Every year there are > 33 million cases of Respiratory Syncytial Virus (RSV)-related respiratory infection in children under the age of five, making RSV the leading cause of lower respiratory tract ...infection (LRTI) in infants. RSV is a global infection, but 99% of related mortality is in low/middle-income countries. Unbelievably, 62 years after its identification, there remains no effective treatment nor vaccine for this deadly virus, leaving infants, elderly and immunocompromised patients at high risk. The success of all pathogens depends on their ability to evade and modulate the host immune response. RSV has a complex and intricate relationship with our immune systems, but a clearer understanding of these interactions is essential in the development of effective medicines. Therefore, in a bid to update and focus our research community’s understanding of RSV’s interaction with immune defences, this review aims to discuss how our current knowledgebase could be used to combat this global viral threat.
The performance of superconducting radiofrequency (SRF) cavities used for particle accelerators depends on two characteristic material parameters: field of first flux entryHentryand pinning strength. ...The former sets the limit for the maximum achievable accelerating gradient, while the latter determines how efficiently flux can be expelled related to the maximum achievable quality factor. In this paper, a method based on muon spin rotation (μSR) is developed to probe these parameters on samples. It combines measurements from two different spectrometers, one being specifically built for these studies and samples of different geometries. It is found that annealing at1400°Cvirtually eliminates all pinning. Such an annealed substrate is ideally suited to measureHentryof layered superconductors, which might enable accelerating gradients beyond bulk niobium technology.
The inner tracker of the ATLAS detector is scheduled to be replaced by a completely new silicon-based inner tracker (ITk) for the Phase-II of the CERN LHC (HL-LHC). The silicon strip detector covers ...the volume 40<R<100 cm in the radial and |z|<300 cm in the longitudinal directions. The silicon sensors for the detector will be fabricated using the n+-on-p 6-inch wafer technology, for a total of 22,000 wafers. Intensive studies were carried out on the final prototype sensors ATLAS17LS fabricated by Hamamatsu Photonics (HPK). The charge collection properties were examined using penetrating 90Sr β-rays and the ALIBAVA fast readout system for the miniature sensors of 1 cm ×1 cm in area. The samples were irradiated by protons in the 27 MeV Birmingham Cyclotron, the 70 MeV CYRIC at Tohoku University, and the 24 GeV CERN-PS, and by neutrons at Ljubljana TRIGA reactor for fluence values up to 2 × 1015 neq/cm2. The change in the charge collection with fluence was found to be similar to the previous prototype ATLAS12, and acceptable for the ITk. Sensors with two active thicknesses, 300μm (standard) and 240μm (thin), were compared and the difference in the charge collection was observed to be small for bias voltages up to 500 V. Some samples were also irradiated with gamma radiation up to 2 MGy, and the full depletion voltage was found to decrease with the dose. This was caused by the Compton electrons due to the 60Co gamma radiation. To summarize, the design of the ATLAS17LS and technology for its fabrication have been verified for implementation in the ITk. We are in the stage of sensor pre-production with the first sensors already delivered in January of 2020.
A search for a WZ resonance, in the fully leptonic final state (electrons or muons), is performed using 139 fb Formula omitted of data collected at a centre-of-mass energy of 13 TeV by the ATLAS ...detector at the Large Hadron Collider. The results are interpreted in terms of a singly charged Higgs boson of the Georgi-Machacek model, produced by WZ fusion, and of a Heavy Vector Triplet, with the resonance produced by WZ fusion or the Drell-Yan process. No significant excess over the Standard Model prediction is observed and limits are set on the production cross-section times branching ratio as a function of the resonance mass for these processes.
A study of the charge conjugation and parity ( Formula omitted) properties of the interaction between the Higgs boson and Formula omitted-leptons is presented. The study is based on a measurement of ...Formula omitted-sensitive angular observables defined by the visible decay products of Formula omitted-leptons produced in Higgs boson decays. The analysis uses 139 fb Formula omitted of proton-proton collision data recorded at a centre-of-mass energy of Formula omitted TeV with the ATLAS detector at the Large Hadron Collider. Contributions from Formula omitted-violating interactions between the Higgs boson and Formula omitted-leptons are described by a single mixing angle parameter Formula omitted in the generalised Yukawa interaction. Without constraining the Formula omitted signal strength to its expected value under the Standard Model hypothesis, the mixing angle Formula omitted is measured to be Formula omitted, with an expected value of Formula omitted at the 68% confidence level. The pure Formula omitted-odd hypothesis is disfavoured at a level of 3.4 standard deviations. The results are compatible with the predictions for the Higgs boson in the Standard Model.
