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Approximating significance scans of searches for new particles in high-energy physics experiments as Gaussian fields is a well-established way to estimate the trials factors required to quantify global significances. We propose a novel, highly efficient method to estimate the covariance matrix of such a Gaussian field. The method is based on the linear approximation of statistical fluctuations of the signal amplitude. For one-dimensional searches the upper bound on the trials factor can then be calculated directly from the covariance matrix. For higher dimensions, the Gaussian process described by this covariance matrix may be sampled to calculate the trials factor directly. This method also serves as the theoretical basis for a recent study of the trials factor with an empirically constructed set of Asmiov-like background datasets. We illustrate the method with studies of a \\(H \\rightarrow \\gamma \\gamma\\) inspired model that was used in the empirical paper.

In high-energy physics it is a recurring challenge to efficiently and precisely (enough) calculate the global significance of, e.g., a potential new resonance. We propose a new method that models the significance in the search region as a Gaussian Process. The kernel of the Gaussian Process is approximated with a covariance matrix and is calculated with a carefully designed set of background-only data sets, comparable in number to the random background-only data sets used in a typical analysis that relies on the average upcrossings of the significance. The trials factor for both low and moderate significances can subsequently be calculated to the desired precision with a computationally inexpensive random sampling of the Gaussian Process. In addition, once the covariance of the Gaussian Process is determined, the average number of upcrossings can be computed analytically. In our work we give some highlights of the analytic calculation and also discuss some peculiarities of the trials factor estimation on a finite grid. We illustrate the method with studies of three complementary statistical models.

For a Schrödinger operator on the plane R2 with electric potential V and an Aharonov–Bohm magnetic field, we obtain an upper bound on the number of its negative eigenvalues in terms of the L1(R2)-norm of V. Similar to Calogero’s bound in one dimension, the result is true under monotonicity assumptions on V. Our method of proof relies on a generalisation of Calogero’s bound to operator-valued potentials. We also establish a similar bound for the Schrödinger operator (without magnetic field) on the half-plane when a Dirichlet boundary condition is imposed and on the whole plane when restricted to antisymmetric functions.

A search is presented for the pair production of heavy vector-like B quarks, primarily targeting B quark decays into a W boson and a top quark. The search is based on 36.1 fb−1 of pp collisions at s=13 TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Data are analysed in the lepton-plus-jets final state, characterised by a high-transverse-momentum isolated electron or muon, large missing transverse momentum, and multiple jets, of which at least one is b-tagged. No significant deviation from the Standard Model expectation is observed. The 95% confidence level lower limit on the B mass is 1350 GeV assuming a 100% branching ratio to Wt. In the SU(2) singlet scenario, the lower mass limit is 1170 GeV. The 100% branching ratio limits are found to be also applicable to heavy vector-like X production, with charge +5/3, that decay into Wt. This search is also sensitive to a heavy vector-like B quark decaying into other final states (Zb and Hb) and thus mass limits on B production are set as a function of the decay branching ratios.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) A search is presented for a high-mass Higgs boson in the ..., ..., ..., and ... decay modes using the ATLAS detector at the CERN Large Hadron Collider. The search uses proton-proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb... The results of the search are interpreted in the scenario of a heavy Higgs boson with a width that is small compared with the experimental mass resolution. The Higgs boson mass range considered extends up to ... for all four decay modes and down to as low as 140 ..., depending on the decay mode. No significant excess of events over the Standard Model prediction is found. A simultaneous fit to the four decay modes yields upper limits on the production cross-section of a heavy Higgs boson times the branching ratio to ... boson pairs. 95 % confidence level upper limits range from 0.53 pb at ... GeV to 0.008 pb at ... GeV for the gluon-fusion production mode and from 0.31 pb at ... GeV to 0.009 pb at ... GeV for the vector-boson-fusion production mode. The results are also interpreted in the context of Type-I and Type-II two-Higgs-doublet models.

Cross-sections of associated production of a Higgs boson decaying into bottomquark pairs and an electroweak gauge boson, W or Z, decaying into leptons are measured as a function of the gauge boson transverse momentum. The measurements are performed in kinematic fiducial volumes defined in the ‘simplified template cross-section’ framework. The results are obtained using 79.8 fb−1 of proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. All measurements are found to be in agreement with the Standard Model predictions, and limits are set on the parameters of an effective Lagrangian sensitive to modifications of the Higgs boson couplings to the electroweak gauge bosons.

