248 research outputs found
One-electron states and interband optical absorption in single-wall carbon nanotubes
Explicit expressions for the wave functions and dispersion equation for the
band p - electrons in single-wall carbon nanotubes are obtained within the
method of zero-range potentials. They are then used to investigate the
absorption spectrum of polarized light caused by direct interband transitions
in isolated nanotubes. It is shown that, at least, under the above
approximations, the circular dichroism is absent in chiral nanotubes for the
light wave propagating along the tube axis. The results obtained are compared
with those calculated in a similar way for a graphite plane.Comment: 16 pages, 8 figures, 1 tabl
Measurement of Muon Capture on the Proton to 1% Precision and Determination of the Pseudoscalar Coupling g_P
The MuCap experiment at the Paul Scherrer Institute has measured the rate L_S
of muon capture from the singlet state of the muonic hydrogen atom to a
precision of 1%. A muon beam was stopped in a time projection chamber filled
with 10-bar, ultra-pure hydrogen gas. Cylindrical wire chambers and a segmented
scintillator barrel detected electrons from muon decay. L_S is determined from
the difference between the mu- disappearance rate in hydrogen and the free muon
decay rate. The result is based on the analysis of 1.2 10^10 mu- decays, from
which we extract the capture rate L_S = (714.9 +- 5.4(stat) +- 5.1(syst)) s^-1
and derive the proton's pseudoscalar coupling g_P(q^2_0 = -0.88 m^2_mu) = 8.06
+- 0.55.Comment: Updated figure 1 and small changes in wording to match published
versio
Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling
The rate of nuclear muon capture by the proton has been measured using a new
experimental technique based on a time projection chamber operating in
ultra-clean, deuterium-depleted hydrogen gas at 1 MPa pressure. The capture
rate was obtained from the difference between the measured
disappearance rate in hydrogen and the world average for the decay
rate. The target's low gas density of 1% compared to liquid hydrogen is key to
avoiding uncertainties that arise from the formation of muonic molecules. The
capture rate from the hyperfine singlet ground state of the atom is
measured to be , from which the induced
pseudoscalar coupling of the nucleon, , is
extracted. This result is consistent with theoretical predictions for
that are based on the approximate chiral symmetry of QCD.Comment: submitted to Phys.Rev.Let
Inorganic Nanocarriers Based on Calcium Carbonate and Silica Oxide for Passive Breast Cancer Targeting
Received: 26.04.2024. Revised: 03.05.2024. Accepted: 03.05.2024. Available online: 21.05.2024.CaCO3 and SiO2 NPs can be a platform for delivery to breast cancer.Controlling the size and structure of CaCO3 and SiO2 NPs allows maintaining their efficient accumulation in a tumor.CaCO3 and SiO2 NPs accumulated in the breast cancer tumor with 1.62% ± 0.3% and 2.48% ± 0.4% ID/g, respectively.Nanoparticles (NPs) are widely used platforms for delivery of various biologically active compounds. Unfortunately, there is a lack of comprehensive investigations that would include a few types of NPs with different physicochemical parameters and their potential use as delivery systems in one tumor model. Therefore, to achieve therapeutic effect via nanocarrier with therapeutic agent, the properties of the developed NPs must be clearly defined. Herein, we report the development and modification of 99mTc and Cy5-labeled NPs based on calcium carbonate (CaCO3) and silica oxide (SiO2) to investigate in vitro and in vivo distribution on an example of a breast cancer model. We describe the synthesis and characterization of these NPs, including their morphology, size distribution, stability in biological media and cytotoxicity. Transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), direct radiometry analysis, and histology were used to collect all data. The cellular uptake of NPs on 4T1 cell line was shown in vitro and in vivo. As a result, we demonstrated that these NPs are non-toxic, biocompatible, and stable system to use for delivery of bioactive compounds into breast cancer.This work was supported by the Russian Science Foundation (grant no. 24-25-00210), https://rscf.ru/project/24-25-00210/
Muon (g-2) Technical Design Report
The Muon (g-2) Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment a factor-of-four more precisely than was done in E821 at the Brookhaven National Laboratory AGS. The E821 result appears to be greater than the Standard-Model prediction by more than three standard deviations. When combined with expected improvement in the Standard-Model hadronic contributions, E989 should be able to determine definitively whether or not the E821 result is evidence for physics beyond the Standard Model. After a review of the physics motivation and the basic technique, which will use the muon storage ring built at BNL and now relocated to Fermilab, the design of the new
experiment is presented. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2/3 approval
Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm
We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision
Mu2e Technical Design Report
The Mu2e experiment at Fermilab will search for charged lepton flavor
violation via the coherent conversion process mu- N --> e- N with a sensitivity
approximately four orders of magnitude better than the current world's best
limits for this process. The experiment's sensitivity offers discovery
potential over a wide array of new physics models and probes mass scales well
beyond the reach of the LHC. We describe herein the preliminary design of the
proposed Mu2e experiment. This document was created in partial fulfillment of
the requirements necessary to obtain DOE CD-2 approval.Comment: compressed file, 888 pages, 621 figures, 126 tables; full resolution
available at http://mu2e.fnal.gov; corrected typo in background summary,
Table 3.
Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment
The Deep Underground Neutrino Experiment (DUNE) will produce world-leading
neutrino oscillation measurements over the lifetime of the experiment. In this
work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in
the neutrino sector, and to resolve the mass ordering, for exposures of up to
100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed
uncertainties on the flux prediction, the neutrino interaction model, and
detector effects. We demonstrate that DUNE will be able to unambiguously
resolve the neutrino mass ordering at a 3 (5) level, with a 66
(100) kt-MW-yr far detector exposure, and has the ability to make strong
statements at significantly shorter exposures depending on the true value of
other oscillation parameters. We also show that DUNE has the potential to make
a robust measurement of CPV at a 3 level with a 100 kt-MW-yr exposure
for the maximally CP-violating values \delta_{\rm CP}} = \pm\pi/2.
Additionally, the dependence of DUNE's sensitivity on the exposure taken in
neutrino-enhanced and antineutrino-enhanced running is discussed. An equal
fraction of exposure taken in each beam mode is found to be close to optimal
when considered over the entire space of interest
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