Showing papers by "David Cameron published in 2021"
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TL;DR: The results of this study define the genes that are most clinically useful for inclusion on panels for the prediction of breast cancer risk, as well as provide estimates of the risks associated with protein-truncating variants, to guide genetic counseling.
Abstract: BACKGROUND Genetic testing for breast cancer susceptibility is widely used, but for many genes, evidence of an association with breast cancer is weak, underlying risk estimates are imprecise, and reliable subtype-specific risk estimates are lacking. METHODS We used a panel of 34 putative susceptibility genes to perform sequencing on samples from 60,466 women with breast cancer and 53,461 controls. In separate analyses for protein-truncating variants and rare missense variants in these genes, we estimated odds ratios for breast cancer overall and tumor subtypes. We evaluated missense-variant associations according to domain and classification of pathogenicity. RESULTS Protein-truncating variants in 5 genes (ATM, BRCA1, BRCA2, CHEK2, and PALB2) were associated with a risk of breast cancer overall with a P value of less than 0.0001. Protein-truncating variants in 4 other genes (BARD1, RAD51C, RAD51D, and TP53) were associated with a risk of breast cancer overall with a P value of less than 0.05 and a Bayesian false-discovery probability of less than 0.05. For protein-truncating variants in 19 of the remaining 25 genes, the upper limit of the 95% confidence interval of the odds ratio for breast cancer overall was less than 2.0. For protein-truncating variants in ATM and CHEK2, odds ratios were higher for estrogen receptor (ER)-positive disease than for ER-negative disease; for protein-truncating variants in BARD1, BRCA1, BRCA2, PALB2, RAD51C, and RAD51D, odds ratios were higher for ER-negative disease than for ER-positive disease. Rare missense variants (in aggregate) in ATM, CHEK2, and TP53 were associated with a risk of breast cancer overall with a P value of less than 0.001. For BRCA1, BRCA2, and TP53, missense variants (in aggregate) that would be classified as pathogenic according to standard criteria were associated with a risk of breast cancer overall, with the risk being similar to that of protein-truncating variants. CONCLUSIONS The results of this study define the genes that are most clinically useful for inclusion on panels for the prediction of breast cancer risk, as well as provide estimates of the risks associated with protein-truncating variants, to guide genetic counseling.
407 citations
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TL;DR: In the phase III IMpassion130 trial, combining atezolizumab with first-line nanoparticle albumin-bound-paclitaxel for advanced triple-negative breast cancer (aTNBC) showed a statistically significant progression-free survival (PFS) benefit in the intention-to-treat (ITT) and programmed death-ligand 1 (PD-L1)-positive populations, and a clinically meaningful overall survival (OS) effect in PD-L 1-positive aTNBC as discussed by the authors.
285 citations
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TL;DR: In this article, the ATLAS particle-flow reconstruction method is used to reconstruct the topo-clusters of the proton-proton collision data with a center-of-mass energy of 13$ TeV collected by the LHC.
Abstract: Jet energy scale and resolution measurements with their associated uncertainties are reported for jets using 36-81 fb$^{-1}$ of proton-proton collision data with a centre-of-mass energy of $\sqrt{s}=13$ TeV collected by the ATLAS detector at the LHC. Jets are reconstructed using two different input types: topo-clusters formed from energy deposits in calorimeter cells, as well as an algorithmic combination of charged-particle tracks with those topo-clusters, referred to as the ATLAS particle-flow reconstruction method. The anti-$k_t$ jet algorithm with radius parameter $R=0.4$ is the primary jet definition used for both jet types. Jets are initially calibrated using a sequence of simulation-based corrections. Next, several $\textit{in situ}$ techniques are employed to correct for differences between data and simulation and to measure the resolution of jets. The systematic uncertainties in the jet energy scale for central jets ($|\eta| 2.5$ TeV). The relative jet energy resolution is measured and ranges from ($24 \pm 1.5$)% at 20 GeV to ($6 \pm 0.5$)% at 300 GeV.
