New Method For Precise Determination Research Articles

New method for precise determination of top quark mass at LHC

A new method to measure the mass of the top quark at the LHC is presented [S. Kawabata, Y. Shimizu, Y. Sumino and H. Yokoya, arXiv:1405.2395 [hep-ph]]. This method uses lepton energy distribution and ideally does not depend on the velocity distribution of the top quark. We perform a simulation analysis of the top quark mass reconstruction using this method at the leading order, taking account of experimental circumstances. We estimate the sensitivity of the mass determination. The results show that this method is viable in realistic experimental conditions and has a possibility to achieve a good accuracy in determining a theoretically well-defined top quark mass by including higher-order corrections.

Definition of Raceway Boundary Using Fractal Theory

The particle velocity contours were obtained by tracking the tracer particles in the raceway region of the COREX melter gasifier model and the contours were irregular. According to the fractal theory, the fractal dimensions of different particle velocity contours were determined. Through the analysis of the fractal dimensions, a new method for precise determination of the raceway boundary was proposed. The results show that, when the velocity is less than 0.18 m/s, the particles are located in the stagnant zone and the fractal dimensions of particle velocity contours are almost constant as 1.41; when the velocity increases from 0.18 to 0.83 m/s, the particles are located in the rapid movement zone and the fractal dimensions decrease gradually from 1.41 to 1.05; when the velocity is greater than 0.83 m/s, the particles are located in the cavity zone and the fractal dimensions are again almost constant as approaching to 1.00. Therefore, the velocity contour of 0.18 m/s, which is critical to distinguish the rapid movement zone and stagnant zone, can be used to define the raceway boundary. Based on this method, the effect of blowing rate on raceway size was calculated and the results show that the penetration depth and height of the raceway increase with the increase of blowing rate.

A new method for precise determination of iron, zinc and cadmium stable isotope ratios in seawater by double-spike mass spectrometry

The study of Fe, Zn and Cd stable isotopes (δ56Fe, δ66Zn and δ114Cd) in seawater is a new field, which promises to elucidate the marine cycling of these bioactive trace metals. However, the analytical challenges posed by the low concentration of these metals in seawater has meant that previous studies have typically required large sample volumes, highly limiting data collection in the oceans. Here, we present the first simultaneous method for the determination of these three isotope systems in seawater, using Nobias PA-1 chelating resin to extract metals from seawater, purification by anion exchange chromatography, and analysis by double spike MC-ICPMS. This method is designed for use on only a single litre of seawater and has blanks of 0.3, 0.06 and <0.03ng for Fe, Zn and Cd respectively, representing a 1–20 fold reduction in sample size and a 4–130 decrease in blank compared to previously reported methods. The procedure yields data with high precision for all three elements (typically 0.02–0.2‰; 1σ internal precision), allowing us to distinguish natural variability in the oceans, which spans 1–3‰ for all three isotope systems. Simultaneous extraction and purification of three metals makes this method ideal for high-resolution, large-scale endeavours such as the GEOTRACES program.

New Method for Precise Determination of the Isovector Giant Quadrupole Resonances in Nuclei

The intense, nearly monoenergetic, 100% polarized γ-ray beams available at the HIγS facility, along with the realization that the E1-E2 interference term that appears in the Compton scattering polarization observable has opposite signs in the forward and backward angles, make it possible to obtain an order-of-magnitude improvement in the determination of the parameters of the isovector giant quadrupole resonance (IVGQR). Accurate IVGQR parameters will lead to a more detailed knowledge of the symmetry energy in the nuclear equation of state which is important for understanding nuclear matter under extreme conditions such as those present in neutron stars. Our new method is demonstrated for the case of (209)Bi.

Development of a new procedure for precise determination of viral aerosol lethal dose (ALD 50) for birds

This paper describes a new method for precise determination of viral aerosol lethal dose (ALD 50) and reports the results obtained for birds exposed by H5N1 Avian influenza A strain under controlled laboratory conditions. The reported method utilizes our recently developed personal bioaerosol sampler capable of monitoring viable virus concentration in the ambient air. Up to six laboratory animals could be located in a specially designed aerosol chamber and exposed in parallel by an airborne strain of interest to generate the amount of data sufficient for representative statistical analysis. A concentration of viable airborne virus was measured by the personal aerosol samplers directly in the breathing zone of each particular bird. The results show a very low inter-sampler variation used for each particular run, which was confirmed by a single factor ANOVA test undertaken for all six personal samplers involved in each experiment. As was shown, the difference in amount of viruses collected by all samplers during each particular run was not statistically significant. It was found that the ALD 50 for approximately 400-g birds exposed to H5N1 Avian influenza A strain A/Chicken/Suzdalka/Nov-11/2005 was around 26.5 FFU (focus forming units).

