377 research outputs found

    Deuteron-equivalent and phase-equivalent interactions within light nuclei

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    Background: Phase-equivalent transformations (PETs) are well-known in quantum scattering and inverse scattering theory. PETs do not affect scattering phase shifts and bound state energies of two-body system but are conventionally supposed to modify two-body bound state observables such as the rms radius and electromagnetic moments. Purpose: In order to preserve all bound state observables, we propose a new particular case of PETs, a deuteron-equivalent transformation (DET-PET), which leaves unchanged not only scattering phase shifts and bound state (deuteron) binding energy but also the bound state wave function. Methods: The construction of DET-PET is discussed; equations defining the simplest DET-PETs are derived. We apply these simplest DET-PETs to the JISP16 NNNN interaction and use the transformed NNNN interactions in calculations of 3^3H and 4^4He binding energies in the No-core Full Configuration (NCFC) approach based on extrapolations of the No-core Shell Model (NCSM) basis space results to the infinite basis space. Results: We demonstrate the DET-PET modification of the npnp scattering wave functions and study the DET-PET manifestation in the binding energies of 3^3H and 4^4He nuclei and their correlation (Tjon line). Conclusions: It is shown that some DET-PETs generate modifications of the central component while the others modify the tensor component of the NNNN interaction. DET-PETs are able to modify significantly the npnp scattering wave functions and hence the off-shell properties of the NNNN interaction. DET-PETs give rise to significant changes in the binding energies of 3^3H (in the range of approximately 1.5 MeV) and 4^4He (in the range of more than 9 MeV) and are able to modify the correlation patterns of binding energies of these nuclei

    Phase structures of strong coupling lattice QCD with overlap fermions at finite temperature and chemical potential

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    We perform the first study of lattice QCD with overlap fermions at finite temperature TT and chemical potential μ\mu. We start from the Taylor expanded overlap fermion action, and derive in the strong coupling limit the effective free energy by mean field approximation. On the (μ,T\mu,T) plane and in the chiral limit, there is a tricritical point, separating the second order chiral phase transition line at small μ\mu and large TT, and first order chiral phase transition line at large μ\mu and small TT

    Strong decays of heavy baryons in Bethe-Salpeter formalism

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    In this paper we study the properties of diquarks (composed of uu and/or dd quarks) in the Bethe-Salpeter formalism under the covariant instantaneous approximation. We calculate their BS wave functions and study their effective interaction with the pion. Using the effective coupling constant among the diquarks and the pion, in the heavy quark limit mQm_Q\to\infty, we calculate the decay widths of ΣQ()\Sigma_Q^{(*)} (Q=c,bQ=c,b) in the BS formalism under the covariant instantaneous approximation and then give predictions of the decay widths Γ(Σb()Λb+π)\Gamma(\Sigma_b^{(*)}\to\Lambda_b+\pi).Comment: 41 pages, 1 figure, LaTex2e, typos correcte

    Nucleon-nucleon interaction in the JJ-matrix inverse scattering approach and few-nucleon systems

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    The nucleon-nucleon interaction is constructed by means of the JJ-matrix version of inverse scattering theory. Ambiguities of the interaction are eliminated by postulating tridiagonal and quasi-tridiagonal forms of the potential matrix in the oscillator basis in uncoupled and coupled waves, respectively. The obtained interaction is very accurate in reproducing the NNNN scattering data and deuteron properties. The interaction is used in the no-core shell model calculations of 3^3H and 4^4He nuclei. The resulting binding energies of 3^3H and 4^4He are very close to experimental values.Comment: Text is revised, new figures and references adde

    NN potentials from inverse scattering in the J-matrix approach

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    An approximate inverse scattering method [7,8] has been used to construct separable potentials with the Laguerre form factors. As an application, we invert the phase shifts of proton-proton in the 1S0^1S_0 and 3P23F2^3P_2-^3F_2 channels and neutron-proton in the 3S13D1^3S_1-^3D_1 channel elastic scattering. In the latter case the deuteron wave function of a realistic npnp potential was used as input.Comment: LaTex2e, 17 pages, 3 Postscript figures; corrected typo

    Left to Their Own Devices: Breakdowns in United States Medical Device Premarket Review

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    Using examples from recent FDA regulatory proceedings, Jonas Hines and colleagues critique the medical device premarket review and identify eight weaknesses in the process that should be remedied

    Gender Disparities: A Medical Detoxification Program

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    Significant gaps exist in health care regarding gender in the United States. Health status, social roles, culturally patterned behavior and access to health care can be influenced by gender. Women have been the primary users of health care and minority women usually have received poorer quality care than Non-Hispanic White (NHW) females. The objectives of this study were to identify gender, racial and ethnic disparities in access to substance abuse treatment in a Texas hospital. Secondary data collected on 1,309 subjects who underwent detoxification were studied. Gender, race/ethnicity, drug of abuse, relapse and financial classification were included in the analysis. Results indicate Hispanic females and Non-Hispanic Black (NHB) females were about 5 and 3.5 more likely than NHW females to use Medicaid services respectively (p \u3c .05). NHW and NHB males were more likely to use Medicare than females (p \u3c .05). NHB and Hispanic females were 5.8 and 2.1 times more likely to receive care for abuse of cocaine when compared to NHW females respectively (p \u3c .05). Hispanic females were 2.3 times more likely to relapse than Non-Hispanic females, and uninsured NHB females were 7.1 times at a higher risk to abuse multiple drugs compare to NHW females (p \u3c .05). Socio-economic factors, lower labor force participation rates, and less financial independence can explain females utilizing more often Medicaid regardless of their race/ethnicity. These results can be also explained by aggressive case management utilization, socio cultural barriers and/or discriminatory practices, both intentional and unintentional

    Inverse scattering J-matrix approach to nucleon-nucleus scattering and the shell model

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    The JJ-matrix inverse scattering approach can be used as an alternative to a conventional RR-matrix in analyzing scattering phase shifts and extracting resonance energies and widths from experimental data. A great advantage of the JJ-matrix is that it provides eigenstates directly related to the ones obtained in the shell model in a given model space and with a given value of the oscillator spacing Ω\hbar\Omega. This relationship is of a particular interest in the cases when a many-body system does not have a resonant state or the resonance is broad and its energy can differ significantly from the shell model eigenstate. We discuss the JJ-matrix inverse scattering technique, extend it for the case of charged colliding particles and apply it to the analysis of nαn\alpha and pαp\alpha scattering. The results are compared with the No-core Shell Model calculations of 5^5He and 5^5Li.Comment: Some text is added following suggestions of a journal refere
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