131 citations
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TL;DR: In this paper, the authors investigated the long-term benefits and risks of adjuvant trastuzumab on breast cancer recurrence and cause-specific mortality, and did a collaborative meta-analysis of individual patient data from randomised trials.
Abstract: Summary Background Trastuzumab targets the extracellular domain of the HER2 protein. Adding trastuzumab to chemotherapy for patients with early-stage, HER2-positive breast cancer reduces the risk of recurrence and death, but is associated with cardiac toxicity. We investigated the long-term benefits and risks of adjuvant trastuzumab on breast cancer recurrence and cause-specific mortality. Methods We did a collaborative meta-analysis of individual patient data from randomised trials assessing chemotherapy plus trastuzumab versus the same chemotherapy alone. Randomised trials that enrolled women with node-negative or node-positive, operable breast cancer were included. We collected individual patient-level data on baseline characteristics, dates and sites of first distant breast cancer recurrence and any previous local recurrence or second primary cancer, and the date and underlying cause of death. Primary outcomes were breast cancer recurrence, breast cancer mortality, death without recurrence, and all-cause mortality. Standard intention-to-treat log-rank analyses, stratified by age, nodal status, oestrogen receptor (ER) status, and trial yielded first-event rate ratios (RRs). Findings Seven randomised trials met the inclusion criteria, and included 13 864 patients enrolled between February, 2000, and December, 2005. Mean scheduled treatment duration was 14·4 months and median follow-up was 10·7 years (IQR 9·5 to 11·9). The risks of breast cancer recurrence (RR 0·66, 95% CI 0·62 to 0·71; p Interpretation Adding trastuzumab to chemotherapy for early-stage, HER2-positive breast cancer reduces recurrence of, and mortality from, breast cancer by a third, with worthwhile proportional reductions irrespective of recorded patient and tumour characteristics. Funding Cancer Research UK, UK Medical Research Council.
108 citations
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TL;DR: In this article, a search for the dimuon decay of the Standard Model (SM) Higgs boson is performed using data corresponding to an integrated luminosity of 139 −fb−1 collected with the ATLAS detector in Run 2 pp collisions at s = 13 TeV at the Large Hadron Collider.
92 citations
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TL;DR: In this paper, the authors describe the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139.5 million collision data collected between 2015 and 2018 during Run 2 of the LHC, and show that the improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution.
Abstract: This article documents the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139 $$\hbox {fb}^{-1}$$
fb
-
1
of pp collision data at $$\sqrt{s}=13$$
s
=
13
TeV collected between 2015 and 2018 during Run 2 of the LHC. The increased instantaneous luminosity delivered by the LHC over this period required a reoptimisation of the criteria for the identification of prompt muons. Improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution. The availability of large samples of $$Z\rightarrow \mu \mu $$
Z
→
μ
μ
and $$J/\psi \rightarrow \mu \mu $$
J
/
ψ
→
μ
μ
decays, and the minimisation of systematic uncertainties, allows the efficiencies of criteria for muon identification, primary vertex association, and isolation to be measured with an accuracy at the per-mille level in the bulk of the phase space, and up to the percent level in complex kinematic configurations. Excellent performance is achieved over a range of transverse momenta from 3 GeV to several hundred GeV, and across the full muon detector acceptance of $$|\eta |<2.7$$
|
η
|
<
2.7
.
86 citations
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TL;DR: In this paper, the Higgs boson properties in the four-lepton decay channel (where lepton = e, mu) were studied using 139 fb(-1) of proton-proton collision data recorded at v s =13 TeV by the ATLAS experiment at the Lar...
Abstract: Higgs boson properties are studied in the fourlepton decay channel (where lepton = e, mu) using 139 fb(-1) of proton-proton collision data recorded at v s =13 TeV by the ATLAS experiment at the Lar ...