A significant amount of the computing resources available to the ATLAS experiment at the LHC are connected via the ARC grid middleware. ATLAS ARC-enabled resources, which consist of both major computing centers at the Tier-1 level and lesser, local clusters at Tier-2 and 3 level, have shown excellent performance running heavy Monte Carlo (MC) production for the experiment. However, with the imminent arrival of LHC physics data, it is imperative that the deployed grid middlewares also can handle data access patterns caused by user-defined physics analysis. These user-defined jobs can have radically different demands than systematic, centrally controlled MC production. We report on the performance of the ARC middleware, as deployed for ATLAS, for realistic situations with concurrent MC production and physics analysis running on the same resources. Data access patterns for ATLAS MC and physics analysis grid jobs will be shown, together with the performance of various possible storage and file staging models.

PurposeWest Nile Virus (WNV) is a mosquito-born RNA virus first recognized in Uganda in 1937. It has since emerged as an increasing threat across the United States. There have been 15,824 reported cases in the U.S. with 619 human deaths. Human disease manifestations range from a mild febrile illness to severe neurological disease with meningitis or encephalitis. Studies focusing on survivors of WNV have shown persistence of immunoglobulin M (IgM) against WNV. This study investigates whether or not the persistence of IgM can be explained by persistent viremia. Persistent viremia, if present, would have implications for increased blood and organ donation transmission and may explain persistent disease symptoms.MethodsPatients identified by the NM State Laboratory with acute WNV infection as demonstrated by positive IgM in serum or cerebrospinal fluid with persistent symptoms after acute infection were eligible for the study. Convalescent immunoglobulin levels were measured with Enzyme-Linked Immunoabsorbant Assay. Peripheral blood mononuclear cells (PBMCs) and serum were collected from eleven patients with persistent or equivocal IgM levels. RNA was extracted from PBMCs and serum. Reverse transcriptase polymerase chain reaction (RT-PCR) using specific WNV primers is presently underway. Agarose gel electrophoresis will be performed to evaluate RT-PCR product and viral sequencing will be performed for confirmation.ResultsOf the twenty-six WNV convalescent patients in the study, 23% remained IgM positive several months after initial diagnosis. An additional 19% of patients had equivocal IgM levels. All but two patients had persistence of IgG, one of which was equivocal.ConclusionNearly one-fourth of WNV patients with persistent symptoms months after acute infection have persistent IgM antibodies. RT-PCR presently underway will determine whether or not persistent viremia provides an explanation for persistent IgM levels. If RT-PCR indicates the presence of positive WNV RT-PCR products in PBMCs or serum of convalescent WNV patients, the natural history of the disease will be different than initially presumed, possibly increasing disease morbidity and increasing the transmission risk.

Abstract A search for a high-mass Higgs boson H is performed in the H [arrow right] WW [arrow right] νν and H [arrow right] WW [arrow right] νqq decay channels using pp collision data corresponding to an integrated luminosity of 20.3 fb-1 collected at ... TeV by the ATLAS detector at the Large Hadron Collider. No evidence of a high-mass Higgs boson is found. Limits on [sigma] H × BR(H [arrow right] WW) as a function of the Higgs boson mass m H are determined in three different scenarios: one in which the heavy Higgs boson has a narrow width compared to the experimental resolution, one for a width increasing with the boson mass and modeled by the complex-pole scheme following the same behavior as in the Standard Model, and one for intermediate widths. The upper range of the search is m H = 1500 GeV for the narrow-width scenario and m H = 1000 GeV for the other two scenarios. The lower edge of the search range is 200-300 GeV and depends on the analysis channel and search scenario. For each signal interpretation, individual and combined limits from the two WW decay channels are presented. At m H = 1500 GeV, the highest-mass point tested, [sigma] H × BR(H [arrow right] WW) for a narrow-width Higgs boson is constrained to be less than 22 fb and 6.6 fb at 95% CL for the gluon fusion and vector-boson fusion production modes, respectively. [Figure not available: see fulltext.]

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract Measurements of fiducial cross sections for the electroweak production of two jets in association with a Z-boson are presented. The measurements are performed using 20.3 fb^sup -1^ of proton-proton collision data collected at a centre-of-mass energy of ... = 8 TeV by the ATLAS experiment at the Large Hadron Collider. The electroweak component is extracted by a fit to the dijet invariant mass distribution in a fiducial region chosen to enhance the electroweak contribution over the dominant background in which the jets are produced via the strong interaction. The electroweak cross sections measured in two fiducial regions are in good agreement with the Standard Model expectations and the background-only hypothesis is rejected with significance above the 5[sigma] level. The electroweak process includes the vector boson fusion production of a Z-boson and the data are used to place limits on anomalous triple gauge boson couplings. In addition, measurements of cross sections and differential distributions for inclusive Z-boson-plus-dijet production are performed in five fiducial regions, each with different sensitivity to the electroweak contribution. The results are corrected for detector effects and compared to predictions from the Sherpa and Powheg event generators. [Figure not available: see fulltext.]