A search for supersymmetry involving the pair production of gluinos decaying via off-shell third-generation squarks into the lightest neutralino Formula omitted is reported. It exploits LHC ...proton-proton collision data at a centre-of-mass energy Formula omitted TeV with an integrated luminosity of 139 fb Formula omitted collected with the ATLAS detector from 2015 to 2018. The search uses events containing large missing transverse momentum, up to one electron or muon, and several energetic jets, at least three of which must be identified as containing b-hadrons. Both a simple kinematic event selection and an event selection based upon a deep neural-network are used. No significant excess above the predicted background is found. In simplified models involving the pair production of gluinos that decay via off-shell top (bottom) squarks, gluino masses less than 2.44 TeV (2.35 TeV) are excluded at 95% CL for a massless Formula omitted Limits are also set on the gluino mass in models with variable branching ratios for gluino decays to Formula omitted Formula omitted and Formula omitted
The exclusive production of pion pairs in the process Formula omitted has been measured at Formula omitted with the ATLAS detector at the LHC, using Formula omitted of low-luminosity data. The pion ...pairs were detected in the ATLAS central detector while outgoing protons were measured in the forward ATLAS ALFA detector system. This represents the first use of proton tagging to measure an exclusive hadronic final state at the LHC. A cross-section measurement is performed in two kinematic regions defined by the proton momenta, the pion rapidities and transverse momenta, and the pion-pion invariant mass. Cross-section values of Formula omitted and Formula omitted are obtained in the two regions; they are compared with theoretical models and provide a demonstration of the feasibility of measurements of this type.
A search for pair production of doubly charged Higgs bosons ( Formula omitted), each decaying into a pair of prompt, isolated, and highly energetic leptons with the same electric charge, is ...presented. The search uses a proton-proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb Formula omitted recorded by the ATLAS detector during Run 2 of the Large Hadron Collider (LHC). This analysis focuses on same-charge leptonic decays, Formula omitted where Formula omitted, in two-, three-, and four-lepton channels, but only considers final states which include electrons or muons. No evidence of a signal is observed. Corresponding upper limits on the production cross-section of a doubly charged Higgs boson are derived, as a function of its mass Formula omitted, at 95% confidence level. Assuming that the branching ratios to each of the possible leptonic final states are equal, Formula omitted, the observed (expected) lower limit on the mass of a doubly charged Higgs boson is 1080 GeV (1065 GeV) within the left-right symmetric type-II seesaw model, which is the strongest limit to date produced by the ATLAS Collaboration. Additionally, this paper provides the first direct test of the Zee-Babu neutrino mass model at the LHC, yielding an observed (expected) lower limit of Formula omitted = 900 GeV (880 GeV).
This paper reports a search for Higgs boson pair (hh) production in association with a vector boson ( Formula omitted) using 139 fb Formula omitted of proton-proton collision data at Formula omitted ...recorded with the ATLAS detector at the Large Hadron Collider. The search is performed in final states in which the vector boson decays leptonically ( Formula omitted with Formula omitted) and the Higgs bosons each decay into a pair of b-quarks. It targets Vhh signals from both non-resonant hh production, present in the Standard Model (SM), and resonant hh production, as predicted in some SM extensions. A 95% confidence-level upper limit of 183 (87) times the SM cross-section is observed (expected) for non-resonant Vhh production when assuming the kinematics are as expected in the SM. Constraints are also placed on Higgs boson coupling modifiers. For the resonant search, upper limits on the production cross-sections are derived for two specific models: one is the production of a vector boson along with a neutral heavy scalar resonance H, in the mass range 260-1000 GeV, that decays into hh, and the other is the production of a heavier neutral pseudoscalar resonance A that decays into a Z boson and H boson, where the A boson mass is 360-800 GeV and the H boson mass is 260-400 GeV. Constraints are also derived in the parameter space of two-Higgs-doublet models.
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