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Nuclear Theory·nucl-th

Monday·December 4, 2017

7 papers—3 primary·4 cross-listed

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  1. 01

    Scattering using real-time path integrals

    W. N. Polyzou🇺🇸 · Ekaterina Nathanson🇺🇸

    Background: Path integrals are a powerful tool for solving problems in quantum theory that are not amenable to a treatment by perturbation theory. Most path integral computations require an analytic continuation to imaginary time. While imaginary time treatments of scattering are possible, imaginary time is not a natural framework for treating scattering problems. Purpose: To test a recently introduced method for performing direct calculations of scattering observables using real-time path integrals. Methods: The computations are based on a new interpretation of the path integral as the expectation value of a potential functional on a space of continuous paths with respect to a complex probability distribution. The method has the advantage that it can be applied to arbitrary short-range potentials. Results: The new method is tested by applying it to calculate half-shell sharp-momentum transition matrix elements for one-dimensional potential scattering. The calculations for half shell transition operator matrix elements are in agreement with a numerical solution of the Lippmann-Schwinger equation. The computational method has a straightforward generalization to more complicated systems.

    nucl-thhep-lathep-thPRC(2020)·4 citations
  2. 02

    An Initial State with Shear in Peripheral Heavy Ion Collisions

    V.K. Magas🇪🇸 · J. Gordillo🇪🇸 · D. Strottman🇳🇴 · Y.L. Xie🇳🇴 · L.P. Csernai🇳🇴

    In the present work we propose a new initial state model for hydrodynamic simulation of relativistic heavy ion collisions based on Bjorken-like solution applied streak by streak in the transverse plane. Previous fluid dynamical calculations in Cartesian coordinates with an initial state based on a streak by streak Yang-Mills field led for peripheral higher energy collisions to large angular momentum, initial shear flow and significant local vorticity. Recent experiments verified the existence of this vorticity via the resulting polarization of emitted and particles. At the same time parton cascade models indicated the existence of more compact initial state configurations, which we are going to simulate in our approach. The proposed model satisfies all the conservation laws including conservation of a strong initial angular momentum which is present in non-central collisions. As a consequence of this large initial angular momentum we observe the rotation of the whole system as well as the fluid shear in the initial state, which leads to large flow vorticity. Another advantage of the proposed model is that the initial state can be given in both [t,x,y,z] and coordinates, and thus can be tested by all 3+1D hydrodynamical codes which exist in the field.

    nucl-thPRC(2018)·4 citations
  3. 03

    Possibility of shears mechanism due to attractive interaction in the island of 140 region

    S. Rajbanshi

    The present work identify an island in the values of dimensionless parameter as +0.10 +0.55 outside which no magnetic rotational (MR) bands due to the repulsive interaction would be observed. The semi-classical calculations within the hybrid shears mechanism with the principal axis cranking model (HSPAC) reveal the possibility of the shears band due to the attractive interaction for nuclei in A 140 region. Though the limited information exists in literature, the HSPAC calculation exhibits the dipole bands above the 4389-keV and 4160-keV excited states in Sm and Eu nuclei, respectively, demand their candidature of the attractive shears bands. Other interesting consequence of the HSPAC calculations is the increasing nature of the and transition strengths with spin unlike the decreasing nature of the transition strengths ( and values) of the MR bands. Thus measurement of the transition probability has been required on urgent basis to validate the strong candidature of such an extreme excitation mechanism in Sm and Eu nuclei.

    nucl-thnucl-ex1 citation

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first authorsco-authorsvia INSPIRE