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- Aad, G, et al.
(författare)
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- 2015
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swepub:Mat__t
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- Verhaaren, C. B., et al.
(författare)
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Searches for Long-Lived Particles at the Future FCC-ee
- 2022
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Ingår i: Frontiers in Physics. - : Frontiers Media S.A.. - 2296-424X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The electron-positron stage of the Future Circular Collider, FCC-ee, is a frontier factory for Higgs, top, electroweak, and flavour physics. It is designed to operate in a 100 km circular tunnel built at CERN, and will serve as the first step towards ≥100 TeV proton-proton collisions. In addition to an essential and unique Higgs program, it offers powerful opportunities to discover direct or indirect evidence of physics beyond the Standard Model. Direct searches for long-lived particles at FCC-ee could be particularly fertile in the high-luminosity Z run, where 5 × 1012 Z bosons are anticipated to be produced for the configuration with two interaction points. The high statistics of Higgs bosons, W bosons and top quarks in very clean experimental conditions could offer additional opportunities at other collision energies. Three physics cases producing long-lived signatures at FCC-ee are highlighted and studied in this paper: heavy neutral leptons (HNLs), axion-like particles (ALPs), and exotic decays of the Higgs boson. These searches motivate out-of-the-box optimization of experimental conditions and analysis techniques, which could lead to improvements in other physics searches.
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- Bernardi, G., et al.
(författare)
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The Future Circular Collider : a Summary for the US 2021 Snowmass Process
- 2022
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this white paper for the 2021 Snowmass process, we give a description of the proposed Future Circular Collider (FCC) project and its physics program. The paper summarizes and updates the discussion submitted to the European Strategy on Particle Physics. After construction of an approximately 90 km tunnel, an electron-positron collider based on established technologies allows world-record instantaneous luminosities at center-of-mass energies from the Z resonance up to tt thresholds, enabling a rich set of fundamental measurements including Higgs couplings determinations at the sub percent level, precision tests of the weak and strong forces, and searches for new particles, including dark matter, both directly and via virtual corrections or mixing. Among other possibilities, the FCC-ee will be able to (i) indirectly discover new particles coupling to the Higgs and/or electroweak bosons up to scales around 7 and 50 TeV, respectively; (ii) perform competitive SUSY tests at the loop level in regions not accessible at the LHC; (iii) study heavy-flavor and tau physics in ultra-rare decays beyond the LHC reach, and (iv) achieve the best potential in direct collider searches for dark matter, sterile neutrinos, and axion-like particles with masses up to around 90 GeV. The tunnel can then be reused for a proton-proton collider, establishing record center-of-mass collision energy, allowing unprecedented reach for direct searches for new particles up to the around 50 TeV scale, and a diverse program of measurements of the Standard Model and Higgs boson, including a precision measurement of the Higgs self-coupling, and conclusively testing weakly-interacting massive particle scenarios of thermal relic dark matter.
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- Azzi, S., et al.
(författare)
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On the importance of the band gap bowing in Boron-based III-V ternary alloys
- 2007
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Ingår i: Solid State Communications. - : Elsevier BV. - 0038-1098 .- 1879-2766. ; 144:5-6, s. 245-248
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Tidskriftsartikel (refereegranskat)abstract
- The optical band gap bowing of eighteen III-V compound alloys containing boron is calculated by means of a recent phenomenological model [M. Ferhat, Phys. Status Solidi b 241 (2004) R38]. The optical band gap bowing is found to be strong for the all studied III-V boron alloys. In particular, we find that BNSb shows an important optical band gap bowing of 19.78 eV. Parallel to this, we also introduce ab initio pseudopotential plane wave calculations with large relaxed supercells to check the validity of our phenomenological model for BNSb. This gives an optical bowing of 21.19 eV, in fairly good agreement with the model used. Results suggest that the III-V boron alloys are characterized by a strong competition between the volume deformation (b(VD)), charge transfer (b(CE)), and structural relaxation (b(SR)) effects. For the common cation alloys bVD dominates bCE, and bSR is relatively weak; whereas for the common anion alloys, the structural effect (bSR and bVD) appears to control the total optical band gap bowing.
