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Normalised multi-differential cross sections for top quark pair ($$\hbox {t}{\bar{\hbox {t}}}$$ ttˉ) production are measured in proton-proton collisions at a centre-of-mass energy of 13$$\,{\text {TeV}}$$ TeV using events contain...
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Normalised multi-differential cross sections for top quark pair ($$\hbox {t}{\bar{\hbox {t}}}$$ ttˉ) production are measured in proton-proton collisions at a centre-of-mass energy of 13$$\,{\text {TeV}}$$ TeV using events containing two oppositely charged leptons. The analysed data were recorded with the CMS detector in 2016 and correspond to an integrated luminosity of $$35.9{\,{\text {fb}}^{-1}} $$ 35.9fb-1. The double-differential $$\hbox {t}{\bar{\hbox {t}}}$$ ttˉ cross section is measured as a function of the kinematic properties of the top quark and of the $$\hbox {t}{\bar{\hbox {t}}}$$ ttˉ system at parton level in the full phase space. A triple-differential measurement is performed as a function of the invariant mass and rapidity of the $$\hbox {t}{\bar{\hbox {t}}}$$ ttˉ system and the multiplicity of additional jets at particle level. The data are compared to predictions of Monte Carlo event generators that complement next-to-leading-order (NLO) quantum chromodynamics (QCD) calculations with parton showers. Together with a fixed-order NLO QCD calculation, the triple-differential measurement is used to extract values of the strong coupling strength $$\alpha _{S}$$ αS and the top quark pole mass ($$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole) using several sets of parton distribution functions (PDFs). The measurement of $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole exploits the sensitivity of the $$\hbox {t}{\bar{\hbox {t}}}$$ ttˉ invariant mass distribution to $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole near the production threshold. Furthermore, a simultaneous fit of the PDFs, $$\alpha _{S}$$ αS, and $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole is performed at NLO, demonstrating that the new data have significant impact on the gluon PDF, and at the same time allow an accurate determination of $$\alpha _{S}$$ αS and $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole. The values $$\alpha _{S}(m_{{\text {Z}}}) = 0.1135{}^{+0.0021}_{-0.0017}$$ αS(mZ)=0.1135-0.0017+0.0021 and $$m_{{\text {t}}}^{{\text {pole}}} = 170.5 \pm 0.8 \,{\text {GeV}} $$ mtpole=170.5±0.8GeV are extracted, which account for experimental and theoretical uncertainties, the latter being estimated from NLO scale variations. Possible effects from Coulomb and soft-gluon resummation near the $$\hbox {t}{\bar{\hbox {t}}}$$ ttˉ production threshold are neglected in these parameter extractions. A rough estimate of these effects indicates an expected correction of $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole of the order of $$+1 \,{\text {GeV}} $$ +1GeV, which can be regarded as additional theoretical uncertainty in the current $$m_{{\text {t}}}^{{\text {pole}}}$$ mtpole extraction.
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The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performan...
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The LHCb detector is a forward spectrometer at the Large Hadron Collider (LHC) at CERN. The experiment is designed for precision measurements of CP violation and rare decays of beauty and charm hadrons. In this paper the performance of the various LHCb sub-detectors and the trigger system are described, using data taken from 2010 to 2012. It is shown that the design criteria of the experiment have been met. The excellent performance of the detector has allowed the LHCb collaboration to publish a wide range of physics results, demonstrating LHCb's unique role, both as a heavy flavour experiment and as a general purpose detector in the forward region.
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The chemical composition of aerosol particles (Dp ≤ 1.5 μm) was measured over the southeast Pacific ocean during the VOCALS-REx experiment between 16~October and 15 November 2008 using the US DOE G-1 aircraft. The objective of th...
