Publications by authors named "Cameron Khan"

This Letter presents a search for highly ionizing magnetic monopoles in 262  μb^{-1} of ultraperipheral Pb+Pb collision data at sqrt[s_{NN}]=5.36  TeV collected by the ATLAS detector at the LHC. A new methodology that exploits the properties of clusters of hits reconstructed in the innermost silicon detector layers is introduced to study highly ionizing particles in heavy-ion data.

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Z boson events at the Large Hadron Collider can be selected with high purity and are sensitive to a diverse range of QCD phenomena. As a result, these events are often used to probe the nature of the strong force, improve Monte Carlo event generators, and search for deviations from standard model predictions. All previous measurements of Z boson production characterize the event properties using a small number of observables and present the results as differential cross sections in predetermined bins.

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Background: Suboptimal cardiovascular health (CVH) in pregnancy is associated with adverse maternal and offspring outcomes. To guide public health efforts to reduce disparities in maternal CVH, we determined the contribution of individual- and neighborhood-level factors to racial and ethnic differences in early pregnancy CVH.

Methods: We included nulliparous individuals with singleton pregnancies who self-identified as Hispanic, non-Hispanic Black (NHB), or non-Hispanic White (NHW) and participated in the nuMoM2b cohort study (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be).

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High-energy nuclear collisions create a quark-gluon plasma, whose initial condition and subsequent expansion vary from event to event, impacting the distribution of the eventwise average transverse momentum [P([p_{T}])]. Disentangling the contributions from fluctuations in the nuclear overlap size (geometrical component) and other sources at a fixed size (intrinsic component) remains a challenge. This problem is addressed by measuring the mean, variance, and skewness of P([p_{T}]) in ^{208}Pb+^{208}Pb and ^{129}Xe+^{129}Xe collisions at sqrt[s_{NN}]=5.

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We examined the association between blood pressure (BP) in the early third trimester and hypertension 10-14 years after delivery per American College of Cardiology and American Heart Association recommendations. We conducted a secondary analysis using the prospective HAPO FUS (Hyperglycemia and Adverse Pregnancy Outcome Follow-up Study) in patients without a chronic hypertension diagnosis. The exposure and outcome were systolic and diastolic BP measured in the early third trimester and 10-14 years after delivery, respectively.

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Importance: Population mean levels of total cholesterol and fasting triglycerides have decreased substantially in the US in recent decades, but improvements in cardiometabolic health may have slowed among younger cohorts. Conversely, prevalence of diabetes (types 1 and 2) and obesity has increased, especially among adults younger than 65 years. It is unclear how trends in cholesterol, triglyceride, and glucose levels have changed across different birth cohorts and whether adverse trends in obesity are associated with these patterns.

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Article Synopsis
  • * A cross-sectional survey conducted from August 2019 to April 2021 involved 1,477 adults over 18, with findings showing 37.1% experienced UI weekly, highlighting variations in UI types among countries—Cameron reported the highest at 40%, while Brazil had the lowest at 15%.
  • * Common symptoms identified included urinary urgency (59.9%) and nocturia (50.6%), with men reporting voiding issues more often, while women experienced
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Background And Aims: Per-oral endoscopic myotomy (POEM) is an established treatment for achalasia. We aim to review outcomes of all POEM cases performed in New Zealand for achalasia.

Methods: A retrospective review of all POEM procedures performed in the five hospitals offering POEM between November 2015 and December 2022 was undertaken.

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A search for the exclusive hadronic decays W^{±}→π^{±}γ, W^{±}→K^{±}γ, and W^{±}→ρ^{±}γ is performed using up to 140  fb^{-1} of proton-proton collisions recorded with the ATLAS detector at a center-of-mass energy of sqrt[s]=13  TeV. If observed, these rare processes would provide a unique test bench for the quantum chromodynamics factorization formalism used to calculate cross sections at colliders. Additionally, at future colliders, these decays could offer a new way to measure the W boson mass through fully reconstructed decay products.

