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1.	Blokland, G. A. M., et al. (författare) Sex-Dependent Shared and Nonshared Genetic Architecture Across Mood and Psychotic Disorders 2022 Ingår i: Biological Psychiatry. - : Elsevier BV. - 0006-3223 .- 1873-2402. ; 91:1, s. 102-117 Tidskriftsartikel (refereegranskat)abstract Background: Sex differences in incidence and/or presentation of schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BIP) are pervasive. Previous evidence for shared genetic risk and sex differences in brain abnormalities across disorders suggest possible shared sex-dependent genetic risk. Methods: We conducted the largest to date genome-wide genotype-by-sex (G×S) interaction of risk for these disorders using 85,735 cases (33,403 SCZ, 19,924 BIP, and 32,408 MDD) and 109,946 controls from the PGC (Psychiatric Genomics Consortium) and iPSYCH. Results: Across disorders, genome-wide significant single nucleotide polymorphism–by-sex interaction was detected for a locus encompassing NKAIN2 (rs117780815, p = 3.2 × 10−8), which interacts with sodium/potassium-transporting ATPase (adenosine triphosphatase) enzymes, implicating neuronal excitability. Three additional loci showed evidence (p < 1 × 10−6) for cross-disorder G×S interaction (rs7302529, p = 1.6 × 10−7; rs73033497, p = 8.8 × 10−7; rs7914279, p = 6.4 × 10−7), implicating various functions. Gene-based analyses identified G×S interaction across disorders (p = 8.97 × 10−7) with transcriptional inhibitor SLTM. Most significant in SCZ was a MOCOS gene locus (rs11665282, p = 1.5 × 10−7), implicating vascular endothelial cells. Secondary analysis of the PGC-SCZ dataset detected an interaction (rs13265509, p = 1.1 × 10−7) in a locus containing IDO2, a kynurenine pathway enzyme with immunoregulatory functions implicated in SCZ, BIP, and MDD. Pathway enrichment analysis detected significant G×S interaction of genes regulating vascular endothelial growth factor receptor signaling in MDD (false discovery rate-corrected p < .05). Conclusions: In the largest genome-wide G×S analysis of mood and psychotic disorders to date, there was substantial genetic overlap between the sexes. However, significant sex-dependent effects were enriched for genes related to neuronal development and immune and vascular functions across and within SCZ, BIP, and MDD at the variant, gene, and pathway levels. © 2021 Society of Biological Psychiatry
2.	Aaron, F. D., et al. (författare) A general search for new phenomena at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 674:4-5, s. 257-268 Tidskriftsartikel (refereegranskat)abstract A model-independent search for deviations from the Standard Model prediction is performed using the full e(+/-) p data sample collected by the H1 experiment at HERA. All event topologies involving isolated electrons, photons, muons, neutrinos and jets with transverse momenta above 20 GeV are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A dedicated algorithm is used to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or the invariant mass of final state particles and to quantify their significance. Variables related to angular distributions and energy sharing between final state particles are also introduced to study the final state topologies. No significant deviation from the Standard Model expectation is observed in the phase space covered by this analysis. (C) 2009 Elsevier B.V. All rights reserved.
3.	Aaron, F. D., et al. (författare) A search for excited neutrinos in e(-) p collisions at HERA 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 663:5, s. 382-389 Tidskriftsartikel (refereegranskat)abstract A search for first generation excited neutrinos is performed using the full e(-) p data sample collected by the HI experiment at HERA at a centre-of-mass energy of 319 GeV, corresponding to a total luminosity of 184 pb(-1). The electroweak decays of excited neutrinos nu* -> nu gamma, v* -> nu Z and nu* -> eW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for excited neutrino production is found. Mass dependent exclusion limits on nu* production cross sections and on the ratio of the coupling to the compositeness scale f/boolean AND are derived within gauge mediated models. A limit on f/boolean AND A, independent of the relative couplings to the SU(2) and U(1) gauge bosons, is also determined. These limits extend the excluded region to higher masses than has been possible in previous excited neutrino searches. (c) 2008 Elsevier B.V. All rights reserved.
4.	Abolfathi, Bela, et al. (författare) The Fourteenth Data Release of the Sloan Digital Sky Survey : First Spectroscopic Data from the Extended Baryon Oscillation Spectroscopic Survey and from the Second Phase of the Apache Point Observatory Galactic Evolution Experiment 2018 Ingår i: Astrophysical Journal Supplement Series. - : IOP Publishing Ltd. - 0067-0049 .- 1538-4365. ; 235:2 Tidskriftsartikel (refereegranskat)abstract The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.
5.	Attié, David, et al. (författare) A time projection chamber with GEM-based readout 2017 Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 856, s. 109-118 Tidskriftsartikel (refereegranskat)abstract For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1. T solenoidal field and read out with three independent Gas Electron Multiplier (GEM) based readout modules, are reported. The TPC was exposed to a 6. GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.
6.	Blanton, Michael R., et al. (författare) Sloan Digital Sky Survey IV : Mapping the Milky Way, Nearby Galaxies, and the Distant Universe 2017 Ingår i: Astronomical Journal. - : IOP Publishing Ltd. - 0004-6256 .- 1538-3881. ; 154:1 Tidskriftsartikel (refereegranskat)abstract We describe the Sloan Digital Sky Survey IV (SDSS-IV), a project encompassing three major spectroscopic programs. The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is observing hundreds of thousands of Milky Way stars at high resolution and. high signal-to-noise ratios in the near-infrared. The Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey is obtaining spatially resolved spectroscopy for thousands of nearby galaxies (median z similar to 0.03). The extended Baryon Oscillation Spectroscopic Survey (eBOSS) is mapping the galaxy, quasar, and neutral gas distributions between z similar to 0.6 and 3.5 to constrain cosmology using baryon acoustic oscillations, redshift space distortions, and the shape of the power spectrum. Within eBOSS, we are conducting two major subprograms: the SPectroscopic IDentification of eROSITA Sources (SPIDERS), investigating X-ray AGNs. and galaxies in X-ray clusters, and the Time Domain Spectroscopic Survey (TDSS), obtaining spectra of variable sources. All programs use the 2.5 m Sloan Foundation Telescope at the. Apache Point Observatory; observations there began in Summer 2014. APOGEE-2 also operates a second near-infrared spectrograph at the 2.5 m du Pont Telescope at Las Campanas Observatory, with observations beginning in early 2017. Observations at both facilities are scheduled to continue through 2020. In keeping with previous SDSS policy, SDSS-IV provides regularly scheduled public data releases; the first one, Data Release 13, was made available in 2016 July.