Effect of chromatic aberration on atomic-resolved spherical aberration corrected STEM images

The effect of the chromatic aberration (Cc) coefficient in a spherical aberration (Cs)- corrected electromagnetic lens on high-resolution high-angle annular dark field (HAADF) scanning transmission electron microscope (STEM) images is explored in detail. A new method for precise determination of the Cc coefficient is demonstrated, requiring measurement of an atomic-resolution one-frame through-focal HAADF STEM image. This method is robust with respect to instrumental drift, sample thickness, all lens parameters except Cc, and experimental noise. It is also demonstrated that semi-quantitative structural analysis on the nanometer scale can be achieved by comparing experimental Cs- corrected HAADF STEM images with their corresponding simulated images when the effects of the Cc coefficient and spatial incoherence are included.

Measuring|Vtd/Vub|(=sinγ/sinβwithin the SM) throughB→Mνν¯ (M=π,K,ρ,K*)decays

We propose a new method for precise determination of |V_{td} / V_{ub}| from the ratios of branching ratios BR(B -> \rho \nu \bar \nu ) / BR(B ->\rho l \nu ) and BR(B -> \pi \nu \bar \nu ) / BR(B -> \pi l \nu ). These ratios depend only on the ratio of the Cabibbo-Kobayashi-Maskawa (CKM) elements |V_{td} / V_{ub}|$ with little theoretical uncertainty, when very small isospin breaking effects are neglected. As is well known, |V_{td} / V_{ub}| equals to (\sin \gamma) / (\sin \beta) for the CKM version of CP-violation within the Standard Model. We also give in detail analytical and numerical results on the differential decay width d\Gamma(B -> K^* \nu \bar \nu ) / dq^2 and the ratio of the differential rates dBR(B -> \rho \nu \bar \nu )/dq^2 / dBR(B -> K^* \nu \bar \nu )/dq^2 as well as BR(B -> \rho \nu \bar \nu ) / BR(B -> K^* \nu \bar \nu) and BR(B -> \pi \nu \bar \nu ) / BR(B -> K \nu \bar \nu).

Brewster angle autocorrelation spectroscopy a new method for precise determination of the tilt angle of amphiphiles in Langmuir monolayers

With Brewster angle autocorrelation spectroscopy involving a combination of Brewster angle microscopy and autocorrelation technique, we present a new method for measurements of the tilt angle of amphiphilic molecules like long chain acids, their esters and long chain alcohols in Langmuir monolayers. Information about the tilt angle behavior is extracted from the plateau height of the autocorrelation function, which is related to the intensity contrast between the different domains of the monolayer.

New method for precise determination of neutron beam polarization

We report the realization of a new method for precise determination of neutron beam polarization. The analyzing system utilizes two analyzers connected by a neutron guide which contains a spin flipper. The entire device can be rotated by 180°, thereby reversing the neutron trajectories through the device. The method has also been used to measure the neutron spin depolarization in the two analyzers. The depolarization is consistent with zero within an uncertainty of 10 −3. As a consequence of this, two additional measurements, made with the device, yield values for the neutron polarization. The observed consistency of the three results suggests an accuracy for the method of 0.2%. We have used this technique to measure the polarization of the 50 × 100 mm 2 cold neutron beam at the vertical channel of the WWR-M reactor with an accuracy of 0.2%.

A New Method For Precise Determination of the Position and Strike of Magnetic Boundaries Using Vector Data of the Geomagnetic Anomaly Field

SUMMARY We present a new method which provides precise determination of the position and strike of magnetic boundaries using vector data of the geomagnetic anomaly field. Assuming a 2-D magnetic structure, the intensity of spatial differential vectors (ISDV) exhibits a peak at the boundary of magnetic structures. the strike of the magnetic boundary is obtained using the fact that the magnetic field is zero in the direction parallel to the boundary. We have also applied this method to 3-D magnetic structures. Our method requires only the relative changes of the three components, which are more accurately measured than their actual magnitudes. We have applied this method to data from the southern Juan de Fuca Ridge obtained on the R/V ‘Hakuho-maru’ expedition in 1988 (KH-88-3). the results are summarized in magnetic boundary strike diagrams (MBSD); these are maps that show the position, strike and character of the magnetic boundaries. MBSD provides valuable information for understanding the magnetic structure of oceanic crust, such as magnetic lineations, pseudo-faults, fracture zones and the central anomaly magnetic high (CAMH). Therefore, relatively few vector magnetic profiles provide information similar to extensive total intensity geomagnetic surveys.