59 citations
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58 citations
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Université libre de Bruxelles1, Hebron University2, Breast International Group3, Sheba Medical Center4, Memorial Sloan Kettering Cancer Center5, University of Milan6, Institute of Cancer Research7, Medical University of Graz8, Champalimaud Foundation9, Pompeu Fabra University10, Centre Hospitalier de Luxembourg11, European Organisation for Research and Treatment of Cancer12, Katholieke Universiteit Leuven13, Edinburgh Cancer Research Centre14, Sahlgrenska University Hospital15, Paracelsus Private Medical University of Salzburg16, University of Genoa17, Fred Hutchinson Cancer Research Center18, Princess Margaret Cancer Centre19, Peter MacCallum Cancer Centre20, Wellcome Trust Sanger Institute21
TL;DR: AURORA as discussed by the authors aims to study the processes of relapse in metastatic breast cancer (MBC) by performing multi-omics profiling on paired primary tumors and early-course metastases.
Abstract: AURORA aims to study the processes of relapse in metastatic breast cancer (MBC) by performing multi-omics profiling on paired primary tumors and early-course metastases. Among 381 patients (primary tumor and metastasis pairs: 252 targeted gene sequencing, 152 RNA sequencing, 67 single nucleotide polymorphism arrays), we found a driver role for GATA1 and MEN1 somatic mutations. Metastases were enriched in ESR1, PTEN, CDH1, PIK3CA, and RB1 mutations; MDM4 and MYC amplifications; and ARID1A deletions. An increase in clonality was observed in driver genes such as ERBB2 and RB1. Intrinsic subtype switching occurred in 36% of cases. Luminal A/B to HER2-enriched switching was associated with TP53 and/or PIK3CA mutations. Metastases had lower immune score and increased immune-permissive cells. High tumor mutational burden correlated to shorter time to relapse in HR+/HER2− cancers. ESCAT tier I/II alterations were detected in 51% of patients and matched therapy was used in 7%. Integration of multi-omics analyses in clinical practice could affect treatment strategies in MBC. Significance: The AURORA program, through the genomic and transcriptomic analyses of matched primary and metastatic samples from 381 patients with breast cancer, coupled with prospectively collected clinical data, identified genomic alterations enriched in metastases and prognostic biomarkers. ESCAT tier I/II alterations were detected in more than half of the patients. This article is highlighted in the In This Issue feature, p. 2659
53 citations
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TL;DR: In this paper, a search for charged Higgs bosons decaying into W±W± or W±Z bosons is performed, involving experimental signatures with two leptons of the same charge, or three or four lepton with a variety of charge combinations, missing transverse momentum and jets.
Abstract: A search for charged Higgs bosons decaying into W±W± or W±Z bosons is performed, involving experimental signatures with two leptons of the same charge, or three or four leptons with a variety of charge combinations, missing transverse momentum and jets. A data sample of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018 is used. The data correspond to a total integrated luminosity of 139 fb−1. The search is guided by a type-II seesaw model that extends the scalar sector of the Standard Model with a scalar triplet, leading to a phenomenology that includes doubly and singly charged Higgs bosons. Two scenarios are explored, corresponding to the pair production of doubly charged H±± bosons, or the associated production of a doubly charged H±± boson and a singly charged H± boson. No significant deviations from the Standard Model predictions are observed. H±± bosons are excluded at 95% confidence level up to 350 GeV and 230 GeV for the pair and associated production modes, respectively. [Figure not available: see fulltext.]
49 citations
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TL;DR: In this article, a search for supersymmetric partners of quarks and gluons (squarks, gluinos) in final states containing jets and missing transverse momentum, but no electrons or muons, is presented.
Abstract: A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded by the ATLAS experiment in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb$^{-1}$. The results are interpreted in the context of various $R$-parity-conserving models where squarks and gluinos are produced in pairs or in association and a neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.30 TeV for a simplified model containing only a gluino and the lightest neutralino, assuming the latter is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.85 TeV are excluded if the lightest neutralino is massless. These limits extend substantially beyond the region of supersymmetric parameter space excluded previously by similar searches with the ATLAS detector.
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TL;DR: In this article, a measurement of light-by-light scattering based on Pb+Pb collision data recorded by the ATLAS experiment during Run 2 of the LHC is described.
