4,655 research outputs found
Study of J/psi Production in Jets
No full textThe production of J/psi mesons in jets is studied in the forward region
of proton-proton collisions using data collected with the LHCb detector
at a center-of-mass energy of 13 TeV. The fraction of the jet transverse
momentum carried by the J/psi meson z(J/psi) p(T) (J/psi) / p(T)(jet)
is measured using jets with p(T)(jet) > 20 GeV in the pseudorapidity
range 2.5 < eta(jet) < 4.0. The observed z(J/psi) distribution for J/psi
mesons produced in b-hadron decays is consistent with expectations.
However the results for prompt J/psi production do not agree with
predictions based on fixed-order nonrelativistic QCD. This is the first
measurement of the p(T) fraction carried by prompt J/psi mesons in jets
at any experiment
Planetary Geologic Mappers Annual Meeting : June 12-14, 2018, Knoxville, Tennessee
No full textThe annual Planetary Geologic Mappers meetings are held to allow geologic mappers of funded NASA geological mapping projects or other mapping projects to present the status of mapping efforts and obtain guidance for map process, formatting, submission, and technical review.Institutional Support Lunar and Planetary Institute, Universities Space Research AssociationConvener Devon Burr, Earth and Planetary Sciences Department, University of Tennessee Knoxville ; Science Organizing Committee David Williams, Chair, Arizona State University, Devon Burr, Earth and Planetary Sciences Department, University of Tennessee Knoxville, Robert Jacobsen, Earth and Planetary Sciences Department, University of Tennessee Knoxville, Bradley Thomson, Earth and Planetary Sciences Department, University of Tennessee KnoxvillePARTIAL CONTENTS: Geologic Mapping of Impact Craters and the Mahuea Tholus Construct: A Year Three Progress Report for the Mahuea Tholus (V-49) Quadrangle, Venus / N. P. Lang, M. T. Covley, J. Beltran, K. Rogers, and B. J. Thomson--The Europa Global Geologic Map / E. J. Leonard, D. A. Patthoff, D. A. Senske, and G. C. Collins--Building a Geologic Map of Neptune's Moon Triton / E. S. Martin, D. A. Patthoff, M. T. Bland, T. R. Watters, G. C. Collins, and T. Becker--Updating the Global Map of Titan Fluvial Features and Investigating Downstream Radar Brightness Trends / A. D. Maue, D. M. Burr, J. S. Levy, and E. Nathan--Investigations of Volcanic and Volatile-Driven Processes Northeast of Hellas Basin, Mars / S. C. Mest, D. A. Crown, J. Michalski, F. C. Chuang, / K. Price Blount, and L. F. Bleamaster--Preliminary Volcanic Feature Analysis of Olympus Mons and Ascraeus Mons, Mars / K. J. Mohr, D. A. Williams, W. B. Garry, and J. E. Bleacher--High-Resolution Geologic Mapping in Eastern Candor Chasma: 2018 Status Report / C. H. Okubo--2018 Update on the Geologic Map of the Borealis Quadrangle (H-1) on Mercury / L. R. Ostrach, S. C. Mest, L. M. Prockter, N. E. Petro, and P. K. Byrne--Enigmatic Sedimentary Deposits Within Partially Exhumed Impact Craters in the Aeolis Dorsa Region, Mars: Evidence for Past Crater Lakes / S. E. Peel and D. M. Burr--The Fractal Nature of Planetary Landforms and Implications to Geologic Mapping / S. J. Robbins
Model-Independent Evidence for J/psi p Contributions to Lambda(0)(b) -> J/psi pK(-) Decays
No full textThe data sample of Lambda(0)(b) -> J/psi pK(-) decays acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb(-1), is inspected for the presence of J/psi p or J/psi K- contributions with minimal assumptions about K(-)p contributions. It is demonstrated at more than nine standard deviations that Lambda(0)(b) -> J/psi pK(-) decays cannot be described with K- p contributions alone, and that J/psi K- contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for P-c(+)-> J/psi p charmonium-pentaquark states in the same data sample
Análise da influência da geometria de brocas especiais na furação de chapas finas aeronáuticas
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2010Na indústria aeronáutica a implementação de sistemas automatizados de fabricação vem exigindo processos de fabricação cada vez mais eficientes com o mínimo de intervenções por parte dos operadores. Atualmente o processo de furação vem sendo realizado com maior frequência por robôs ou máquinas especiais em vários segmentos da indústria aeronáutica. Uma das grandes dificuldades em se automatizar completamente este processo no setor aeroespacial se deve à formação de rebarbas durante a furação de chapas de alumínio, que é um material largamente utilizado neste setor. A presença de rebarbas requer a interferência humana pois são necessárias etapas de desmontagem, limpeza de cavacos e rebarbas e remontagem. Não sendo removidas, as rebarbas promovem mau assentamento de partes, pontos de concentração de tensão e corrosão. A etapa de rebarbação e limpeza, que não agrega valor ao produto, impede o trabalho continuo do robô e é responsável por grande parte do tempo de produção. Outro problema recorrente se deve a processos inadequados de furacão que promovem flexões excessivas das chapas de revestimento de aeronaves gerando furos com erros de forma. Este trabalho está voltado para o estudo de geometrias de brocas afim de, gerar o mínimo de rebarbas durante a usinagem de chapas finas de alumínio, de acordo com padrões aeronáuticos. O desenvolvimento das geometrias também visa a redução da flexão das chapas a fim de evitar o espaçamento entre as mesmo, o acúmulo de cavacos e consequentemente a etapa de limpeza. Com este intuito foram desenvolvidas brocas com geometrias especiais, variando-se o projeto da ponta e o ângulo de hélice. Para avaliar o desempenho do processo, as brocas foram testadas com diferentes parâmetros de corte e comparadas com uma broca convencionalmente utilizada na indústria aeronáutica. Para análise do desempenho foram utilizados os parâmetros altura de rebarba, força de avanço, momento torçor e a flexão das chapas
Evidence for a New Structure in the J /ψp and J /ψ p ¯ Systems in Bs0 →J /ψp p ¯ Decays
No full textAn amplitude analysis of flavor-untagged Bs0→J/ψpp¯ decays is performed using a sample of 797±31 decays reconstructed with the LHCb detector. The data, collected in proton-proton collisions between 2011 and 2018, correspond to an integrated luminosity of 9 fb-1. Evidence for a new structure in the J/ψp and J/ψp¯ systems with a mass of 4337-4+7 -2+2 MeV and a width of 29-12+26 -14+14 MeV is found, where the first uncertainty is statistical and the second systematic, with a significance in the range of 3.1 to 3.7σ, depending on the assigned JP hypothesis
