2,516 research outputs found

    Fully-heavy tetraquark production by γγ\gamma \gamma interactions in hadronic collisions at the LHC

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    We investigate the production of the fully - heavy tetraquark states T4QT_{4Q} in the γγ\gamma \gamma interactions present in proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC). We focus on the γγQQ\gamma \gamma \rightarrow {\cal{Q}}{\cal{Q}} (Q=J/ψ,Υ{\cal{Q}} = J/\psi,\, \Upsilon) subprocess, mediated by the T4QT_{4Q} resonance in the ss - channel, and present predictions for the hadronic cross sections considering the kinematical ranges probed by the ALICE and LHCb Collaborations. Our results demonstrate that the experimental study of this process is feasible and can be used to investigate the existence and properties of the T4c(6900)T_{4c}(6900) and T4b(19000)T_{4b}(19000) states.Comment: 5 pages, 2 figures, 2 tables. arXiv admin note: substantial text overlap with arXiv:1809.0812

    Exclusive J/ΨJ/\Psi plus jet associated production in ultraperipheral PbPbPbPb collisions

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    The study of exclusive processes in ultraperipheral collisions at the Large Hadron Collider (LHC) has allowed us to test several aspects of the Standard Model and to search for New Physics. In this letter, we investigate the possibility of using these processes to improve our understanding of the quarkonium production mechanism through the study of the exclusive J/ΨJ/\Psi plus jet associate production in ultraperipheral PbPbPbPb collisions. We estimate the transverse - momentum and rapidity distributions considering that the γγJ/Ψ+X\gamma \gamma \rightarrow J/\Psi + X (X=γ,gX = \gamma, \, g) subprocess is described by the Non - Relativistic QCD (NRQCD) formalism and present predictions for the rapidity ranges covered by central and forward detectors. The experimental separation of these events is discussed and the results indicate that a future experimental analysis is, in principle, feasible in future runs of the LHC and the Future Circular Collider (FCC).Comment: 9 pages, 4 figures, 2 table

    Large differences in gene expression responses to drought and heat stress between elite barley cultivar scarlett and a spanish landrace

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    23 Pags.- 6 Tabls.- 8 Figs. Copyright © 2017 Cantalapiedra, García-Pereira, Gracia, Igartua, Casas and Contreras-Moreira. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forms is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Drought causes important losses in crop production every season. Improvement for drought tolerance could take advantage of the diversity held in germplasm collections, much of which has not been incorporated yet into modern breeding. Spanish landraces constitute a promising resource for barley breeding, as they were widely grown until last century and still show good yielding ability under stress. Here, we study the transcriptome expression landscape in two genotypes, an outstanding Spanish landrace-derived inbred line (SBCC073) and a modern cultivar (Scarlett). Gene expression of adult plants after prolonged stresses, either drought or drought combined with heat, was monitored. Transcriptome of mature leaves presented little changes under severe drought, whereas abundant gene expression changes were observed under combined mild drought and heat. Developing inflorescences of SBCC073 exhibited mostly unaltered gene expression, whereas numerous changes were found in the same tissues for Scarlett. Genotypic differences in physiological traits and gene expression patterns confirmed the different behavior of landrace SBCC073 and cultivar Scarlett under abiotic stress, suggesting that they responded to stress following different strategies. A comparison with related studies in barley, addressing gene expression responses to drought, revealed common biological processes, but moderate agreement regarding individual differentially expressed transcripts. Special emphasis was put in the search of co-expressed genes and underlying common regulatory motifs. Overall, 11 transcription factors were identified, and one of them matched cis-regulatory motifs discovered upstream of co-expressed genes involved in those responses.This work was funded by DGA - Obra Social La Caixa [grant number GA-LC-059-2011] and by the Spanish Ministry of Economy and Competitiveness [projects AGL2010-21929, RFP-2012-00015-00-00 AGL2013-48756-R and AGL2016-80967-R]. Carlos P. Cantalapiedra is funded by [grant BES-2011-045905 linked to project AGL2010-21929].Peer reviewe

    Associated ϕ\phi and J/ΨJ/\Psi photoproduction in ultraperipheral PbPbPbPb collisions at the Large Hadron Collider and Future Circular Collider

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    In this paper we analyze the associated ϕ\phi and J/ΨJ/\Psi photoproduction in ultraperipheral PbPbPbPb collisions through the double scattering mechanism for the energies of the Large Hadron Collider (LHC) and Future Circular Collider (FCC). Our results complement a previous analysis for the ρρ\rho\rho, J/ΨJ/ΨJ/\Psi J/\Psi and ρJ/Ψ\rho J/\Psi production. We present our predictions for the total cross sections and rapidity distributions considering the rapidity ranges covered by the ALICE and LHCb detectors, which indicate that a future experimental analysis of ϕJ/Ψ\phi J/\Psi final state is feasible. These results point out that the study of the double vector meson photoproduction in heavy ion collisions can be useful to constrain the double scattering mechanism and improve our understanding of the QCD dynamics at high energies.Comment: 6 pages, 3 figures, 1 tabl