7.	Ghalwash, Mohamed, et al. (författare) Islet autoantibody screening in at-risk adolescents to predict type 1 diabetes until young adulthood : a prospective cohort study 2023 Ingår i: The Lancet Child and Adolescent Health. - 2352-4642. ; 7:4, s. 261-268 Tidskriftsartikel (refereegranskat)abstract Background: Screening for islet autoantibodies in children and adolescents identifies individuals who will later develop type 1 diabetes, allowing patient and family education to prevent diabetic ketoacidosis at onset and to enable consideration of preventive therapies. We aimed to assess whether islet autoantibody screening is effective for predicting type 1 diabetes in adolescents aged 10−18 years with an increased risk of developing type 1 diabetes. Methods: Data were harmonised from prospective studies from Finland (the Diabetes Prediction and Prevention study), Germany (the BABYDIAB study), and the USA (Diabetes Autoimmunity Study in the Young and the Diabetes Evaluation in Washington study). Autoantibodies against insulin, glutamic acid decarboxylase, and insulinoma-associated protein 2 were measured at each follow-up visit. Children who were lost to follow-up or diagnosed with type 1 diabetes before 10 years of age were excluded. Inverse probability censoring weighting was used to include data from remaining participants. Sensitivity and the positive predictive value of these autoantibodies, tested at one or two ages, to predict type 1 diabetes by the age of 18 years were the main outcomes. Findings: Of 20 303 children with an increased type 1 diabetes risk, 8682 were included for the analysis with inverse probability censoring weighting. 1890 were followed up to 18 years of age or developed type 1 diabetes between the ages of 10 years and 18 years, and their median follow-up was 18·3 years (IQR 14·5–20·3). 442 (23·4%) of 1890 adolescents were positive for at least one islet autoantibody, and 262 (13·9%) developed type 1 diabetes. Time from seroconversion to diabetes diagnosis increased by 0·64 years (95% CI 0·34–0·95) for each 1-year increment of diagnosis age (Pearson's correlation coefficient 0·88, 95% CI 0·50–0·97, p=0·0020). The median interval between the last prediagnostic sample and diagnosis was 0·3 years (IQR 0·1–1·3) in the 227 participants who were autoantibody positive and 6·8 years (1·6–9·9) for the 35 who were autoantibody negative. Single screening at the age of 10 years was 90% (95% CI 86–95) sensitive, with a positive predictive value of 66% (60–72) for clinical diabetes. Screening at two ages (10 years and 14 years) increased sensitivity to 93% (95% CI 89–97) but lowered the positive predictive value to 55% (49–60). Interpretation: Screening of adolescents at risk for type 1 diabetes only once at 10 years of age for islet autoantibodies was highly effective to detect type 1 diabetes by the age of 18 years, which in turn could enable prevention of diabetic ketoacidosis and participation in secondary prevention trials. Funding: JDRF International.
8.	Grumer, Jon, et al. (författare) Magnetic field induced transition rates in Ne- and Be-like ions for plasma diagnostics and E1M1 two-photon decay rate determination 2014 Ingår i: XXVIII International Conference on Photonic, Electronic and Atomic Collisions (ICPEAC 2013). - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 488, s. 152005-152005 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract We report on theoretical results of magnetic field induced transitions (MITs) in Ne- and Be-like ions without nuclear spin for two applicalions. Firstly, MITs are promising candidates in the determination of magnetic fields in plasmas. In our work on Ne-like ions we present accurate theoretical MIT rates for 2p(6 1)S(O) - 2p(5)3s 3P(O),2 [11. Purthermore, for Be-like ions, it has been proposed to extract the rate of the BIM1 two-photon transition 2s(2 1)S(O) - 2s2p P-3(O) by measuring the lifetime of the 'Po state using a storage ring, which involves an external magnetic field. The MIT rates are carefully evaluated and shown to be of the same order as the ElMI rates [2].
9.	Grumer, Jon, et al. (författare) Magnetic ﬁeld induced transition rates in Ne- and Be-like ions for plasma diagnostics and E1M1 two-photon decay rate determination 2013 Ingår i: Book of abstracts. - : Institute of Modern Physics, Chinese Academy of Sciences. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Synopsis We report on theoretical results of magnetic field induced transitions (MITs) in Ne- and Be-like ions without nuclear spin for two applications. Firstly, MITs are promising candidates in the determination of magnetic fields in plasmas. In our work on Ne-like ions we present accurate theoretical MIT rates for 2p6 1S0 − 2p53s 3P0 , 2 [1]. Furthermore, for Be-like ions, it has been proposed to extract the rate of the E1M1 two-photon transition 2s2 1S0 − 2s2p 3P0 by measuring the lifetime of the 3P0 state using a storage ring, which involves an external magnetic field. The MIT rates are carefully evaluated and shown to be of the same order as the E1M1 rates.
10.	Grumer, Jon, et al. (författare) The effect of an external magnetic field on the determination of E1M1 two-photon decay rates in Be-like ions 2013 Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 88 Tidskriftsartikel (refereegranskat)abstract In this work we report on ab initio theoretical results for the magnetic-field-induced 2s 2p 3P0 → 2s2 1S0 E1 transition for ions in the beryllium isoelectronic sequence between Z = 5 and 92. It has been proposed that the rate of the E1M1 two-photon transition 2s 2p 3P0 → 2s2 1S0 can be extracted from the lifetime of the 3P0 state in Be-like ions with zero nuclear spin by employing resonant recombination in a storage ring. This experimental approach involves a perturbing external magnetic field. The effect of this field needs to be evaluated in order to properly extract the two-photon rate from the measured decay curves. The magnetic-field-induced transition rates are carefully evaluated, and it is shown that, with a typical storage-ring field strength, it is dominant or of the same order as the E1M1 rate for low- and mid-Z ions. Results for several field strengths and ions are presented, and we also give a simple Z-dependent formula for the rate. We estimate the uncertainties of our model to be within 5% for low- and mid-Z ions and slightly larger for more highly charged ions. Furthermore we evaluate the importance of including both perturber states, 3P1 and 1P1, and it is s
11.	Grumer, Jon, et al. (författare) Unexpected transitions induced by spin-dependent, hyperfine and external magnetic-field interactions 2014 Ingår i: Physica Scripta. - : IOP Publishing. - 0031-8949 .- 1402-4896. ; 89:11 Tidskriftsartikel (refereegranskat)abstract Unexpected transitions are induced by weaker interactions not included in the gross structure model of the ion under investigation. We discuss different examples of such decay channels, starting with relativistic spin-induced transitions. These represented an important field of study a few decades ago, and we illustrate how some challenging cases can be treated very accurately with today's computational techniques, while close degeneracy sometimes still prevents ab initio methods from obtaining accurate results. For hyperfine induced transitions we review some recent results and discuss remaining challenges for experiment and theory. Finally, we discuss the newly opened field of accurate calculations for transitions induced by an external magnetic field and point to some examples of where these are accessible for experimental tests.