Abstract: This paper describes a measurement of light-by-light scattering based on Pb+Pb collision data recorded by the ATLAS experiment during Run 2 of the LHC. The study uses 2.2 nb$^{−1}$ of integrated luminosity collected in 2015 and 2018 at $ \sqrt{s_{\mathrm{NN}}} $ = 5.02 TeV. Light-by-light scattering candidates are selected in events with two photons produced exclusively, each with transverse energy $ {E}_{\mathrm{T}}^{\gamma } $> 2.5 GeV, pseudorapidity |η$_{γ}$| 5 GeV, and with small diphoton transverse momentum and diphoton acoplanarity. The integrated and differential fiducial cross sections are measured and compared with theoretical predictions. The diphoton invariant mass distribution is used to set limits on the production of axion-like particles. This result provides the most stringent limits to date on axion-like particle production for masses in the range 6–100 GeV. Cross sections above 2 to 70 nb are excluded at the 95% CL in that mass interval.[graphic not available: see fulltext]
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TL;DR: In this article, the associated production of a Higgs boson decaying into b quark pairs with a W or Z gauge boson, decaying into leptons, are measured in two exclusive vector boson transverse momentum regions, 250-400 GeV and above 400 GeV, and interpreted as constraints on anomalous couplings in the framework of a Standard Model effective field theory.
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Harvard University1, American Society of Clinical Oncology2, Ohio State University3, Memorial Sloan Kettering Cancer Center4, Food and Drug Administration5, Duke University6, Institute of Cancer Research7, Sunnybrook Health Sciences Centre8, University of North Carolina at Chapel Hill9, Beth Israel Deaconess Medical Center10, University of Colorado Denver11, Edinburgh Cancer Research Centre12, National Institutes of Health13
TL;DR: The Standardized Definitions for Efficacy End Points (STEEP) criteria, established in 2007, provide standardized definitions of adjuvant breast cancer clinical trial end points as discussed by the authors.
Abstract: PURPOSEThe Standardized Definitions for Efficacy End Points (STEEP) criteria, established in 2007, provide standardized definitions of adjuvant breast cancer clinical trial end points. Given the ev...
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TL;DR: In this paper, a search for heavy resonances decaying into a pair of Z bosons leading to either an electron or a muon is presented, where the results are interpreted as upper limits on the production cross section of a spin-0 or spin-2 resonance.
Abstract: A search for heavy resonances decaying into a pair of Z bosons leading to $\ell ^+\ell ^-\ell '^+\ell '^-$ and $\ell ^+\ell ^-
u {{\bar{
u }}}$ final states, where $\ell $ stands for either an electron or a muon, is presented. The search uses proton–proton collision data at a centre-of-mass energy of 13 TeV collected from 2015 to 2018 that corresponds to the integrated luminosity of 139 $\mathrm {fb}^{-1}$ recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. Different mass ranges spanning 200 GeV to 2000 GeV for the hypothetical resonances are considered, depending on the final state and model. In the absence of a significant observed excess, the results are interpreted as upper limits on the production cross section of a spin-0 or spin-2 resonance. The upper limits for the spin-0 resonance are translated to exclusion contours in the context of Type-I and Type-II two-Higgs-doublet models, and the limits for the spin-2 resonance are used to constrain the Randall–Sundrum model with an extra dimension giving rise to spin-2 graviton excitations.
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TL;DR: The effects of cancer treatment on reproductive function in both sexes may lead to loss of fertility, sexual desire and function, and hormone deficiency, which results in additional long-term morbidity in more than a third of patients as mentioned in this paper.
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TL;DR: In this article, a search for pair production of third-generation scalar leptoquarks decaying into a top quark and a τ-lepton is presented based on a dataset of pp collisions at s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1.