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The chemical composition of aerosol particles (Dp ≤ 1.5 μm) was measured over the southeast Pacific ocean during the VOCALS-REx experiment between 16~October and 15 November 2008 using the US DOE G-1 aircraft. The objective of these flights was to gain an understanding of the sources and evolution of these aerosols, and how they interacted with the marine stratus cloud layer that prevails in this region of the globe. Our measurements showed that the marine boundary layer (MBL) aerosol mass was dominated by non-sea-salt SO42?, followed by Na+, Cl?, Org, NH4+, and NO3?, in decreasing order of importance; CH3SO3?1 (MSA), Ca2+, and K+ rarely exceeded their limits of detection of ~0.05 and ~0.15 μg m?3 for anions and cations, respectively. The aerosols were strongly acidic as the NH4+ to SO42? equivalence ratio was typically ? deficits caused by both HNO3 and H2SO4, and were externally mixed with SO42? particles as the AMS detected no NO3? whilst uptake of HNO3 occurred only on SSA particles. The SSA loading as a function of wind speed agreed with that calculated from published relationships, and contributed only a small fraction of the total accumulation mode particle number. Vertical distribution of MBL SSA particles (Dp ≤ ~1.5 μm) was uniform, suggesting a very limited dilution from entrainment of free tropospheric (FT) air. It was inferred that because all of the aerosol species (except SSA) exhibited a strong land-to-sea gradient, they were of continental origin. Comparison of relative changes in median values using LOWESS fits as proxies suggests that (1) an oceanic source of NH3 is present between 72° W and 76° W, and (2) additional organic aerosols from biomass burns or biogenic precursors were emitted from coastal regions south of 31° S, with possible cloud processing, and (3) FT contributions to MBL gas and aerosols were negligible. Positive Matrix Factorization analysis of organic aerosol mass spectra obtained with the AMS showed an HOA on 28 October 2008 but not on 6 November 2008 that we attribute to a more extensive cloud processing on the later date. A highly oxidized OOA factor resembling fulvic acid was found associated with anthropogenic and biogenic sources as well as long range transported biomass burn plumes in the FT air. A sulfur-containing OOA factor identified as MSA was strongly correlated with SO42?, hence anthropogenic. The very low levels of CH3SO3? observed suggest a limited contribution of DMS to SO42? aerosols production during VOCALS.
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This review paper provides a recent overview of current international research that is being conducted into the functional properties of cellulose as a nanomaterial. A particular emphasis is placed on fundamental and applied resea...
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This review paper provides a recent overview of current international research that is being conducted into the functional properties of cellulose as a nanomaterial. A particular emphasis is placed on fundamental and applied research that is being undertaken to generate applications, which are now becoming a real prospect given the developments in the field over the last 20 years. A short introduction covers the context of the work, and definitions of the different forms of cellulose nanomaterials (CNMs) that are most widely studied. We also address the terminology used for CNMs, suggesting a standard way to classify these materials. The reviews are separated out into theme areas, namely healthcare, water purification, biocomposites, and energy. Each section contains a short review of the field within the theme and summarizes recent work being undertaken by the groups represented. Topics that are covered include cellulose nanocrystals for directed growth of tissues, bacterial cellulose in healthcare, nanocellulose for drug delivery, nanocellulose for water purification, nanocellulose for thermoplastic composites, nanocellulose for structurally colored materials, transparent wood biocomposites, supercapacitors and batteries.
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The primitive cohomology of the theta divisor of a principally polarized abelian variety of dimension g contains a Hodge structure of level g - 3 which we call the primal cohomology. The Hodge conjecture predicts that this is cont...
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The primitive cohomology of the theta divisor of a principally polarized abelian variety of dimension g contains a Hodge structure of level g - 3 which we call the primal cohomology. The Hodge conjecture predicts that this is contained in the image, under the Abel-Jacobi map, of the cohomology of a family of curves in the theta divisor. In this paper we use the Prym map to show that this version of the Hodge conjecture is true for the theta divisor of a general abelian fivefold.
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In this paper, we review scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) neutrino detectors. LArTPC neut...
