334 research outputs found

    Search for composite and exotic fermions at LEP 2

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    A search for unstable heavy fermions with the DELPHI detector at LEP is reported. Sequential and non-canonical leptons, as well as excited leptons and quarks, are considered. The data analysed correspond to an integrated luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172 GeV and 161 GeV. The search for pair-produced new leptons establishes 95% confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2, depending on the channel. The search for singly produced excited leptons and quarks establishes upper limits on the ratio of the coupling of the excited fermio

    Search for charginos in e+e- interactions at sqrt(s) = 189 GeV

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    An update of the searches for charginos and gravitinos is presented, based on a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by combining the chargino searches with neutralino searches at the Z resonance implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure

    Search for lightest neutralino and stau pair production in light gravitino scenarios with stau NLSP

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    Promptly decaying lightest neutralinos and long-lived staus are searched for in the context of light gravitino scenarios. It is assumed that the stau is the next to lightest supersymmetric particle (NLSP) and that the lightest neutralino is the next to NLSP (NNLSP). Data collected with the Delphi detector at centre-of-mass energies from 161 to 183 \GeV are analysed. No evidence of the production of these particles is found. Hence, lower mass limits for both kinds of particles are set at 95% C.L.. The mass of gaugino-like neutralinos is found to be greater than 71.5 GeV/c^2. In the search for long-lived stau, masses less than 70.0 to 77.5 \GeVcc are excluded for gravitino masses from 10 to 150 \eVcc . Combining this search with the searches for stable heavy leptons and Minimal Supersymmetric Standard Model staus a lower limit of 68.5 \GeVcc may be set for the stau mas

    B decays

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    We review the prospects for B decay studies at the LHC. Contributing authors: J. Baines, S.P. Baranov, P. Bartalini, M. Beneke, E. Bouhova, G. Buchalla, I. Caprini, F. Charles, J. Charles, Y. Coadou, P. Colangelo, P. Colrain, J. Damet, F. De Fazio, A. Dighe, H. Dijkstra, P. Eerola, N. Ellis, B. Epp, S. Gadomski, P. Galumian, I. Gavrilenko, S. George, V.M. Ghete, V. Gibson, L. Guy, Y. Hasegawa, P. Iengo, A. Jacholkowska, R. Jones, A. Khodjamirian, E. Kneringer, P. Koppenburg, H. Korsmo, N. Labanca, L. Lellouch, M. Lehto, Y. Lemoigne, J. Libby, J. Matias, S. Mele, M. Misiak, A.M. Nairz, T. Nakada, A. Nikitenko, N. Nikitin, A. Nisati, F. Palla, E. Polycarpo, J. Rademacker, F. Rizatdinova, S. Robins, D. Rousseau, W. Ruckstuhl, M.A. Sanchis, O. Schneider, M. Shapiro, C. Shepherd-Themistocleous, P. Sherwood, L. Smirnova, M. Smizanska, A. Starodumov, N. Stepanov, Z. Xie, N. Zaitse

    Measurement of D0-D0 mixing and search for CP violation in D0→K+K-,π+π- decays with the full Belle data set

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    We report an improved measurement of D0 – D‾0 mixing and a search for CP violation in D0 decays to CP -even final states K+K− and π+π− . The measurement is based on the final Belle data sample of 976 fb −1 . The results are yCP=(1.11±0.22±0.09)% and AΓ=(−0.03±0.20±0.07)% , where the first uncertainty is statistical and the second is systematic

    Measurement of inclusive K*0(892), phi(1020) and K*0_2(1430) production in hadronic Z decays

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    The inclusive production of the neutral vector mesons K*0(892) and φ(1020), and of the tensor meson K2*0(1430), in hadronic decays of the Z has been measured by the DELPHI detector at LEP. The average production rates per hadronic Z decay have been determined to be 0.77 ± 0.08 K*0(892), 0.104 ± 0.008 φ(1020) and 0.079 ± 0.040 K2*0(1430). The ratio of the tensor-to-vector meson production yields, 〈K2*0(1430)〉/〈K *0(892)〉 = 0.10± 0.05, is smaller than the 〈f2(1270)〉/〈ρ0(770)〉 and 〈f2′(1525)〉 /〈φ(1020)〉 ratios measured by DELPHI. The production rates and differential cross sections are compared with the predictions of JETSET 7.4 tuned to the DELPHI data and of HERWIG 5.8. The K*0(892) and φ(1020) data are compatible with model predictions, but a large disagreement is observed for the K2*0(1430)

