancel out, improving the measurement precision by up to a factor of nine. The observables and ratios selected for this paper provide valuable input for the up quark, down quark, and gluon parton distribution functions of the proton.[Figure not available: see fulltext.].