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In this paper, we review scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) neutrino detectors. LArTPC neutrino detectors designed for performing precise long-baseline oscillation measurements with GeV-scale accelerator neutrino beams also have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. In addition, low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final-states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. New physics signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of Beyond the Standard Model scenarios accessible in LArTPC-based searches. A variety of experimental and theory-related challenges remain to realizing this full range of potential benefits. Neutrino interaction cross-sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood, and improved theory and experimental measurements are needed; pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for improving this understanding. There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways. Novel concepts for future LArTPC technology that enhance low-energy capabilities should also be explored to help address these challenges.
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This review focuses on the sedimentary records of polycyclic aromatic hydrocarbons (PAHs) in China and the worldwide. We provide a global image of sedimentary record of PAHs in different regions, including their contents, vertical...
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This review focuses on the sedimentary records of polycyclic aromatic hydrocarbons (PAHs) in China and the worldwide. We provide a global image of sedimentary record of PAHs in different regions, including their contents, vertical profiles, and possible sources. Generally, historical PAHs recorded in China, dominated by biomass burning and domestic coal combustion, are moderate on the global scale with an upward trend while elevated levels of historical PAHs are usually found in developed countries with a downward trend. This review ends with some concerns about historical PAHs in sediments and some directions deserved further efforts.
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The general topological model for interfacial defects is reviewed and expanded, and the role of these defects in the coupled shear - migration of interfaces is explored. We focus on twinning in hexagonal metals for many defect exa...
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The general topological model for interfacial defects is reviewed and expanded, and the role of these defects in the coupled shear - migration of interfaces is explored. We focus on twinning in hexagonal metals for many defect examples. The definition of shuffles within the topological model is presented. The concept of partitioning of the rotational component of elastic distortions at a grain boundary or interphase interface has recently been elucidated. This work shows that rotational coherency has an important role in twinning. The role of disconnections in type II twins is presented. (C) 2016 Elsevier Ltd. All rights reserved.
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For any analytic quasiperiodically forced circle diffeomorphisms (ω,〈p/q, ω〉+εf), where f is fixed and ε is small, we show that if ω is Diophantine and the fibred rotation number of the diffeomorphism remains constant in a ...
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For any analytic quasiperiodically forced circle diffeomorphisms (ω,〈p/q, ω〉+εf), where f is fixed and ε is small, we show that if ω is Diophantine and the fibred rotation number of the diffeomorphism remains constant in a unilateral neighborhood of ε =0 (i.e., there is a unilateral phase-locking at ε =0), then the diffeomorphism has at least one analytic q-invariant torus, provided ε is small enough.
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Higgs boson properties are studied in the four-lepton decay channel (where lepton = e, $$\mu $$ μ ) using 139 $$\hbox {fb}^{-1}$$ fb - 1 of proton–proton collision data recorded at $$\sqrt{s}=$$ s = 13 TeV by the ATLAS experimen...
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Higgs boson properties are studied in the four-lepton decay channel (where lepton = e, $$\mu $$ μ ) using 139 $$\hbox {fb}^{-1}$$ fb - 1 of proton–proton collision data recorded at $$\sqrt{s}=$$ s = 13 TeV by the ATLAS experiment at the Large Hadron Collider. The inclusive cross-section times branching ratio for $$H\rightarrow ZZ^*$$ H → Z Z ? decay is measured to be $$1.34 \pm 0.12$$ 1.34 ± 0.12 pb for a Higgs boson with absolute rapidity below 2.5, in good agreement with the Standard Model prediction of $$1.33 \pm 0.08$$ 1.33 ± 0.08 pb. Cross-sections times branching ratio are measured for the main Higgs boson production modes in several exclusive phase-space regions. The measurements are interpreted in terms of coupling modifiers and of the tensor structure of Higgs boson interactions using an effective field theory approach. Exclusion limits are set on the CP-even and CP-odd ‘beyond the Standard Model’ couplings of the Higgs boson to vector bosons, gluons and top quarks.
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