Abstract: A search for pair production of third-generation scalar leptoquarks decaying into a top quark and a τ-lepton is presented The search is based on a dataset of pp collisions at s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1 Events are selected if they have one light lepton (electron or muon) and at least one hadronically decaying τ -lepton, or at least two light leptons In addition, two or more jets, at least one of which must be identified as containing b-hadrons, are required Six final states, defined by the multiplicity and flavour of lepton candidates, are considered in the analysis Each of them is split into multiple event categories to simultaneously search for the signal and constrain several leading backgrounds The signal-rich event categories require at least one hadronically decaying τ-lepton candidate and exploit the presence of energetic final-state objects, which is characteristic of signal events No significant excess above the Standard Model expectation is observed in any of the considered event categories, and 95% CL upper limits are set on the production cross section as a function of the leptoquark mass, for different assumptions about the branching fractions into tτ and bν Scalar leptoquarks decaying exclusively into tτ are excluded up to masses of 143 TeV while, for a branching fraction of 50% into tτ, the lower mass limit is 122 TeV [Figure not available: see fulltext]
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TL;DR: In this article, an adversarial neural network was used to detect the decay of the Higgs Boson to b-quark pairs in the vector boson fusion (VBF) production mode, and the signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, was measured to be 0.95-0.36+0.38.
Abstract: The paper presents a measurement of the Standard Model Higgs Boson decaying to b-quark pairs in the vector boson fusion (VBF) production mode. A sample corresponding to 126 fb - 1 of s=13TeV proton–proton collision data, collected with the ATLAS experiment at the Large Hadron Collider, is analyzed utilizing an adversarial neural network for event classification. The signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, is measured to be 0.95-0.36+0.38 , corresponding to an observed (expected) significance of 2.6 (2.8) standard deviations from the background only hypothesis. The results are additionally combined with an analysis of Higgs bosons decaying to b-quarks, produced via VBF in association with a photon.
07 Jun 2021
TL;DR: In this paper, a search for chargino-$neutralino pair production in three-lepton final states with missing transverse momentum was presented, based on a dataset of 13$ TeV $pp$ collisions recorded with the ATLAS detector at the LHC.
Abstract: A search for chargino$-$neutralino pair production in three-lepton final states with missing transverse momentum is presented. The study is based on a dataset of $\sqrt{s} = 13$ TeV $pp$ collisions recorded with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 139 fb$^{-1}$. No significant excess relative to the Standard Model predictions is found in data. The results are interpreted in simplified models of supersymmetry, and statistically combined with results from a previous ATLAS search for compressed spectra in two-lepton final states. Various scenarios for the production and decay of charginos ($\tilde\chi^\pm_1$) and neutralinos ($\tilde\chi^0_2$) are considered. For pure higgsino $\tilde\chi^\pm_1\tilde\chi^0_2$ pair-production scenarios, exclusion limits at 95% confidence level are set on $\tilde\chi^0_2$ masses up to 210 GeV. Limits are also set for pure wino $\tilde\chi^\pm_1\tilde\chi^0_2$ pair production, on $\tilde\chi^0_2$ masses up to 640 GeV for decays via on-shell $W$ and $Z$ bosons, up to 300 GeV for decays via off-shell $W$ and $Z$ bosons, and up to 190 GeV for decays via $W$ and Standard Model Higgs bosons.
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TL;DR: The 10 year follow data from the PRIME 2 trial shows that the omission of RT after BCS in women aged ≥ 65 years with T1-2, pN0 hormone receptor positive breast cancer results in only 9.8% IBTR, which suggests that postoperative radiotherapy in this patient group who are receiving adjuvant hormonal therapy does not impact on overall survival.