12.	Jiguang, Li, et al. (författare) Forbidden and Unexpected Transitions in Atomic Ions 2013 Konferensbidrag (övrigt vetenskapligt/konstnärligt)
13.	Jönsson, Per, et al. (författare) An Introduction to Relativistic Theory as Implemented in GRASP 2023 Ingår i: Atoms. - : MDPI. - 2218-2004. ; 11:1 Tidskriftsartikel (refereegranskat)abstract Computational atomic physics continues to play a crucial role in both increasing the understanding of fundamental physics (e.g., quantum electrodynamics and correlation) and producing atomic data for interpreting observations from large-scale research facilities ranging from fusion reactors to high-power laser systems, space-based telescopes and isotope separators. A number of different computational methods, each with their own strengths and weaknesses, is available to meet these tasks. Here, we review the relativistic multiconfiguration method as it applies to the General Relativistic Atomic Structure Package [grasp2018, C. Froese Fischer, G. Gaigalas, P. Jonsson, J. Bieron, Comput. Phys. Commun. (2018). DOI: 10.1016/j.cpc.2018.10.032]. To illustrate the capacity of the package, examples of calculations of relevance for nuclear physics and astrophysics are presented.
14.	Jönsson, Per, et al. (författare) GRASP Manual for Users 2023 Ingår i: Atoms. - : MDPI. - 2218-2004. ; 11:4 Tidskriftsartikel (refereegranskat)abstract grasp is a software package in Fortran 95, adapted to run in parallel under MPI, for research in atomic physics. The basic premise is that, given a wave function, any observed atomic property can be computed. Thus, the first step is always to determine a wave function. Different properties challenge the accuracy of the wave function in different ways. This software is distributed under the MIT Licence.
15.	Li, Jiguang, et al. (författare) Theoretical investigation of magnetic-field-induced 2p53s 3P0 - 2p6 1S0 transitions in Ne-like ions without nuclear spin 2013 Ingår i: Physical Review A. Atomic, Molecular, and Optical Physics. - : American Physical Society. - 1050-2947 .- 1094-1622. ; 88:1 Tidskriftsartikel (refereegranskat)abstract We report theoretical results for magnetic-field-induced 2p53s 3P0,2 − 2p6 1S0 E1 transitions in Ne-like ions with zero nuclear spin (I = 0) between Mg III and Zn XXI as well as in Ne I.We demonstrate that it is important to include both “perturber” states 2p53s 1P1 and 2p53s 3P1 in order to produce reliable transition rates. Furthermore, we investigate the trends of the rates along the isoelectronic sequence of the 2p53s 3P0,2 − 2p6 1S0 transitions and their competition with the 2p53s 3P0 − 2p53s 3P1 M1 and the 2p53s 3P2 − 2p6 1S0 M2 decays. For the 2p53s 3P0 state the magnetic-field-induced transition becomes the dominant decay channel for the light elements even in a relatively weak magnetic field, and it will therefore prove useful in diagnostics of the strength of magnetic fields in different plasmas. The influence of an external magnetic field on the lifetime of the 2p53s 3P2 state is much smaller but still observable for the ions near the neutral end of the sequence. As a special case, the magnetic field effect on the lifetimes of 2p53s 3P0,2 states of neutral 20Ne is discussed. It is found that the lifetimes are drastically reduced by a magnetic field, which may be an underlying reason for the discrepancies in the lifetime of the 2p53s 3P2 state between experiment [14.73(14) s] and theory (17.63 s).
16.	Li, M. C., et al. (författare) Extended MCDHF Calculations of Energy Levels and Transition Data for N I 2023 Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics Publishing (IOPP). - 0067-0049 .- 1538-4365. ; 265:1 Tidskriftsartikel (refereegranskat)abstract Accurate and extensive atomic data are essential for spectroscopic analyses of stellar atmospheres and other astronomical objects. We present energy levels, lifetimes, and transition probabilities for neutral nitrogen, the sixth most abundant element in the cosmos. The calculations employ the fully relativistic multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction methods, and span the 103 lowest states up to and including 2s(2)2p(2)5s. Our theoretical energies are in excellent agreement with the experimental data, with an average relative difference of 0.07%. In addition, our transition probabilities are in good agreement with available experimental and theoretical data. We further verify the agreement of our data with experimental results via a reanalysis of the solar nitrogen abundance, with the results from the Babushkin and Coulomb gauges consistent to 2% or 0.01 dex. We estimated the uncertainties of the computed transition data based on a statistical analysis of the differences between the transition rates in the Babushkin and Coulomb gauges. Out of the 1701 computed electric dipole transitions in this work, 83 (536) are associated with uncertainties smaller than 5% (10%).