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- Brigelius-Flohé, R, et al.
(författare)
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The European perspective on vitamin E : Current knowledge and future research
- 2002
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Ingår i: American Journal of Clinical Nutrition. - 0002-9165 .- 1938-3207. ; 76:4, s. 703-716
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Tidskriftsartikel (refereegranskat)abstract
- Vitamin E is indispensible for reproduction in female rats. In humans, vitamin E deficiency primarily causes neurologic dysfunctions, but the underlying molecular mechanisms are unclear. Because of its antioxidative properties, vitamin E is believed to help prevent diseases associated with oxidative stress, such as cardiovascular disease, cancer, chronic inflammation, and neurologic disorders. However, recent clinical trials undertaken to prove this hypothesis failed to verify a consistent benefit. Given these findings, a group of European scientists met to analyze the most recent knowledge of vitamin E function and metabolism. An overview of their discussions is presented in this article, which includes considerations of the mechanisms of absorption, distribution, and metabolism of different forms of vitamin E, including the a-tocopherol transfer protein and a-tocopherol-associated proteins, the mechanism of tocopherol side-chain degradation and its putative interaction with drug metabolism, the usefulness of tocopherol metabolites as biomarkers, and the novel mechanisms of the antiatherosclerotic and anticarcinogenic properties of vitamin E, which involve modulation of cellular signaling, transcriptional regulation, and induction of apoptosis. Clinical trials were analyzed on the basis of the selection of subjects, the stage of disease, and the mode of intake, dosage, and chemical form of vitamin E. In addition, the scarce knowledge on the role of vitamin E in reproduction was summarized. In conclusion, the scientists agreed that the functions of vitamin E were underestimated if one considered only its antioxidative properties. Future research on this essential vitamin should focus on what makes it essential for humans, why the body apparently utilizes a-tocopherol preferentially, and what functions other forms of vitamin E have.
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- van Woudenbergh, Geertruida J., et al.
(författare)
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Tea Consumption and Incidence of Type 2 Diabetes in Europe : The EPIC-InterAct Case-Cohort Study
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:5, s. e36910-
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Tidskriftsartikel (refereegranskat)abstract
- Background: In previous meta-analyses, tea consumption has been associated with lower incidence of type 2 diabetes. It is unclear, however, if tea is associated inversely over the entire range of intake. Therefore, we investigated the association between tea consumption and incidence of type 2 diabetes in a European population. Methodology/Principal Findings: The EPIC-InterAct case-cohort study was conducted in 26 centers in 8 European countries and consists of a total of 12,403 incident type 2 diabetes cases and a stratified subcohort of 16,835 individuals from a total cohort of 340,234 participants with 3.99 million person-years of follow-up. Country-specific Hazard Ratios (HR) for incidence of type 2 diabetes were obtained after adjustment for lifestyle and dietary factors using a Cox regression adapted for a case-cohort design. Subsequently, country-specific HR were combined using a random effects meta-analysis. Tea consumption was studied as categorical variable (0, >0-<1, 1-<4, >= 4 cups/day). The dose-response of the association was further explored by restricted cubic spline regression. Country specific medians of tea consumption ranged from 0 cups/day in Spain to 4 cups/day in United Kingdom. Tea consumption was associated inversely with incidence of type 2 diabetes; the HR was 0.84 [95% CI 0.71, 1.00] when participants who drank >= 4 cups of tea per day were compared with non-drinkers (p(linear) (trend) = 0.04). Incidence of type 2 diabetes already tended to be lower with tea consumption of 1-<4 cups/day (HR = 0.93 [95% CI 0.81, 1.05]). Spline regression did not suggest a non-linear association (p(non-linearity) = 0.20). Conclusions/Significance: A linear inverse association was observed between tea consumption and incidence of type 2 diabetes. People who drink at least 4 cups of tea per day may have a 16% lower risk of developing type 2 diabetes than non-tea drinkers.
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