Abstract: Background: There is limited level 1 evidence on the long term outcomes after loco-regional radiotherapy after breast conserving surgery (BCS) in older patients when they are also receiving appropriate systemic therapy. Practice and guidelines vary. PRIME 2 is an international phase 3 RCT designed to address this specific question. Methods: From April 2003 to December 2009, 1326 patients were randomised to receive (n=658) or not receive (n=668) whole breast radiotherapy (RT). Eligible patients were aged ≥ 65 years, T1-2 (up to 3cm) NO, MO, hormone receptor positive, clear excision margins (minimum 1mm), axillary node negative (pNO) receiving adjuvant hormonal therapy. Patients were eligible if they had grade 3 tumours or lymphovascular invasion but not both. The target accrual was 1300 patients based on detecting a difference in local recurrence rates between 5% in the no RT arm and 2% in the RT arm at 5 years, with 80% power and 5% significance. Ipsilateral breast tumour recurrence (IBTR) was the primary endpoint. Secondary endpoints were regional recurrence, contralateral breast cancer, distant metastases and overall survival. Results: Median follow up is 7.3 years. At 10 years IBTR was 9.8% (95% CI 6.5, 13.2%) in the no RT arm and 0.9% (95% CI 0.1, 1.6%) in the RT arm. The hazard ratio for IBTR for those receiving RT was 0.12 (95% CI 0.05, 0.31)(p Conclusions: 10 year follow data from the PRIME 2 trial shows that the omission of RT after BCS in women aged ≥ 65 years with T1-2, pN0 hormone receptor positive breast cancer results in only 9.8% IBTR. While this rate is significantly reduced by RT (to 0.9%), the absolute reduction is modest, and there were no differences in the secondary endpoints of distant metastases, contralateral breast cancer or overall survival and a small but significant difference in regional recurrence. These data suggest that postoperative radiotherapy in this patient group who are receiving adjuvant hormonal therapy does not impact on overall survival in the context of modern approaches to local and systemic adjuvant therapy, with most patients in both arms dying of causes unrelated to breast cancer or its treatment. Citation Format: Ian H Kunkler, Linda J Williams, Wilma Jack, David A Cameron, Michael Dixon. Prime 2 randomised trial (postoperative radiotherapy in minimum-risk elderly): Wide local excision and adjuvant hormonal therapy +/- whole breast irradiation in women =/> 65 years with early invasive breast cancer: 10 year results [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS2-03.
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TL;DR: This search provides unique sensitivity to long-lived scalar supersymmetric lepton partners (sleptons) for lifetimes of 0.1 ns, drastically improving on the previous best limits from LEP.
Abstract: A search for charged leptons with large impact parameters using 139 fb^{-1} of sqrt[s]=13 TeV pp collision data from the ATLAS detector at the LHC is presented, addressing a long-standing gap in coverage of possible new physics signatures. Results are consistent with the background prediction. This search provides unique sensitivity to long-lived scalar supersymmetric lepton partners (sleptons). For lifetimes of 0.1 ns, selectron, smuon, and stau masses up to 720, 680, and 340 GeV, respectively, are excluded at 95% confidence level, drastically improving on the previous best limits from LEP.
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TL;DR: In this article, a search for new phenomena with top quark pairs in final states with one isolated electron or muon, multiple jets, and large missing transverse momentum is performed.
Abstract: A search for new phenomena with top quark pairs in final states with one isolated electron or muon, multiple jets, and large missing transverse momentum is performed. Signal regions are designed to search for two-, three-, and four-body decays of the directly pair-produced supersymmetric partner of the top quark (stop). Additional signal regions are designed specifically to search for spin-0 mediators that are produced in association with a pair of top quarks and decay into a pair of dark-matter particles. The search is performed using the Large Hadron Collider proton-proton collision dataset at a centre-of-mass energy of s = 13 TeV recorded by the ATLAS detector from 2015 to 2018, corresponding to an integrated luminosity of 139 fb−1. No significant excess above the Standard Model background is observed, and limits at 95% confidence level are set in the stop-neutralino mass plane and as a function of the mediator mass or the dark-matter particle mass. Stops are excluded up to 1200 GeV (710 GeV) in the two-body (three-body) decay scenario. In the four-body scenario stops up to 640 GeV are excluded for a stop-neutralino mass difference of 60 GeV. Scalar and pseudoscalar dark-matter mediators are excluded up to 200 GeV when the coupling strengths of the mediator to Standard Model and dark-matter particles are both equal to one and when the mass of the dark-matter particle is 1 GeV. [Figure not available: see fulltext.] © 2021, The Author(s).
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TL;DR: In this paper, a search for the pair production of heavy leptons as predicted by the type-III seesaw mechanism is presented, using proton-proton collision data at a centre-of-mass energy of 13TeV, corresponding to 139fb-1 of integrated luminosity recorded by the ATLAS detector during Run 2 of the Large Hadron Collider.