17.	Li, W., et al. (författare) Extended atomic data for oxygen abundance analyses 2023 Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 674 Tidskriftsartikel (refereegranskat)abstract As the most abundant element in the universe after hydrogen and helium, oxygen plays a key role in planetary, stellar, and galactic astrophysics. Its abundance is especially influential in terms of stellar structure and evolution, and as the dominant opacity contributor at the base of the Sun's convection zone, it is central to the discussion on the solar modelling problem. However, abundance analyses require complete and reliable sets of atomic data. We present extensive atomic data for O I by using the multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction methods. We provide the lifetimes and transition probabilities for radiative electric dipole transitions and we compare them with results from previous calculations and available measurements. The accuracy of the computed transition rates is evaluated by the differences between the transition rates in Babushkin and Coulomb gauges, as well as via a cancellation factor analysis. Out of the 989 computed transitions in this work, 205 are assigned to the accuracy classes AA-B, that is, with uncertainties smaller than 10%, following the criteria defined by the Atomic Spectra Database from the National Institute of Standards and Technology. We discuss the influence of the new log(gf) values on the solar oxygen abundance, ultimately advocating for log epsilon(O) = 8.70 +/- 0.04.
18.	Li, Yanting, et al. (författare) Fine-Tuning of Atomic Energies in Relativistic Multiconfiguration Calculations 2023 Ingår i: Atoms. - : MDPI. - 2218-2004. ; 11:4 Tidskriftsartikel (refereegranskat)abstract Ab initio calculations sometimes do not reproduce the experimentally observed energy separations at a high enough accuracy. Fine-tuning of diagonal elements of the Hamiltonian matrix is a process which seeks to ensure that calculated energy separations of the states that mix are in agreement with experiment. The process gives more accurate measures of the mixing than can be obtained in ab initio calculations. Fine-tuning requires the Hamiltonian matrix to be diagonally dominant, which is generally not the case for calculations based on jj-coupled configuration state functions. We show that this problem can be circumvented by a method that transforms the Hamiltonian in jj-coupling to a Hamiltonian in LSJ-coupling for which fine-tuning applies. The fine-tuned matrix is then transformed back to a Hamiltonian in jj-coupling. The implementation of the method into the General Relativistic Atomic Structure Package is described and test runs to validate the program operations are reported. The new method is applied to the computation of the 2s(21)S(0)-2s2p(1,3)P(1) transitions in C III and to the computation of Rydberg transitions in B I, for which the 2s(2)p(22)S(1/2) perturber enters the 2s(2)ns(2)S(1/2) series. Improved convergence patterns and results are found compared with ab initio calculations.
19.	Li, Yang, et al. (författare) Multiconfiguration Dirac-Hartree-Fock calculations of energy levels and radiative rates of Fe VII 2018 Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press. - 0035-8711 .- 1365-2966. ; 479:1, s. 1260-1266 Tidskriftsartikel (refereegranskat)abstract Detailed calculations arc performed for 134 fine-structure levels of the 3p(6)3d(2), 3p(6)3d4s, 3p(5)3d(3) and 3p(6)3d4p configurations in Fe ViT using the multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) methods. Important electron correlation effects are systematically accounted for through active space (AS) expansions. Our results compare well with experimental measurements, emphasizing the importance of a careful treatment of electron correlation, and provide some missing data in the NIST atomic database. The data obtained are expected to be useful in astrophysical applications, particularly for the research of the solar coronal plasma.
20.	Li, Yanting, et al. (författare) Performance Tests and Improvements on the rmcdhf and rci Programs of GRASP 2023 Ingår i: Atoms. - : MDPI. - 2218-2004. ; 11:1 Tidskriftsartikel (refereegranskat)abstract The latest published version of GRASP (General-purpose Relativistic Atomic Structure Package), i.e., GRASP2018, retains a few suboptimal subroutines/algorithms, which reflect the limited memory and file storage of computers available in the 1980s. Here we show how the efficiency of the relativistic self-consistent-field (SCF) procedure of the multiconfiguration-Dirac-Hartree-Fock (MCDHF) method and the relativistic configuration-interaction (RCI) calculations can be improved significantly. Compared with the original GRASP codes, the present modified version reduces the CPU times by factors of a few tens or more. The MPI performances for all the original and modified codes are carefully analyzed. Except for diagonalization, all computational processes show good MPI scaling.
21.	Liu, Jing-fu, et al. (författare) Disposable ionic liquid coating for headspace solid-phase microextraction of benzene, toluene, ethylbenzene. and xylenes in paints followed by gas chromatography-flame ionization detection 2005 Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673. ; 1066:1-2, s. 27-32 Tidskriftsartikel (refereegranskat)abstract Solid-phase microextraction (SPME) with a disposable ionic liquid (IL) coating was developed for headspace extraction of benzene, toluene, ethylbenzene, and xylenes (BTEX) in paints. The SPME fiber was coated with IL prior to every extraction, then the analytes were extracted and desorbed on the injection port of gas chromatography, and finally the IL coating on the fiber was washed out with solvents. The coating and washing out of IL from the fiber can be finished in a few minutes. This disposable IL-coated fiber was applied to determine BTEX in water-soluble paints with results in good agreement with that obtained by using commercially available SPME fibers. For all the four studied paints samples, the benzene contents were under the detection limits, but relatively high contents of toluene, ethylbenzene and xylenes (56-271 mug g(-1)) were detected with spiked recoveries in the range of 70-114%. Compared to the widely used commercially available SPME fibers, this proposed disposable IL-coated fiber has much lower cost per determination, comparable reproducibility (RSD < 11%), and no carryover between each determination. Considering that IL possess good extractability for various organic compounds and metals ions, and that task-specific IL can be designed and synthesized for selective extraction of target analytes, this disposable IL coating SPME might has great potential in sample preparation. (C) 2005 Elsevier B.V. All rights reserved.