    Double particle production in ultraperipheral PbPbPbPb collisions at the Large Hadron Collider and Future Circular Collider

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    In this paper we analyze the associated production of a vector meson with a (pseudo)scalar bound state or a dimuon system in ultraperipheral PbPbPbPb collisions through the double scattering mechanism for the energies of the Large Hadron Collider (LHC) and Future Circular Collider (FCC). Our results complement previous studies for the double vector meson production. We present our predictions for the total cross sections and rapidity distributions considering the rapidity ranges covered by the ALICE and LHCb detectors, which indicate that a future experimental analysis of the ϕ+ηc\phi + \eta_c, ϕ+μ+μ\phi + \mu^+ \mu^- and J/Ψ+μ+μJ/\Psi + \mu^+ \mu^- final states is feasible.Comment: 6 pages, 2 figures, 1 table. arXiv admin note: text overlap with arXiv:2210.0486

    Associated vector meson and bound-free electron-positron pair photoproduction in ultraperipheral PbPbPbPb collisions

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    In this letter we analyze the associated production of a vector meson with the bound - free e+ee^+e^- process in ultraperipheral PbPbPbPb collisions through the double scattering mechanism for the energy of the Large Hadron Collider (LHC). Such process is characterized by the presence of a meson and a positron in the final state and by a forward hydrogen - like ion with a distinct electric charge. We present our predictions for the total cross sections and rapidity distributions considering the rapidity ranges covered by the ALICE and LHCb detectors, which indicate that a future experimental analysis of the ϕ+e+\phi + e^+ and J/Ψ+e+J/\Psi + e^+ final states is feasible.Comment: 5 pages, 2 figures, 1 table. arXiv admin note: substantial text overlap with arXiv:2306.0551

    The evaluation of laser weldability of the third-generation advanced high strength steel

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    To meet the demands of vehicular safety and greenhouse gas emission reduction, the automotive industry is increasingly using advanced high strength steels (AHSS) in the production of the components. With the development of the new generation of AHSS, it is essential to study their behavior towards manufacturing processes used in the automotive industry. For this purpose, the welding capability of newly developed third-generation Gen3 980T steel was investigated using the Nd:YAG (Neodymium:Yittrium Aluminum Garnet) laser-welding with different parameter conditions. The analysis was made by uniaxial tensile tests, micro-hardness, Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The criteria used to evaluate the quality of the weld were the distance between the fracture and the weld bead and the surface finish. A relationship between the quality of the weld and the energy density was observed, expressed by a partial penetration for values below the optimal, and by irregularities in the weld bead and a high number of spatters for the values above the optimal.publishe

    Morphological and agronomic characterization of buffel grass of the Germplasm Bank of Cenchrus of the Embrapa Tropical Semi-Arid.

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    The objective of this study was to characterize morphological and agronomic buffel grass accesses the germplasm bank of Cenchrus of the Embrapa Tropical Semi-Arid checking the variability and efficiency of characters in carrier two consecutive cuts

    A multicenter validation of an endoscopic classification with narrow band imaging for gastric precancerous and cancerous lesions

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    BACKGROUND AND STUDY AIM: The reliability and external validity of narrow band imaging (NBI) in the stomach have not been described consistently. The aim of the current study was to describe and estimate the accuracy and reliability of a simplified classification system for NBI in the diagnosis of gastric lesions. METHODS: Consecutive patients undergoing NBI endoscopy at two reference centers (n=85, 33% with dysplasia) were included in two studies. In total, 224 different areas were biopsied and recorded onto video. In the derivation study, previously described NBI features were analyzed in order to develop a simplified classification. In the validation study the accuracy and reliability of this classification were estimated among three groups of endoscopists with different levels of expertise in NBI. .RESULTS: The reliability/accuracy results from the derivation study allowed the creation of a simplified NBI classification. In the validation study, "regular vessels with circular mucosa" (pattern A) was associated with normal histology (accuracy 83%; 95% confidence interval [CI] 75?%-90%); "tubulo-villous mucosa" (pattern B) was associated with intestinal metaplasia (accuracy 84%; 95CI 77%-91%; positive likelihood ratio [LR+]=4.75); and "irregular vessels and mucosa" (pattern C) was associated with dysplasia (accuracy 95%; 95CI 90%-99%; LR+=44.33). The reproducibility of these patterns was high (k=0.62). "Light-blue crest" was moderately reliable (k=0.49) but specific (87%) for intestinal metaplasia. A variable vascular density (additional pattern+) was the best feature for Helicobacter pylori gastritis (accuracy 70%; 95CI 59%-80%) but showed only fair reliability (k=0.38). Non-experienced endoscopists presented lower agreement (k=0.6 vs. k=0.75) and accuracy (74% vs. 86%) than international experts/experienced endoscopists. CONCLUSION: A simplified NBI classification is accurate and reliable for the diagnosis of intestinal metaplasia and dysplasia. The classification should be further assessed and validated on a per-patient assessment of NBI, and by comparing NBI with other imaging technologies.This study was supported by a grant for medical investigation from the Portuguese Digestive Endoscopy Society (SPED 2009 Investigation Grant)
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