385 research outputs found

    Time Reversal Invariance Violating and Parity Conserving effects in Neutron Deuteron Scattering

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    Time reversal invariance violating parity conserving effects for low energy elastic neutron deuteron scattering are calculated for meson exchange and EFT-type of potentials in a Distorted Wave Born Approximation, using realistic hadronic wave functions, obtained by solving three-body Faddeev equations in configuration space.Comment: There was a technical mistake in calculations due to singular behavior of Yukawa functions at short range. We corrected the integration algorithm. There were some typos which are corrected. arXiv admin note: text overlap with arXiv:1104.305

    Nab: Measurement Principles, Apparatus and Uncertainties

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    The Nab collaboration will perform a precise measurement of 'a', the electron-neutrino correlation parameter, and 'b', the Fierz interference term in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS, using a novel electric/magnetic field spectrometer and detector design. The experiment is aiming at the 10^{-3} accuracy level in (Delta a)/a, and will provide an independent measurement of lambda = G_A/G_V, the ratio of axial-vector to vector coupling constants of the nucleon. Nab also plans to perform the first ever measurement of 'b' in neutron decay, which will provide an independent limit on the tensor weak coupling.Comment: 12 pages, 6 figures, 1 table, talk presented at the International Workshop on Particle Physics with Slow Neutrons, Grenoble, 29-31 May 2008; to appear in Nucl. Instrum. Meth. in Physics Research

    Parity violation in radiative neutron capture on deuteron

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    Parity violating (PV) effects in neutron-deuteron radiative capture are studied using Desplanques, Donoghue, and Holstein (DDH) and effective field theory weak potentials. The values of PV effects are calculated using wave functions, obtained by solving three-body Faddeev equations in configuration space for phenomenological strong potentials. The relations between physical observables and low-energy constants are presented, and dependencies of the calculated PV effects on strong and weak potentials are discussed. The presented analysis shows the possible reason for the existing discrepancy in PV nuclear data analysis using the DDH approach and reveals a new opportunity to study short range interactions in nuclei

    Neutron Beta Decay Studies with Nab

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    Precision measurements in neutron beta decay serve to determine the coupling constants of beta decay and allow for several stringent tests of the standard model. This paper discusses the design and the expected performance of the Nab spectrometer.Comment: Submitted to Proceedings of the Conference CIPANP12, St.Petersburg, Florida, May 201

    Sub-lattice of Jahn-Teller centers in hexaferrite crystal

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    A novel type of sub-lattice of the Jahn-Teller (JT) centers was arranged in Ti-doped barium hexaferrite BaFe12O19. In the un-doped crystal all iron ions, sitting in five different crystallographic positions, are Fe3+ in the high-spin configuration (S = 5/2) and have a non-degenerate ground state. We show that the electron-donor Ti substitution converts the ions to Fe2+ predominantly in tetrahedral coordination, resulting in doubly-degenerate states subject to the E⊗ e problem of the JT effect. The arranged JT complexes, Fe2+O4, their adiabatic potential energy, non-linear and quantum dynamics, have been studied by means of ultrasound and terahertz-infrared spectroscopies. The JT complexes are sensitive to external stress and applied magnetic field. For that reason, the properties of the doped crystal can be controlled by the amount and state of the JT complexes. © 2020, The Author(s).Deutscher Akademischer Austauschdienst, DAADRussian Foundation for Basic Research, RFBR: 18–02–00332 aDeutscher Akademischer Austauschdienst, DAAD: 91728513Ministry of Education and Science of the Russian Federation, Minobrnauka: 19–53–0401019–72–00055Ministry of Education and Science of the Russian Federation, MinobrnaukaThe authors acknowledge fruitful discussions with A.S. Prokhorov. We acknowledge support of the HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL). At Ural Federal University, the research was supported by the Russian Foundation for Basic Research (18–02–00332 a), UrFU Center of Excellence “Radiation and Nuclear Technologies” (Competitiveness Enhancement Program), the Ministry of Education and Science of the Russian Federation (Program 5–100). In M.N. Miheev Institute of Metal Physics, the research was carried out within the state assignment of the Ministry of Education and Science of the Russian Federation (theme “Electron” No. AAAA-A18–118020190098–5. At South Ural State University, the authors were generally supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0011. The single crystal growth part was supported by Russian Foundation for Basic Research (19–53–04010). At Moscow Institute of Physics and Technology, the work was supported by the Russian Ministry of Education and Science (Program 5–100) and by the German Academic Exchange Service (DAAD) Michael Lomonosov Programm Linie B, 91728513. Time-domain low temperature spectroscopic experiments were financially supported by the Russian Scientific Foundation (19–72–00055)

    The Nab Experiment: A Precision Measurement of Unpolarized Neutron Beta Decay

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    Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ=gA/gV\lambda = g_A / g_V, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter aa with a precision of δa/a=103\delta a / a = 10^{-3} and the Fierz interference term bb to δb=3×103\delta b = 3\times10^{-3} in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ\lambda with a precision of δλ/λ=0.03%\delta \lambda / \lambda = 0.03\% that will allow an evaluation of VudV_{ud} and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.Comment: Presented at PPNS201

    Therapy chronic trichomoniasis at patients with associated urogenital chlamydial infection

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    Present material of problem question therapy chronic trichomoniasis. Study clinical and bacteriological effectiveness basic etiotropic preparation and their combination, used in treatment patients trichomoniasis. Found that the combined application antiprotozoal drugs have a more pronounced effect on kills T. vaginalis and shortens the rehabilitation of the patient

    Dual targeting of the epigenome via FACT complex and histone deacetylase is a potent treatment strategy for DIPG

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    Diffuse intrinsic pontine glioma (DIPG) is an aggressive and incurable childhood brain tumor for which new treatments are needed. CBL0137 is an anti-cancer compound developed from quinacrine that targets facilitates chromatin transcription (FACT), a chromatin remodeling complex involved in transcription, replication, and DNA repair. We show that CBL0137 displays profound cytotoxic activity against a panel of patient-derived DIPG cultures by restoring tumor suppressor TP53 and Rb activity. Moreover, in an orthotopic model of DIPG, treatment with CBL0137 significantly extends animal survival. The FACT subunit SPT16 is found to directly interact with H3.3K27M, and treatment with CBL0137 restores both histone H3 acetylation and trimethylation. Combined treatment of CBL0137 with the histone deacetylase inhibitor panobinostat leads to inhibition of the Rb/E2F1 pathway and induction of apoptosis. The combination of CBL0137 and panobinostat significantly prolongs the survival of mice bearing DIPG orthografts, suggesting a potential treatment strategy for DIPG

    Growth Rate Responses of Missouri and Lower Yellowstone River Fishes to a Latitudinal Gradient

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    Notropis atherinoides, freshwater drums Aplodinotus grunniens, river carpsuckers Carpiodes carpio and saugers Stizostedion canadense collected in 1996-1998 from nine river sections of the Missouri and lower Yellowstone rivers at two life-stages (young-of-the-year and age 1+ years) were significantly different among sections. However, they showed no river-wide latitudinal trend except for age 1+ years emerald shiners that did show a weak negative relation between growth and both latitude and length of growing season. The results suggest growth rates of fishes along the Missouri River system are complex and could be of significance in the management and conservation of fish communities in this altered system
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