22.	Ma, Mingxuan, et al. (författare) Natural Orbitals and Targeted Non-Orthogonal Orbital Sets for Atomic Hyperfine Structure Multiconfiguration Calculations 2024 Ingår i: Atoms. - : MDPI. - 2218-2004. ; 12:6 Tidskriftsartikel (refereegranskat)abstract Hyperfine structure constants have many applications, but are often hard to calculate accurately due to large and canceling contributions from different terms of the hyperfine interaction operator, and also from different closed and spherically symmetric core subshells that break up due to electron correlation effects. In multiconfiguration calculations, the wave functions are expanded in terms of configuration state functions (CSFs) built from sets of one-electron orbitals. The orbital sets are typically enlarged within the layer-by-layer approach. The calculations are energy-driven, and orbitals in each new layer of correlation orbitals are spatially localized in regions where the weighted total energy decreases the most, overlapping and breaking up different closed core subshells in an irregular pattern. As a result, hyperfine structure constants, computed as expectation values of the hyperfine operators, often show irregular or oscillating convergence patterns. Large orbital sets, and associated large CSF expansions, are needed to obtain converged values of the hyperfine structure constants. We analyze the situation for the states of the {2s22p3,2s22p23p,2s22p24p} odd and {2s22p23s,2s2p4,2s22p24s,2s22p23d} even configurations in N I, and show that the convergence with respect to the increasing sets of orbitals is radically improved by introducing separately optimized orbital sets targeted for describing the spin- and orbital-polarization effects of the 1s and 2s core subshells that are merged with, and orthogonalized against, the ordinary energy-optimized orbitals. In the layer-by-layer approach, the spectroscopic orbitals are kept frozen from the initial calculation and are not allowed to relax in response to the introduced layers of correlation orbitals. To compensate for this lack of variational freedom, the orbitals are transformed to natural orbitals prior to the final calculation based on single and double substitutions from an increased multireference set. The use of natural orbitals has an important impact on the states of the 2s22p23s configuration, bringing the corresponding hyperfine interaction constants in closer agreement with experiment. Relying on recent progress in methodology, the multiconfiguration calculations are based on configuration state function generators, cutting down the time for spin-angular integration by factors of up to 50, compared to ordinary calculations.
23.	Satizabal, Claudia L., et al. (författare) Genetic architecture of subcortical brain structures in 38,851 individuals 2019 Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 51:11, s. 1624- Tidskriftsartikel (refereegranskat)abstract Subcortical brain structures are integral to motion, consciousness, emotions and learning. We identified common genetic variation related to the volumes of the nucleus accumbens, amygdala, brainstem, caudate nucleus, globus pallidus, putamen and thalamus, using genome-wide association analyses in almost 40,000 individuals from CHARGE, ENIGMA and UK Biobank. We show that variability in subcortical volumes is heritable, and identify 48 significantly associated loci (40 novel at the time of analysis). Annotation of these loci by utilizing gene expression, methylation and neuropathological data identified 199 genes putatively implicated in neurodevelopment, synaptic signaling, axonal transport, apoptosis, inflammation/infection and susceptibility to neurological disorders. This set of genes is significantly enriched for Drosophila orthologs associated with neurodevelopmental phenotypes, suggesting evolutionarily conserved mechanisms. Our findings uncover novel biology and potential drug targets underlying brain development and disease.
24.	The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data 2022 Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2 Tidskriftsartikel (refereegranskat)abstract This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
25.	Wang, Kai, et al. (författare) Calculations with spectroscopic accuracy : Energies and transition rates in the nitrogen isoelectronic sequence from Ar XII to Zn XXIV 2016 Ingår i: Astrophysical Journal Supplement Series. - : American Astronomical Society. - 0067-0049 .- 1538-4365. ; 223:1 Tidskriftsartikel (refereegranskat)abstract Combined relativistic configuration interaction and many-body perturbation calculations are performed for the 359 fine-structure levels of the 2s2 2p3, 2 s2p4, 2p5, 2s2 2p2 3l, 2 s2p3 3l, 2p4 3l, and 2s2 2p2 4l configurations in N-like ions from Ar XII to Zn XXIV. Complete and consistent data sets of energies, wavelengths, radiative rates, oscillator strengths, and line strengths for all possible electric dipole, magnetic dipole, electric quadrupole, and magnetic quadrupole transitions among the 359 levels are given for each ion. The present work significantly increases the amount of accurate data for ions in the nitrogen-like sequence, and the accuracy of the energy levels is high enough to enable the identification and interpretation of observed spectra involving the n=3, 4 levels, for which experimental values are largely scarce. Meanwhile, the results should be of great help for modeling and diagnosing astrophysical and fusion plasmas.
26.	Aaron, F. D., et al. (författare) A precision measurement of the inclusive ep scattering cross section at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 64:4, s. 561-587 Tidskriftsartikel (refereegranskat)abstract A measurement of the inclusive deep inelastic neutral current e(+) p scattering cross section is reported in the region of four-momentum transfer squared, 12GeV(2) <= Q(2) <= 150 GeV2, and Bjorken x, 2 x 10(-4) <= x <= 0.1. The results are based on data collected by the H1 Collaboration at the ep collider HERA at positron and proton beam energies of E-e = 27.6 GeV and E-p = 920 GeV, respectively. The data are combined with previously published data, taken at E-p = 820 GeV. The accuracy of the combined measurement is typically in the range of 1.3-2%. A QCD analysis at next-to-leading order is performed to determine the parton distributions in the proton based on H1 data.
27.	Aaron, F. D., et al. (författare) Combined measurement and QCD analysis of the inclusive e(+/-)p scattering cross sections at HERA 2010 Ingår i: Journal of High Energy Physics. - 1029-8479. ; :1 Tidskriftsartikel (refereegranskat)abstract A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e(+/-)p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q(2), and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions, HERAPDF1.0, with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
28.	Aaron, F. D., et al. (författare) Deeply virtual Compton scattering and its beam charge asymmetry in e(+/-)p collisions at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 681:5, s. 391-399 Tidskriftsartikel (refereegranskat)abstract A measurement of elastic deeply virtual Compton scattering gammap --> gamma p using e(+) p and e(-) p collision data recorded with the HI detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 306 pb(-1), almost equally shared between both beam charges. The cross section is measured as a function of the virtuality Q(2) of the exchanged photon and the centre-of-mass energy W of the gammap system in the kinematic domain 6.5 < Q(2) < 80 GeV2, 30 < W < 140 GeV and \|t\| < 1 GeV2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q(2) and W values and exponential t-slope parameters are derived. Using e(+) p and e(-) p data samples, a beam charge asymmetry is extracted for the first time in the low Biorken x kinematic domain. The observed asymmetry is attributed to the interference between Bethe-Heitler and deeply virtual Compton scattering processes. Experimental results are discussed in the context of two different models, one based on generalised parton distributions and one based on the dipole approach. (C) 2009 Elsevier B.V. All rights reserved.