Experimental investigation on micromilling of oxygen-free, high-conductivity copper using tungsten carbide, chemistry vapour deposition and single-crystal diamond micro tools
No full textInsufficient experimental data from various micro tools limit industrial application
of the micromilling process. This paper presents an experimental comparative investigation into micromilling of oxygen-free, high-conductivity copper using tungsten carbide (WC), chemistry vapour deposition (CVD) diamond, and single-crystal diamond micromilling tools at a uniform 0.4mm diameter. The experiments were carried out on an ultra-precision micromilling
machine that features high dynamic accurate performance, so that the dynamic effect
of the machine tool itself on the cutting process can be reduced to a minimum. Micromachined surface roughness and burr height were characterized using white light interferometry, a scanning electron microscope (SEM), and a precision surface profiler. The influence of variation of cutting parameters, including cutting speeds, feedrate, and axial depth of cut, on surface roughness and burr formation were analysed. The experimental results show that there exists an optimum feedrate at which best surface roughness can be achieved. Optical quality surface roughness can be achieved with CVD and natural diamond tools by carefully selecting machining conditions, and surface roughness, Ra, of the order of 10nm can also be obtained when using micromilling using WC tools on the precision micromilling machine.EU FP6 MASMICRO projec
Evidence for exotic hadron contributions to decays
No full textAll figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-015.htmlInternational audienceA full amplitude analysis of decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV collisions, corresponding to an integrated luminosity of 3 fb. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations , either the and states, previously observed in decays, or the state, previously reported in decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the and production rates expected from their previous observation taking account of Cabibbo suppression
Model-independent evidence for J/ψp contributions to Λ0b → J/ψpK- decays
No full textThe data sample of Λ0b → J/ψpK- decays acquired with the LHCb detector from 7 and 8 TeV pp collisions, corresponding to an integrated luminosity of 3 fb−1, is inspected for the presence of J/ψp or J/ψK− contributions with minimal assumptions about K−p contributions. It is demonstrated at more than nine standard deviations that Λ0b → J/ψpK- decays cannot be described with K−p contributions alone, and that J/ψp contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for P+c→J/ψp charmonium-pentaquark states in the same data sample
The safety and effectiveness of different methods of ear wax removal: a systematic review and economic evaluation
No full textEar wax (cerumen) is a natural secretion produced to protect the inner ear from dirt and other fragments by moving these particles towards the outer ear. If this process does not happen properly, wax may build up causing blockage in the ear canal and the possibility of impaction. People with a build up of ear wax may suffer from hearing loss, discomfort and, on occasions, infection. It may present problems in assessing hearing, blocking the view of the ear drum during medical examination and interfering with the fitting or function of hearing aids. Although it is thought to affect between 2% and 6% of the population in the England and Wales, some groups may be at a higher risk, such as those using hearing aids or with small ear canals and/or skin conditions. Recurrence is thought to be high among some of these groups. The consequences of the build up of ear wax in the ear canal are thought to be a common reason for consultation and cost in general practice with over 2 million consultations per year in the NHS.Methods of removal of ear wax include drops, flushing with water in general practice, and removal with suction or probes in specialist clinics. The relative safety and benefits of these different methods of removal remains uncertain. This research will systematically review published and unpublished evidence on the clinical and cost effectiveness of different methods for the removal of ear wax. Where appropriate, it will develop an economic model using data from this systematic review and other relevant sources to estimate the relative costs and benefits of different methods. In addition, the project will provide recommendations for future research to try to help answer any remaining areas of uncertainty
Fraction of decays in prompt production measured in pPb collisions at TeV
No full textThe fraction of and decays in the prompt
yield, , is measured by
the LHCb detector in pPb collisions at TeV. The study
covers the forward () and backward () rapidity
regions, where is the rapidity in the nucleon-nucleon
center-of-mass system. Forward and backward rapidity samples correspond to
integrated luminosities of 13.6 0.3 nb and 20.8 0.5
nb, respectively. The result is presented as a function of the
transverse momentum in the range 1 GeV/.
The fraction at forward rapidity is compatible with the LHCb
measurement performed in collisions at TeV, whereas the
result at backward rapidity is 2.4 larger than in the forward region
for GeV/. The increase of at low at backward rapidity is compatible with the suppression of the
(2S) contribution to the prompt yield. The lack of in-medium
dissociation of states observed in this study sets an upper limit of
180 MeV on the free energy available in these pPb collisions to dissociate or
inhibit charmonium state formation.Comment: All figures and tables, along with machine-readable versions and any
supplementary material and additional information, are available at
https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-028.html (LHCb
public pages
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