978 research outputs found

    Probing non-perturbative QED and new physics with a LUXE-type experiment at the ILC

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    The proposed LUXE experiment (LASER Und XFEL Experiment) at DESY, Hamburg, using the 16.5 GeV electron beam from the European XFEL, aims to probe QED in the non-perturbative regime created in collisions between high-intensity laser pulses and high-energy electron or photon beams. In this strong-field regime, where the electromagnetic field of the laser is above the Schwinger limit, physical electron-positron pairs will be created from the QED vacuum, similar to Hawking radiation from black holes. LUXE intends to measure the positron production rate in an unprecedented intensity regime, in and beyond the regime expected in the beam-beam interaction of future electron-positron colliders. This setup also provides a unique opportunity to probe physics beyond the standard model by leveraging the large photon flux generated at LUXE, probing axion-like particles (ALPs) at a reach comparable to FASER2 and NA62. In this contribution, we will give an overview of the LUXE experimental setup and its challenges and explore the sensitivity of a LUXE-type experiment using the ILC′'s or another future Higgs factory′'s electron beam instead of the EU.XFEL one.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

    Extracting the top-quark running mass using ttˉt\bar{t}+1-jet events produced at the Large Hadron Collider

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    We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data

    Experimental prospects for precision observables in e−e+→qqˉe^{-}e^{+}\rightarrow q\bar{q} with q=b,cq=b,c processes at the ILC operating at 250 and 500 GeV of center of mass

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    Future Higgs Factories will allow the precise study of e−e+→qqˉe^{-}e^{+}\rightarrow q\bar{q} with q=s,c,b,tq=s,c,b,t interactions at different energies, from the Z-pole up to high energies never reached before. In this contribution, we will discuss the experimental prospects for the measurement of differential observables in e−e+→bbˉe^{-}e^{+}\rightarrow b\bar{b} and e−e+→ccˉe^{-}e^{+}\rightarrow c\bar{c} processes at high energies, 250 and 500 GeV, using full simulation samples and the full reconstruction chain from the ILD concept group. These processes call for superb primary and secondary vertex measurements, a high tracking efficiency to correctly measure the vertex charge and excellent hadron identification capabilities using dE/dxdE/dx. This latter aspect will be discussed in detail together with its implementation within the standard flavour tagging tools developed for ILD (LCFI+). In addition, prospects associated with potential improvements using cluster counting techniques instead of traditional dE/dxdE/dx will be discussed.Comment: This work was carried out in the framework of the ILD concept group. Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

    Experimental methods and prospects on the measurement of electroweak bb and cc-quark observables at the ILC operating at 250 GeV

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    This paper describes a comprehensive experimental study on viability and prospects for the measurement of electroweak observables in e+e−→bbˉe^{+}e^{-}\rightarrow b\bar{b} and e+e−→ccˉe^{+}e^{-}\rightarrow c\bar{c} processes at the International Linear Collider (ILC) operating at 250 GeV of centre of mass energy. The ILC will produce electron and positron beams with different degrees of longitudinal polarisation (up to 80%\% for electrons and 30%30\% for positrons). The studies are based on a detailed simulation of the International Large Detector (ILD) concept. This will allow to inspect in detail the four independent chirality combinations of the electroweak couplings to electrons and other fermions and also perform background free analysis. The ILD design is based on the particle flow approach and the excellent vertexing and tracking capabilities, including charged hadron identification thanks to the dE/dxdE/dx. We evaluate the main sources of experimental systematic uncertainties and identify the key design aspects of the accelerator and detector that are crucial to achieve the required per mil level accuracy that matches the expected statistical accuracy.Comment: 35 pages, 21 figures, ILD concept grou

    Review of real-life teduglutide experience

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    Background: teduglutide is an agonist of glucagon-related peptide (aGLP2) effective as a treatment for patients with short bowel syndrome (SBS), an entity that affects quality of life, usually requires home parenteral nutrition (HPN) and generates significant health costs. The objective of the present narrative review was to assess the real-life experience reported with teduglutide.Methods and results: in real life, one meta-analysis and studies published with 440 patients indicate that Teduglutide is effective after the period of intestinal adaptation after surgery, reducing the need for HPN and in some cases even allowing it to be suspended. The response is heterogeneous, increasing progressively up to 2 years after the start of treatment and reaching 82 % in some series. The presence of colon in continuity is a negative predictor of early response, but a positive predictive factor for the withdrawal of HPN. The most common side effects are gastrointestinal in the early stages of treatment. There are late complications related to the stoma or the occurrence of colon polyps, although the frequency of the latter is very low. In adults, data on improved quality of life and cost-effectiveness are scarce.Conclusions: teduglutide is effective and safe and data from pivotal trials for the treatment of patients with SBS are confirmed in real life and can reduce or even stop HPN in some cases. Although it seems cost-effective, more studies are needed to identify those patients with the greatest benefit