29.	Aaron, F. D., et al. (författare) Diffractive electroproduction of rho and phi mesons at HERA 2010 Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2010:5, s. 1-111 Tidskriftsartikel (refereegranskat)abstract Diffractive electroproduction of rho and phi mesons is measured at HERA with the H1 detector in the elastic and proton dissociative channels. The data correspond to an integrated luminosity of 51 pb(-1). About 10500 rho and 2000 phi events are analysed in the kinematic range of squared photon virtuality 2.5 <= Q(2) <= 60 GeV2, photon-proton centre of mass energy 35 <= W <= 180 GeV and squared four-momentum transfer to the proton vertical bar t vertical bar <= 3 GeV2. The total, longitudinal and transverse cross sections are measured as a function of Q(2), W and vertical bar t vertical bar. The measurements show a transition to a dominantly "hard" behaviour, typical of high gluon densities and small q (q) over bar dipoles, for Q(2) larger than 10 to 20 GeV2. They support flavour independence of the diffractive exchange, expressed in terms of the scaling variable (Q(2) + M-V(2))/4, and proton vertex factorisation. The spin density matrix elements are measured as a function of kinematic variables. The ratio of the longitudinal to transverse cross sections, the ratio of the helicity amplitudes and their relative phases are extracted. Several of these measurements have not been performed before and bring new information on the dynamics of diffraction in a QCD framework. The measurements are discussed in the context of models using generalised parton distributions or universal dipole cross sections.
30.	Aaron, F. D., et al. (författare) Events with an isolated lepton and missing transverse momentum and measurement of W production at HERA 2010 Ingår i: Journal of High Energy Physics. - 1029-8479. ; 2010:3, s. 1-19 Tidskriftsartikel (refereegranskat)abstract A search for events containing an isolated electron or muon and missing trans verse momentum produced in e(+/-)p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994-2007 and correspond to an integrated luminosity of 0.98 fb(-1). The observed event yields are in good overall agreement with the Standard Model prediction, which is dominated by single W production. In the e(+)p data, at large hadronic transverse momentum P-T(X) > 25GeV, a total of 23 events are observed compared to a prediction of 14.0 +/- 1.9. The total single W boson production cross section is measured as 1.06 +/- 0.16 (stat.) +/- 0.07 (sys.) pb, in agreement with an Standard Model (SM) expectation of 1.26 +/- 0.19 pb.
31.	Aaron, F. D., et al. (författare) Events with isolated leptons and missing transverse momentum and measurement of W production at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 64:2, s. 251-271 Tidskriftsartikel (refereegranskat)abstract Events with high energy isolated electrons, muons or tau leptons and missing transverse momentum are studied using the full e(+/-)p data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb(-1). Within the Standard Model, events with isolated leptons and missing transverse momentum mainly originate from the production of single W bosons. The total single W boson production cross section is measured as 1.14 +/- 0.25 (stat.) +/- 0.14 (sys.) pb, in agreement with the Standard Model expectation. The data are also used to establish limits on the WW gamma gauge couplings and for a measurement of the W boson polarisation.
32.	Aaron, F. D., et al. (författare) Inclusive deep inelastic scattering at high Q(2) with longitudinally polarised lepton beams at HERA 2012 Ingår i: Journal of High Energy Physics. - 1029-8479. ; :9 Tidskriftsartikel (refereegranskat)abstract Inclusive e(+/-)p single and double differential cross sections for neutral and charged current deep inelastic scattering processes are measured with the H1 detector at HERA. The data were taken at a centre-of-mass energy of root s = 319 GeV with a total integrated luminosity of 333.7 pb(-1) shared between two lepton beam charges and two longitudinal lepton polarisation modes. The differential cross sections are measured in the range of negative four-momentum transfer squared, Q(2), between 60 and 50 000GeV(2), and Bjorken x between 0.0008 and 0.65. The measurements are combined with earlier published unpolarised H1 data to improve statistical precision and used to determine the structure function xF(3)(gamma Z). A measurement of the neutral current parity violating structure function F-2(gamma Z) is presented for the first time. The polarisation dependence of the charged current total cross section is also measured. The new measurements are well described by a next-to-leading order QCD fit based on all published H1 inclusive cross section data which are used to extract the parton distribution functions of the proton.
33.	Aaron, F. D., et al. (författare) Inclusive photoproduction of rho(0), K(0) and phi mesons at HERA H1 Collaboration 2009 Ingår i:* Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 673:2, s. 119-126 Tidskriftsartikel (refereegranskat)abstract Inclusive non-diffractive photoproduction of rho(770)(0), K*(892)(0) and phi(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average gamma p centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5 < p(T) < 7 GeV and the rapidity range vertical bar y(lab)vertical bar < 1. Differential cross sections are presented as a function of transverse momentum and rapidity, and are compared to the predictions of hadroproduction models. (C) 2009 Elsevier B.V. All rights reserved.
34.	Aaron, F. D., et al. (författare) Jet production in ep collisions at low Q(2) and determination of alpha(s) 2010 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 67:1-2, s. 1-24 Tidskriftsartikel (refereegranskat)abstract The production of jets is studied in deep-inelastic e(+) p scattering at low negative four momentum transfer squared 5 < Q(2) < 100 GeV2 and at inelasticity 0.2 < y < 0.7 using data recorded by the H1 detector at HERA in the years 1999 and 2000, corresponding to an integrated luminosity of 43.5 pb(-1). Inclusive jet, 2-jet and 3-jet cross sections as well as the ratio of 3-jet to 2-jet cross sections are measured as a function of Q(2) and jet transverse momentum. The 2-jet cross section is also measured as a function of the proton momentum fraction xi. The measurements are well described by perturbative quantum chromodynamics at next-to-leading order corrected for hadronisation effects and are subsequently used to extract the strong coupling as.
35.	Aaron, F. D., et al. (författare) Measurement of diffractive scattering of photons with large momentum transfer at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 672:3, s. 219-226 Tidskriftsartikel (refereegranskat)abstract The first measurement of diffractive scattering of quasi-real photons with large momentum transfer gamma p -> gamma Y, where Y is the proton dissociative system, is made using the H1 detector at HERA. The measurement is performed for initial photon virtualities Q(2) < 0.01 GeV2. Single differential cross sections are Measured as a function of W, the incident photon-proton centre of mass energy, and t, the square of the four-momentum transferred at the proton vertex, in the range 175 < W < 247 GeV and 4 < \|t\| < 36 GeV2. The W dependence is well described by a model based on perturbative QCD using a leading logarithmic approximation of the BFKL evolution. The measured \|t\| dependence is harder than that predicted by the model and those observed in exclusive vector meson production. (C) 2009 Published by Elsevier B.V.