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Article Synopsis
  • - The ATLAS experiment at the LHC conducted a search for long-lived particles (LLPs) using a large dataset (140 fb^{-1}) from proton-proton collisions at 13 TeV, focusing on LLPs with masses from 5 to 55 GeV that decay within the inner detector.
  • - The study considered scenarios where LLPs are produced from exotic Higgs boson decays and models involving axionlike particles (ALPs).
  • - No significant findings above expected background levels were detected, leading to the establishment of upper limits on various production rates involving the Higgs boson and the top quark related to LLPs and ALPs.
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  • The study investigates the associated production of Higgs and W bosons, focusing on how the relative signs of the Higgs couplings to W and Z bosons impact the process.
  • Two specific searches were conducted using large amounts of collision data from the LHC to analyze different coupling scenarios: one for opposite-sign couplings and another for same-sign (standard model-like) couplings.
  • The results significantly exclude the opposite-sign coupling hypothesis and set a strict upper limit on the production rate of this process compared to standard model predictions.
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This Letter presents results from a combination of searches for Higgs boson pair production using 126-140  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV recorded with the ATLAS detector. At 95% confidence level (CL), the upper limit on the production rate is 2.9 times the standard model (SM) prediction, with an expected limit of 2.

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This Letter presents the first study of the energy dependence of diboson polarization fractions in WZ→ℓνℓ^{'}ℓ^{'}(ℓ,ℓ^{'}=e,μ) production. The dataset used corresponds to an integrated luminosity of 140  fb^{-1} of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector. Two fiducial regions with an enhanced presence of events featuring two longitudinally polarized bosons are defined.

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Statistical combinations of searches for charginos and neutralinos using various decay channels are performed using 139  fb^{-1} of pp collision data at sqrt[s]=13  TeV with the ATLAS detector at the Large Hadron Collider. Searches targeting pure-wino chargino pair production, pure-wino chargino-neutralino production, or Higgsino production decaying via standard model W, Z, or h bosons are combined to extend the mass reach to the produced supersymmetric particles by 30-100 GeV. The depth of the sensitivity of the original searches is also improved by the combinations, lowering the 95% C.

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Article Synopsis
  • * The measurements utilized both semileptonic and hadronic decays of top quarks, along with events focused on single top quark production in the electroweak t channel.
  • * The combined result for the top quark mass is 172.52 GeV, with a reduced total uncertainty of 0.33 GeV, showcasing an improvement of 31% over previous measurements.
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Objective: To evaluate the relationship between changes in Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) enrollment during pregnancy from 2016 to 2019 and rates of adverse pregnancy outcomes in U.S. counties in 2019.

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A combination of searches for a new resonance decaying into a Higgs boson pair is presented, using up to 139  fb^{-1} of pp collision data at sqrt[s]=13  TeV recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: bb[over ¯]bb[over ¯], bb[over ¯]τ^{+}τ^{-}, and bb[over ¯]γγ. No excess above the expected Standard Model background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV-5 TeV.

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Higgsinos with masses near the electroweak scale can solve the hierarchy problem and provide a dark matter candidate, while detecting them at the LHC remains challenging if their mass splitting is O(1  GeV). This Letter presents a novel search for nearly mass-degenerate Higgsinos in events with an energetic jet, missing transverse momentum, and a low-momentum track with a significant transverse impact parameter using 140  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV collected by the ATLAS experiment. For the first time since LEP, a range of mass splittings between the lightest charged and neutral Higgsinos from 0.

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Angular correlations between heavy quarks provide a unique probe of the quark-gluon plasma created in ultrarelativistic heavy-ion collisions. Results are presented of a measurement of the azimuthal angle correlations between muons originating from semileptonic decays of heavy quarks produced in 5.02 TeV Pb+Pb and pp collisions at the LHC.

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While obesity is associated with an increased risk of venous thromboembolism (VTE), there is some data to suggest that higher BMI is also associated with decreased all-cause mortality in patients with a pulmonary embolism (PE). Using PE Response Team (PERT) activation data from a large tertiary hospital between 27 October 2020 and 28 August 2023, we constructed a multivariate Cox proportional hazards model to assess the association between obesity as a dichotomous variable (defined as BMI ≥ 30 vs. BMI 18.

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This Letter presents the first study of Higgs boson production in association with a vector boson (V=W or Z) in the fully hadronic qqbb final state using data recorded by the ATLAS detector at the LHC in proton-proton collisions at sqrt[s]=13  TeV and corresponding to an integrated luminosity of 137  fb^{-1}. The vector bosons and Higgs bosons are each reconstructed as large-radius jets and tagged using jet substructure techniques. Dedicated tagging algorithms exploiting b-tagging properties are used to identify jets consistent with Higgs bosons decaying into bb[over ¯].

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ATLAS measured the centrality dependence of the dijet yield using 165  nb^{-1} of p+Pb data collected at sqrt[s_{NN}]=8.16  TeV in 2016. The event centrality, which reflects the p+Pb impact parameter, is characterized by the total transverse energy registered in the Pb-going side of the forward calorimeter.

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