    EuFe2_2As2_2 under high pressure: an antiferromagnetic bulk superconductor

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    We report the ac magnetic susceptibility χac\chi_{ac} and resistivity ρ\rho measurements of EuFe2_2As2_2 under high pressure PP. By observing nearly 100% superconducting shielding and zero resistivity at PP = 28 kbar, we establish that PP-induced superconductivity occurs at TcT_c \sim~30 K in EuFe2_2As2_2. ρ\rho shows an anomalous nearly linear temperature dependence from room temperature down to TcT_c at the same PP. χac\chi_{ac} indicates that an antiferromagnetic order of Eu2+^{2+} moments with TNT_N \sim~20 K persists in the superconducting phase. The temperature dependence of the upper critical field is also determined.Comment: To appear in J. Phys. Soc. Jpn., Vol. 78 No.

    TOI 122b and TOI 237b: Two Small Warm Planets Orbiting Inactive M Dwarfs Found by TESS

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    We report the discovery and validation of TOI 122b and TOI 237b, two warm planets transiting inactive M dwarfs observed by the Transiting Exoplanet Survey Satellite (TESS). Our analysis shows that TOI 122b has a radius of 2.72 ± 0.18 R ⊕ and receives 8.8 ± 1.0 times Earth's bolometric insolation, and TOI 237b has a radius of 1.44±0.12 R ⊕ and receives 3.7 ± 0.5 times Earth's insolation, straddling the 6.7 Earth insolation that Mercury receives from the Sun. This makes these two of the cooler planets yet discovered by TESS, even on their 5.08 and 5.43 day orbits. Together, they span the small-planet radius valley, providing useful laboratories for exploring volatile evolution around M dwarfs. Their relatively nearby distances (62.23 ± 0.21 pc and 38.11 ± 0.23 pc, respectively) make them potentially feasible targets for future radial velocity follow-up and atmospheric characterization, although such observations may require substantial investments of time on large telescopes

    Vascular Remodeling in Health and Disease

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    The term vascular remodeling is commonly used to define the structural changes in blood vessel geometry that occur in response to long-term physiologic alterations in blood flow or in response to vessel wall injury brought about by trauma or underlying cardiovascular diseases.1, 2, 3, 4 The process of remodeling, which begins as an adaptive response to long-term hemodynamic alterations such as elevated shear stress or increased intravascular pressure, may eventually become maladaptive, leading to impaired vascular function. The vascular endothelium, owing to its location lining the lumen of blood vessels, plays a pivotal role in regulation of all aspects of vascular function and homeostasis.5 Thus, not surprisingly, endothelial dysfunction has been recognized as the harbinger of all major cardiovascular diseases such as hypertension, atherosclerosis, and diabetes.6, 7, 8 The endothelium elaborates a variety of substances that influence vascular tone and protect the vessel wall against inflammatory cell adhesion, thrombus formation, and vascular cell proliferation.8, 9, 10 Among the primary biologic mediators emanating from the endothelium is nitric oxide (NO) and the arachidonic acid metabolite prostacyclin [prostaglandin I2 (PGI2)], which exert powerful vasodilatory, antiadhesive, and antiproliferative effects in the vessel wall

    Mendelian randomization supports bidirectional causality between telomere length and clonal hematopoiesis of indeterminate potential

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    Human genetic studies support an inverse causal relationship between leukocyte telomere length (LTL) and coronary artery disease (CAD), but directionally mixed effects for LTL and diverse malignancies. Clonal hematopoiesis of indeterminate potential (CHIP), characterized by expansion of hematopoietic cells bearing leukemogenic mutations, predisposes both hematologic malignancy and CAD. TERT (which encodes telomerase reverse transcriptase) is the most significantly associated germline locus for CHIP in genome-wide association studies. Here, we investigated the relationship between CHIP, LTL, and CAD in the Trans-Omics for Precision Medicine (TOPMed) program (n = 63,302) and UK Biobank (n = 47,080). Bidirectional Mendelian randomization studies were consistent with longer genetically imputed LTL increasing propensity to develop CHIP, but CHIP then, in turn, hastens to shorten measured LTL (mLTL). We also demonstrated evidence of modest mediation between CHIP and CAD by mLTL. Our data promote an understanding of potential causal relationships across CHIP and LTL toward prevention of CAD
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