36.	Aaron, F. D., et al. (författare) Measurement of isolated photon production in deep-inelastic scattering at HERA 2008 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 54:3, s. 371-387 Tidskriftsartikel (refereegranskat)abstract The production of isolated photons in deep-inelastic scattering ep -> e gamma X is measured with the H1 detector at HERA. The measurement is performed in the kinematic range of negative four-momentum transfer squared 4 < Q(2)< 150 GeV2 and a mass of the hadronic system W-X > 50 GeV. The analysis is based on a total integrated luminosity of 227 pb(-1). The production cross section of isolated photons with a transverse energy in the range 3 < E-T(gamma)< 10 GeV and pseudorapidity range -1.2
37.	Aaron, F. D., et al. (författare) Measurement of the charm and beauty structure functions using the H1 vertex detector at HERA 2010 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 65:1-2, s. 89-109 Tidskriftsartikel (refereegranskat)abstract Inclusive charm and beauty cross sections are measured in e (-) p and e (+) p neutral current collisions at HERA in the kinematic region of photon virtuality 5a parts per thousand currency signQ (2)a parts per thousand currency sign2000 GeV2 and Bjorken scaling variable 0.0002a parts per thousand currency signxa parts per thousand currency sign0.05. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb(-1). The numbers of charm and beauty events are determined using variables reconstructed by the H1 vertex detector including the impact parameter of tracks to the primary vertex and the position of the secondary vertex. The measurements are combined with previous data and compared to QCD predictions.
38.	Aaron, F. D., et al. (författare) Measurement of the D(+/-) meson production cross section and F-2(c(c)over-bar) at high Q(2) in ep scattering at HERA 2010 Ingår i:* Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 686:2-3, s. 91-100 Tidskriftsartikel (refereegranskat)abstract The inclusive production of D(+/-)(2010) mesons in deep-inelastic e(+/-)p scattering is measured in the kinematic region of photon virtuality 100 < Q(2) < 1000 GeV2 and inelasticity 002 < y < 0 7 Single and double differential cross sections for inclusive D meson production are measured in the visible range defined by vertical bar eta(D)vertical bar < 1 5 and p(gamma)(D) > 1 5 GeV The data were collected by the H1 experiment during the period from 2004 to 2007 and correspond to an integrated luminosity of 351 pb(-1) The charm contribution. F-2(c (c) over bar), to the proton structure function F-2 is determined. The measurements are compared with QCD predictions. (C) 2010 Elsevier B V All rights reserved
39.	Aaron, F. D., et al. (författare) Measurement of the inclusive ep scattering cross section at low Q (2) and x at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 63:4, s. 625-678 Tidskriftsartikel (refereegranskat)abstract A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV2 a parts per thousand currency signQ (2)a parts per thousand currency sign12 GeV2, and low Bjorken x, 5a <...10(-6)a parts per thousand currency signxa parts per thousand currency sign0.02. The result is based on two data sets collected in dedicated runs by the H1 Collaboration at HERA at beam energies of 27.6 GeV and 920 GeV for positrons and protons, respectively. A combination with data previously published by H1 leads to a cross section measurement of a few percent accuracy. A kinematic reconstruction method exploiting radiative ep events extends the measurement to lower Q (2) and larger x. The data are compared with theoretical models which apply to the transition region from photoproduction to deep inelastic scattering.
40.	Aaron, F. D., et al. (författare) Measurement of the proton structure function F-L(x, Q(2)) at low x 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 665:4, s. 139-146 Tidskriftsartikel (refereegranskat)abstract A first measurement is reported of the longitudinal proton structure function FL(X, Q(2)) at the ep collider HERA. It is based on inclusive deep inelastic e(+)p scattering cross section measurements with a positron beam energy of 27.5 GeV and proton beam energies of 920, 575 and 460 GeV. Employing the energy dependence of the cross section, FL is measured in a range of squared four-momentum transfers 12 <= Q2 <=, 90 GeV2 and low Bjorken x 0.00024 <= x <= 0.0036. The F-L values agree with higher order QCD calculations based on parton densities obtained using cross section data previously measured at HERA. (C) 2008 Elsevier B.V. All rights reserved.
41.	Aaron, F. D., et al. (författare) Multi-lepton production at high transverse momenta in ep collisions at HERA 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 668:4, s. 268-276 Tidskriftsartikel (refereegranskat)abstract Processes leading to a final state with at least two high transverse momentum leptons (electrons or muons) are studied using the full e(+/-) p data sample collected by the H1 experiment at HERA. The data correspond to an integrated luminosity of 463 pb(-1). Di-lepton and tri-lepton event classes are investigated. Cross sections of the production of e(+)e(-) and mu(+)mu(-) pairs are derived in a restricted phase space dominated by photon-photon collisions. In general, good agreement is found with Standard Model predictions. Events are observed with a total scalar sum of lepton transverse momenta above 100 GeV where the Standard Model expectation is low. In this region, combining di-lepton and tri-lepton classes, five events are observed in e(+) p collisions, compared to a Standard Model expectation of 0.96 +/- 0.12, while no such event is observed in e(-) p data for 0.64 +/- 0.09 expected. (C) 2008 Elsevier B.V. All rights reserved.
42.	Aaron, F. D., et al. (författare) Multi-leptons with high transverse momentum at HERA 2009 Ingår i: Journal of High Energy Physics. - : Springer Science and Business Media LLC. - 1029-8479. ; :10 Tidskriftsartikel (refereegranskat)abstract Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb(-1). The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e(+)p collision data with a scalar sum of the lepton transverse momenta above 100 GeV while 1.94 +/- 0.17 events are expected. Such events are not observed in e(-)p collisions for which 1.19 +/- 0.12 are predicted. Total visible and differential di-electron and di-muon photoproduction cross sections are extracted in a restricted phase space dominated by photon-photon collisions.
