Many-Body Correlation Effects on the Longitudinal Response in the Quasielastic (e, e') Reaction

A study is made of the influence of many-body corrections on the longitudinal response function for the inclusive quasielastic (e, e') reaction. This response function is well known to be suppressed, by about a factor of two, when compared with theoretical predictions based on the concept of single nucleon ejection. This is a characteristic of the data that persists through a wide range of different nuclei and suggests a violation of the Coulomb sum rule. It is here shown how an estimation of the effect of many-body correlations, including a consistent treatment of inelastic final state interactions, can be computed through a relationship to the nuclear optical model. The approximations are such that the Coulomb sum rule in guaranteed to remain satisfied providing the optical potential is hermitian analytic. Calculations of the longitudinal response are carried out within the Fermi Gas Model using phenomenological parameterizations of the nuclear optical potential. The reduction

Relativistic one boson exchange model for the nucleon nucleon interaction

Nucleon-nucleon data below 300-MeV laboratory energy are described by a manifestly covariant wave equation in which one of the intermediate nucleons is restricted to its mass shell. Antisymmetrization of the kernel yields an equation in which the two nucleons are treated in an {ital exactly} symmetric manner, and in which all amplitudes satisfy the Pauli principle {ital exactly}. The kernel is modeled by the sum of one boson exchanges, and four models, all of which fit the data very well ({chi}{sup 2}{congruent}3 per data point) are discussed. Two models require the exchange of {ital only} the {pi}, {sigma}, {rho}, and {omega}, but also require an admixture of {gamma}{sup 5} coupling for the pion, while two other models restrict the pion coupling to pure {gamma}{sup 5}{gamma}{sup {mu}}, but require the exchange of {ital six} mesons, including the {eta}, and a light scalar-isovector meson referred to as {sigma}{sub 1}. Deuteron wave functions resulting from these models are obtained. T

Final State Interactions and Relativistic Effects in the Quasielastic (E,E') Reaction

The longitudinal and transverse response functions for the inclusive quasielastic (e,e') reaction are analyzed in detail.A microscopic theoretical framework for the many-body reaction provides a clear conceptual (nonrelativistic) basis for treating final state interactions and goes far beyond simple plane wave or Hermitean potential models.The many-body physics of inelastic final state channels as described by optical and multiple scattering theories is properly included by incorporating a full complex optical potential.Explicit nonrelativistic and relativistic momentum-space calculations quantitatively demonstrate the importance of such a treatment of final state interactions for both the transverse and longitudinal response.Nonrelativistic calculations are performed using final state interactions based on phenomenology, local density models and microscopic multiple scattering theory.Relativistic calculations span a similar range of models and employ Dirac bound state wave

Conditional MLL-CBP targets GMP and models therapy-related myeloproliferative disease

Chromosomal translocations that fuse the mixed lineage leukemia (MLL) gene with multiple partners typify acute leukemias of infancy as well as therapy-related leukemias. We utilized a conditional knockin strategy to bypass the embryonic lethality caused by MLL-CBP expression and to assess the immediate effects of induced MLL-CBP expression on hematopoiesis. Within days of activating MLL-CBP, the fusion protein selectively expanded granulocyte/macrophage progenitors (GMP) and enhanced their self-renewal/proliferation. MLL-CBP altered the gene expression program of GMP, upregulating a subset of genes including Hox a9. Inhibition of Hox a9 expression by RNA interference demonstrated that MLL-CBP required Hox a9 for its enhanced cell expansion. Following exposure to sublethal γ-irradiation or N-ethyl-N-nitrosourea (ENU), MLL-CBP mice developed myelomonocytic hyperplasia and progressed to fatal myeloproliferative disorders. These represented the spectrum of therapy-induced acute myelomonocytic leukemia/chronic myelomonocytic leukemia/myelodysplastic/myeloproliferative disorder similar to that seen in humans possessing the t(11;16). This model of MLL-CBP therapy-related myeloproliferative disease demonstrates the selectivity of this MLL fusion for GMP cells and its ability to initiate leukemogenesis in conjunction with cooperating mutations