Abstract: A search for the pair production of heavy leptons as predicted by the type-III seesaw mechanism is presented. The search uses proton–proton collision data at a centre-of-mass energy of 13 TeV, corresponding to 139fb-1 of integrated luminosity recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. The analysis focuses on the final state with two light leptons (electrons or muons) of different flavour and charge combinations, with at least two jets and large missing transverse momentum. No significant excess over the Standard Model expectation is observed. The results are translated into exclusion limits on heavy-lepton masses, and the observed lower limit on the mass of the type-III seesaw heavy leptons is 790 GeV at 95% confidence level. © 2021, CERN for the benefit of the ATLAS collaboration.
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TL;DR: In this paper, measurements of four-lepton differential and integrated fiducial cross-sections in events with two same-flavour, opposite-charge electron or muon pairs are presented.
Abstract: Measurements of four-lepton differential and integrated fiducial cross-sections in events with two same-flavour, opposite-charge electron or muon pairs are presented. The data correspond to 139 fb−1 of s = 13 TeV proton-proton collisions, collected by the ATLAS detector during Run 2 of the Large Hadron Collider (2015–2018). The final state has contributions from a number of interesting Standard Model processes that dominate in different four-lepton invariant mass regions, including single Z boson production, Higgs boson production and on-shell ZZ production, with a complex mix of interference terms, and possible contributions from physics beyond the Standard Model. The differential cross-sections include the four-lepton invariant mass inclusively, in slices of other kinematic variables, and in different lepton flavour categories. Also measured are dilepton invariant masses, transverse momenta, and angular correlation variables, in four regions of four-lepton invariant mass, each dominated by different processes. The measurements are corrected for detector effects and are compared with state-of-the-art Standard Model calculations, which are found to be consistent with the data. The Z → 4l branching fraction is extracted, giving a value of (4.41 ± 0.30) × 10−6. Constraints on effective field theory parameters and a model based on a spontaneously broken B − L gauge symmetry are also evaluated. Further reinterpretations can be performed with the provided information. [Figure not available: see fulltext.]
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TL;DR: In this paper, a search for dark matter is conducted in final states containing a photon and missing transverse momentum in proton-proton collisions at the CERN LHC, and 95% confidence-level upper limits between 2.45 fb and 0.5 fb are set on the visible cross section for contributions from physics beyond the Standard Model, in different ranges of the missing transversal momentum.
Abstract: A search for dark matter is conducted in final states containing a photon and missing transverse momentum in proton-proton collisions at $$ \sqrt{s} $$
= 13 TeV. The data, collected during 2015–2018 by the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139 fb−1. No deviations from the predictions of the Standard Model are observed and 95% confidence-level upper limits between 2.45 fb and 0.5 fb are set on the visible cross section for contributions from physics beyond the Standard Model, in different ranges of the missing transverse momentum. The results are interpreted as 95% confidence-level limits in models where weakly interacting dark-matter candidates are pair-produced via an s-channel axial-vector or vector mediator. Dark-matter candidates with masses up to 415 (580) GeV are excluded for axial-vector (vector) mediators, while the maximum excluded mass of the mediator is 1460 (1470) GeV. In addition, the results are expressed in terms of 95% confidence-level limits on the parameters of a model with an axion-like particle produced in association with a photon, and are used to constrain the coupling gaZγ of an axion-like particle to the electroweak gauge bosons.
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TL;DR: In this paper, a search for pair production of scalar leptoquarks, each decaying into either an electron or a muon and a top quark, is presented.
Abstract: A search for pair production of scalar leptoquarks, each decaying into either an electron or a muon and a top quark, is presented. This is the first leptoquark search using ATLAS data to investigate top-philic cross-generational couplings that could provide explanations for recently observed anomalies in B meson decays. This analysis targets high leptoquark masses which cause the decay products of each resultant top quark to be contained within a single high-pT large-radius jet. The full Run 2 dataset is exploited, consisting of 139fb-1 of data collected from proton–proton collisions at s=13TeV from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. In the absence of any significant deviation from the background expectation, lower limits on the leptoquark masses are set at 1480GeV and 1470GeV for the electron and muon channel, respectively.