43.	Aaron, F. D., et al. (författare) Observation of the hadronic final state charge asymmetry in high Q(2) deep-inelastic scattering at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 681:2, s. 125-133 Tidskriftsartikel (refereegranskat)abstract A first measurement is presented of the charge asymmetry in the hadronic final state from the hard interaction in deep-inelastic ep neutral current scattering at HERA. The measurement is performed in the range of negative squared four momentum transfer 100 < Q(2) < 8000 GeV2. The difference between the event normalised distributions of the scaled momentum, x(p), for positively and negatively charged particles, measured in the current region of the Breit frame, is studied together with its evolution as a function of Q. The results are compared to Monte Carlo models at the hadron and parton levels. (C) 2009 Elsevier B.V. All rights reserved.
44.	Aaron, F. D., et al. (författare) Prompt photons in photoproduction at HERA 2010 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 66:1-2, s. 17-33 Tidskriftsartikel (refereegranskat)abstract The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb(-1) collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6< E-T(gamma) < 15 GeV and -1.0< eta(gamma) < 2.4, respectively. Cross sections for events with an additional jet are measured as a function of the transverse energy and pseudorapidity of the jet, and as a function of the fractional momenta x(gamma) and x(p) carried by the partons entering the hard scattering process. The correlation between the photon and the jet is also studied. The results are compared with QCD predictions based on the collinear and on the k(T) factorization approaches.
45.	Aaron, F. D., et al. (författare) Search for excited electrons in ep collisions at HERA 2008 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 666:2, s. 131-139 Tidskriftsartikel (refereegranskat)abstract A search for excited electrons is performed using the full e(+/-) p data sample collected by the HI experiment at HERA, corresponding to a total luminosity of 475 pb(-1). The electroweak decays of excited electrons e* -> e gamma, e* -> eZ and e* -> vW with subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for excited electron production is found. Mass dependent exclusion limits on e* production cross sections and on the ratio f/Lambda of the coupling to the compositeness scale are derived within gauge mediated models. These limits extend the excluded region compared to previous excited electron searches. The e* production via contact interactions is also addressed for the first time in ep collisions. (C) 2008 Elsevier B.V. All rights reserved.
46.	Aaron, F. D., et al. (författare) Search for excited quarks in ep collisions at HERA 2009 Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 678:4, s. 335-343 Tidskriftsartikel (refereegranskat)abstract A search for excited quarks is performed using the full e(+/-)p data sample collected by the HI experiment at HERA, corresponding to a total integrated luminosity of 475 pb(-1). The electroweak decays of excited quarks q* -> q gamma. q* -> qZ and q* - qW with Subsequent hadronic or leptonic decays of the W and Z bosons are considered. No evidence for first generation excited quark production is found. Mass dependent exclusion limits on q* production cross sections and on the ratio f/Lambda of the coupling to the compositeness scale are derived Within gauge mediated models. These limits extend the excluded region compared to previous excited quark searches. (C) 2009 Elsevier B.V. All rights reserved.
47.	Aaron, F. D., et al. (författare) Strangeness production at low Q(2) in deep-inelastic ep scattering at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 61:2, s. 185-205 Tidskriftsartikel (refereegranskat)abstract The production of neutral strange hadrons is investigated using deep-inelastic scattering events measured with the H1 detector at HERA. The measurements are made in the phase space defined by the negative four-momentum transfer squared of the photon 2 < Q(2) < 100 GeV2 and the inelasticity 0.1 < y < 0.6. The K-s(0) s and Lambda((Lambda) over bar) production cross sections and their ratios are determined. K-s(0) s production is compared to the production of charged particles in the same region of phase space. The Lambda-(Lambda) over bar asymmetry is also measured and found to be consistent with zero. Predictions of leading order Monte Carlo programs are compared to the data.
48.	Aaron, F. D., et al. (författare) Study of charm fragmentation into D (* +/-) mesons in deep-inelastic scattering at HERA 2009 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 59:3, s. 589-606 Tidskriftsartikel (refereegranskat)abstract The process of charm quark fragmentation is studied using D (* +/-) meson production in deep-inelastic scattering as measured by the H1 detector at HERA. The parameters of fragmentation functions are extracted for QCD models based on leading order matrix elements and DGLAP or CCFM evolution of partons together with string fragmentation and particle decays. Additionally, they are determined for a next-to-leading order QCD calculation in the fixed flavour number scheme using the independent fragmentation of charm quarks to D (* +/-) mesons. Two different regions of phase space are investigated defined by the presence or absence of a jet containing the D (* +/-) meson in the event. The fragmentation parameters extracted for the two phase space regions are found to be different.
49.	Aaron, F. D., et al. (författare) Three- and four-jet production at low x at HERA 2008 Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 54:3, s. 389-409 Tidskriftsartikel (refereegranskat)abstract Three- and four-jet production is measured in deep-inelastic ep scattering at low x and Q(2) with the H1 detector using an integrated luminosity of 44.2 pb(-1). Several phase space regions are selected for the three-jet analysis in order to study the underlying parton dynamics from global topologies to the more restrictive regions of forward jets close to the proton direction. The measurements of cross sections for events with at least three jets are compared to fixed order QCD predictions of O(alpha(2)(s)) and O(alpha(3)(s)) and with Monte Carlo simulation programs where higher order effects are approximated by parton showers. A good overall description is provided by the O(alpha(3)(s)) calculation. Too few events are predicted at the lowest x similar to 10(-4), especially for topologies with two forward jets. This hints to large contributions at low x from initial state radiation of gluons close to the proton direction and unordered in transverse momentum. The Monte Carlo program in which gluon radiation is generated by the colour dipole model gives a good description of both the three- and the four-jet data in absolute normalisation and shape.
50.	Aguado, D. S., et al. (författare) The Fifteenth Data Release of the Sloan Digital Sky Surveys : First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library 2019 Ingår i: Astrophysical Journal Supplement Series. - : Institute of Physics Publishing (IOPP). - 0067-0049 .- 1538-4365. ; 240:2 Tidskriftsartikel (refereegranskat)abstract Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July-2017 July). This is the third data release for SDSS-IV, and the 15th from SDSS (Data Release Fifteen; DR15). New data come from MaNGA-we release 4824 data cubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g., stellar and gas kinematics, emission-line and other maps) from the MaNGA Data Analysis Pipeline, and a new data visualization and access tool we call "Marvin." The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper, we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials, and examples of data use. Although SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V (2020-2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data.

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