9,850 research outputs found

    Finite formation time effects in inclusive and semi-inclusive electro-disintegration of few-body nuclei

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    Finite Formation Time (FFT) effects in the exclusive reaction ^4He(e,e'p)^3H at high values of Q^2 are introduced and discussed. It is shown that the minimum in the momentum distributions predicted by the Plane Wave Impulse Approximation (PWIA), which is filled by the Glauber-type Final State Interaction (FSI), is completely recovered when FFT effects are taken into account. The semi-inclusive process ^4 He(e,e'p)X is also investigated.Comment: 4 pages, 2 eps figure

    Quaternion Octonion Reformulation of Quantum Chromodynamics

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    We have made an attempt to develop the quaternionic formulation of Yang - Mill's field equations and octonion reformulation of quantum chromo dynamics (QCD). Starting with the Lagrangian density, we have discussed the field equations of SU(2) and SU(3) gauge fields for both cases of global and local gauge symmetries. It has been shown that the three quaternion units explain the structure of Yang- Mill's field while the seven octonion units provide the consistent structure of SU(3)_{C} gauge symmetry of quantum chromo dynamics

    Imaginary in all directions: an elegant formulation of special relativity and classical electrodynamics

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    A suitable parameterization of space-time in terms of one complex and three quaternionic imaginary units allows Lorentz transformations to be implemented as multiplication by complex-quaternionic numbers rather than matrices. Maxwell's equations reduce to a single equation.Comment: 8 page

    Signatures of foliated surface bundles and the symplectomorphism groups of surfaces

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    AbstractFor any closed oriented surface Σg of genus g⩾3, we prove the existence of foliated Σg-bundles over surfaces such that the signatures of the total spaces are non-zero. We can arrange that the total holonomy of the horizontal foliations preserve a prescribed symplectic form ω on the fiber. We relate the cohomology class represented by the transverse symplectic form to a crossed homomorphism Flux:SympΣg→H1(Σg;R) which is an extension of the flux homomorphism Flux:Symp0Σg→H1(Σg;R) from the identity component Symp0Σg to the whole group SympΣg of symplectomorphisms of Σg with respect to the symplectic form ω

    Residue network in protein native structure belongs to the universality class of three dimensional critical percolation cluster

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    A single protein molecule is regarded as a contact network of amino-acid residues. Some studies have indicated that this network is a small world network (SWN), while other results have implied that this is a fractal network (FN). However, SWN and FN are essentially different in the dependence of the shortest path length on the number of nodes. In this paper, we investigate this dependence in the residue contact networks of proteins in native structures, and show that the networks are not SWN but FN. FN is generally characterized by several dimensions. Among them, we focus on three dimensions; the network topological dimension DcD_c, the fractal dimension DfD_f, and the spectral dimension DsD_s. We find that proteins universally yield Dc≈1.9D_c \approx 1.9, Df≈2.5D_f \approx 2.5 and Ds≈1.3Ds \approx 1.3. These values are in surprisingly good coincidence with those in three dimensional critical percolation cluster. Hence the residue contact networks in the protein native structures belong to the universality class of three dimensional percolation cluster. The criticality is relevant to the ambivalent nature of the protein native structures, i.e., the coexistence of stability and instability, both of which are necessary for a protein to function as a molecular machine or an allosteric enzyme.Comment: 4 pages, 3 figure

    Calculations of Branching Ratios for Radiative-Capture, One-Proton, and Two-Neutron Channels in the Fusion Reaction 209^{209}Bi+70^{70}Zn

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    We discuss the possibility of the non-one-neutron emission channels in the cold fusion reaction 70^{70}Zn + 209^{209}Bi to produce the element Z=113. For this purpose, we calculate the evaporation-residue cross sections of one-proton, radiative-capture, and two-neutron emissions relative to the one-neutron emission in the reaction 70^{70}Zn + 209^{209}Bi. To estimate the upper bounds of those quantities, we vary model parameters in the calculations, such as the level-density parameter and the height of the fission barrier. We conclude that the highest possibility is for the 2n reaction channel, and its upper bounds are 2.4% and at most less than 7.9% with unrealistic parameter values, under the actual experimental conditions of [J. Phys. Soc. Jpn. {\bf 73} (2004) 2593].Comment: 6 pages, 4 figure
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