    Two-particle angular correlations in the search for new physics at future e+e−e^+e^- colliders

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    The analysis of angular particle correlations can yield valuable insights into the initial state of matter in high-energy collisions, thereby potentially revealing the existence of Beyond the Standard Model scenarios such as Hidden Valley (HV). In this study, we focus on a QCD-like hidden sector with relatively massive HV quarks (≲100\lesssim 100~GeV) which might enlarge and strengthen azimuthal correlations of final-state SM hadrons. In particular, we study the formation and possible observation of \textit{ridge-like} structures in the angular two-particle correlation function at future e+e−e^+e^- colliders, with a much cleaner environment than in hadron colliders, such as the LHC.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

    Aging enhances contraction to thromboxane A2 in aorta from female senescence mice

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    The time-course for aging-associated effects on vascular reactivity to U46619, a stable analogue of thromboxane A2 (TXA2), was studied in aorta from female senescence-accelerated mice-prone (SAMP8), a murine model of accelerated senescence. SAMP8 and senescence-accelerated mice-resistant (SAMR1) were divided into three groups: 3-, 6- and 10-month-old. Contractile curves to U46619 (10−9 to 10−6 M) were performed in aortic rings in the absence or in the presence of nitric oxide synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 10−4 M) and/or cyclooxygenase (COX) inhibitor indomethacin (10−5 M). Protein and gene expression for COX-1 and COX-2 were determined by immunofluorescence and real-time PCR, respectively. Maximal contraction to U46619 was markedly higher in SAMP8 at all ages. In SAMR1, increases were seen at 10 months, while SAMP8 displays augmented contraction at 6 months, which was further increased at 10 months. L-NAME enhanced U46619 contractions in both 6-month-old groups, although the increase was higher on vessels from SAMR1 at this age. Indomethacin equally increased U46619 contractions in both 3-month-old groups, suggesting the production of vasodilator prostaglandin in young animals. In contrast, at 6 and 10 months indomethacin decreased U46619 contractions in both groups, indicating an aging-associated swap to a release of contractile prostanoids in aorta. In conclusion, aging enhances contractile responses to TXA2 in aorta from female mice by a mechanism involving a decrease of NO production and increased action of contractile prostanoids. This process occurs earlier in SAMP8 mice, establishing these mice as good model to study cardiovascular aging in a convenient and standard time-course

    Sistemas de protección individual anticaídas sometidos a impacto. Simulaciones numéricas

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    Personal fall protection systems are set up by EN-363 to avoid or retain people falls safely (without relevant damages). They are the ultimate resource to prevent a fall after other measures being considered. This paper analyses the variables affecting the system behaviour: free fall height, length of retaining rope, stiffness and damping of retaining material, and worker weight. To this end, fall phenomenon has been simulated with finite elements dynamic models with an elastic rope and a rigid ballast. It allows obtain likely values of maximum forces on the injured and over the system during the impact. Results demonstrate the fundamental role of height fall vs. rope length rate (fall factor), which results more important than the fall height itself. The severe values obtained for maximum forces show that future research would include elastoplastic energy absorbers to decrease impact until reasonable values.Los sistemas anticaída se establecen en UNE-EN-363 para evitar o retener caídas de personas sin que las fuerzas de retención causen daños relevantes. Constituyen el último recurso para prevención de caídas tras considerar otras medidas. Este artículo analiza las variables que afectan al comportamiento del sistema: altura de caída, longitud de cuerda de retención, rigidez y amortiguamiento del material de retención, y peso del operario. A tal fin, el fenómeno ha sido simulado con modelos dinámicos de elementos finitos mediante una cuerda elástica y un lastre rígido. Ello permite obtener valores verosímiles de las máximas fuerzas sobre el accidentado y el sistema durante el impacto. Los resultados demuestran el papel fundamental de la proporción entre altura de caída y longitud de cuerda (factor de caída), más determinante que la propia altura de caída. Las elevadas fuerzas máximas obtenidas indican la necesidad de incluir en el modelo absorbedores de energía elastoplásticos, en futuras investigaciones, con el fin de disminuir el impacto a valores razonables
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