82,561 research outputs found

    Heavy Quarkonium Potential Model and the 1P1{}^1P_1 State of Charmonium

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    A theoretical explanation of the observed splittings among the P~states of charmonium is given with the use of a nonsingular potential model for heavy quarkonia. We also show that the recently observed mass difference between the center of gravity of the 3PJ{}^3P_J states and the 1P1{}^1P_1 state of ccˉc\bar{c} does not provide a direct test of the color hyperfine interaction in heavy quarkonia. Our theoretical value for the mass of the 1P1{}^1P_1 state is in agreement with the experimental result, and its E1 transition width is 341.8~keV. The mass of the ηc\eta_c' state is predicted to be 3622.3~MeV.Comment: 15 page REVTEX documen

    Quantum-Chromodynamic Potential Model for Light-Heavy Quarkonia and the Heavy Quark Effective Theory

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    We have investigated the spectra of light-heavy quarkonia with the use of a quantum-chromodynamic potential model which is similar to that used earlier for the heavy quarkonia. An essential feature of our treatment is the inclusion of the one-loop radiative corrections to the quark-antiquark potential, which contribute significantly to the spin-splittings among the quarkonium energy levels. Unlike ccˉc\bar{c} and bbˉb\bar{b}, the potential for a light-heavy system has a complicated dependence on the light and heavy quark masses mm and MM, and it contains a spin-orbit mixing term. We have obtained excellent results for the observed energy levels of D0D^0, DsD_s, B0B^0, and BsB_s, and we are able to provide predicted results for many unobserved energy levels. Our potential parameters for different quarkonia satisfy the constraints of quantum chromodynamics. We have also used our investigation to test the accuracy of the heavy quark effective theory. We find that the heavy quark expansion yields generally good results for the B0B^0 and BsB_s energy levels provided that M1M^{-1} and M1lnMM^{-1}\ln M corrections are taken into account in the quark-antiquark interactions. It does not, however, provide equally good results for the energy levels of D0D^0 and DsD_s, which indicates that the effective theory can be applied more accurately to the bb quark than the cc quark.Comment: 17 pages of LaTeX. To appear in Physical Review D. Complete PostScript file is available via WWW at http://gluon.physics.wayne.edu/wsuhep/jim/heavy.p

    Bc spectroscopy in a quantum-chromodynamic potential model

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    We have investigated BcB_c spectroscopy with the use of a quantum-chromodynamic potential model which was recently used by us for the light-heavy quarkonia. We give our predictions for the energy levels and the EE1 transition widths. We also find, rather surprisingly, that although BcB_c is not a light-heavy system, the heavy quark effective theory with the inclusion of the mb1m_b^{-1} and mb1lnmbm_b^{-1}\ln m_b corrections is as successful for BcB_c as it is for BB and BsB_s.Comment: 10 page ReVTeX pape

    Indian GDP, 1600-1871 : some preliminary estimates and a comparison with Britain.

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    This paper provides estimates of Indian GDP constructed from the output side for the period 1600-1871, and combines them with population estimates to track changes in living standards. Indian per capita GDP declined steadily. As British living standards increased from the mid-seventeenth century, India fell increasingly behind. Whereas in 1650, Indian per capita GDP was more than 80 per cent of the British level, by 1871 it had fallen to less than 15 per cent. As well as placing the origins of the Great Divergence firmly in the early modern period, these estimates suggest a relatively prosperous India at the height of the Mughal Empire, with living standards well above bare bones subsistence

    Real-time flutter analysis

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    The important algorithm issues necessary to achieve a real time flutter monitoring system; namely, the guidelines for choosing appropriate model forms, reduction of the parameter convergence transient, handling multiple modes, the effect of over parameterization, and estimate accuracy predictions, both online and for experiment design are addressed. An approach for efficiently computing continuous-time flutter parameter Cramer-Rao estimate error bounds were developed. This enables a convincing comparison of theoretical and simulation results, as well as offline studies in preparation for a flight test. Theoretical predictions, simulation and flight test results from the NASA Drones for Aerodynamic and Structural Test (DAST) Program are compared

    Linear Phase Second Order Recursive Digital Integrators and Differentiators

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    In this paper, design of linear phase second order recursive digital integrators and differentiators is discussed. New second order integrators have been designed by using Genetic Algorithm (GA) optimization method. Thereafter, by modifying the transfer function of these integrators appropriately, new digital differentiators have been obtained. The proposed digital integrators and differentiators accurately approximate the ideal ones and have linear phase response over almost entire Nyquist frequency range. The proposed operators also outperform the existing operators in terms of both magnitude and phase response
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