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TL;DR: Real-time national SACT delivery data from NHS Scotland shows an initial rapid reduction in patient attendance for SACT with a subsequent rapid and full recovery following service re-design, which reflected a co-ordinated national approach and associated patient and clinician support structures.
Abstract: Understanding the impact of the COVID-19 pandemic on systemic anticancer therapy delivery (SACT) is crucial to appreciate the short- and long-term consequences for cancer patients and plan future care. Here, we report real-time national SACT delivery data from NHS Scotland. We demonstrate an initial rapid reduction in patient attendance of 28.7% with subsequent rapid recovery following service redesign. The smallest decrease was seen in breast cancer (19.7%), which also had the most rapid recovery and the largest decrease seen in colorectal cancer (43.4%). Regional variation in the magnitude of impact on SACT delivery was observed, but nadirs occurred at the same time and the rate of recovery was similar across all regions. This recovery reflected a coordinated national approach and associated patient and clinician support structures, which facilitated the creation of COVID-19-protected areas for SACT delivery in Scottish cancer centres enabling rapid sharing of successful and innovative strategies. The data show that these actions have limited the disadvantage to cancer patients.
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TL;DR: A measurement of the Bs0→J/ψϕ decay parameters using 80.5fb-1 of integrated luminosity collected with the ATLAS detector from 13-Te proton-proton collisions at the LHC is presented in this paper.
Abstract: A measurement of the Bs0→J/ψϕ decay parameters using 80.5fb-1 of integrated luminosity collected with the ATLAS detector from 13 Te proton–proton collisions at the LHC is presented. The measured parameters include the CP-violating phase ϕs, the width difference Δ Γ s between the Bs0 meson mass eigenstates and the average decay width Γ s. The values measured for the physical parameters are combined with those from 19.2fb-1 of 7 and 8 Te data, leading to the following: ϕs=-0.087±0.036(stat.)±0.021(syst.)radΔΓs=0.0657±0.0043(stat.)±0.0037(syst.)ps-1Γs=0.6703±0.0014(stat.)±0.0018(syst.)ps-1Results for ϕs and Δ Γ s are also presented as 68% confidence level contours in the ϕs–Δ Γ s plane. Furthermore the transversity amplitudes and corresponding strong phases are measured. ϕs and Δ Γ s measurements are in agreement with the Standard Model predictions. © 2021, The Author(s).
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TL;DR: In this article, the photon-induced production of W-boson pairs, gamma gamma → WW, was observed using 139 fb(-1) of LHC proton-proton collision data taken at root s = 13 TeV re
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TL;DR: In this paper, the first measurement of longitudinal decorrelations of harmonic flow amplitudes for n=2-4 in Xe+Xe collisions at the LHC was obtained using 3'0μb^{-1} of data with the ATLAS detector.
Abstract: The first measurement of longitudinal decorrelations of harmonic flow amplitudes v_{n} for n=2-4 in Xe+Xe collisions at sqrt[s_{NN}]=5.44 TeV is obtained using 3 μb^{-1} of data with the ATLAS detector at the LHC. The decorrelation signal for v_{3} and v_{4} is found to be nearly independent of collision centrality and transverse momentum (p_{T}) requirements on final-state particles, but for v_{2} a strong centrality and p_{T} dependence is seen. When compared with the results from Pb+Pb collisions at sqrt[s_{NN}]=5.02 TeV, the longitudinal decorrelation signal in midcentral Xe+Xe collisions is found to be larger for v_{2}, but smaller for v_{3}. Current hydrodynamic models reproduce the ratios of the v_{n} measured in Xe+Xe collisions to those in Pb+Pb collisions but fail to describe the magnitudes and trends of the ratios of longitudinal flow decorrelations between Xe+Xe and Pb+Pb. The results on the system-size dependence provide new insights and an important lever arm to separate effects of the longitudinal structure of the initial state from other early and late time effects in heavy-ion collisions.