Hello, A yearly allocation for the LCRC cluster has been requested with the following updated information: Submitter/PI: Robert Wiringa Project Name: qmc_for_nuclei Division: PHY Project title: Quantum Monte Carlo Calculations of Light Nuclei Associated funding: DOE Office of Nuclear Physics Other Systems: ANL Blue Gene/Q (INCITE 65M hours for 12C studies) Science: This project uses Quantum Monte Carlo [Green's function (GFMC), variational (VMC), cluster VMC, and auxiliary-field diffusion (AFDMC)] methods to compute ground-state and low-lying excited-state expectation values of energies, densities, electroweak transitions and response, spectroscopic overlaps, etc., for light- and medium-mass nuclei and low-energy scattering reactions involving these nuclei. Realistic two- and three-nucleon potentials are used. Our goal is a description of all of these systems using a Hamiltonian that also provides an excellent description of nucleon-nucleon scattering and nucleonic matter. Such a `standard nuclear model' can then be used, for example, to compute low-energy astrophysical reactions which cannot be experimentally measured. We are also actively engaged in making predictions that can and are being tested at experimental facilities such as ATLAS, NSCL, TRIUMF, and JLab. Project description: A) Electromagnetic form factors We are studying a variety of electromagnetic properties and transitions in light p-shell nuclei, including both one- and two-body charge and current operators that include the effect of meson-exchange currents. We are now starting a program to evaluate electromagnetic form factors in nuclei with 6 to 12 nucleons. These will allow us to extract nuclear magnetic radii and Zemach moments, which provide corrections to measurements of nuclear charge distributions in muonic-atom experiments. This work is supporting experiments at Argonne's ATLAS facility, at Jefferson Lab, and at TRIUMF. We expect to use 100,000 core hours for this work in FY16. B) Weak decays of light nuclei In a related development, we are studying the weak decays of light nuclei, including beta-decay in 3H, 6He, 7Li, 8Li, 8B, 9Li and 9C and electron capture in 7Be. The lighter nuclei have been studied previously and the bulk of the experimental value is given by one-body Fermi and Gamow-Teller terms. However, these provide only half the experimental matrix element in A=8,9 nuclei, so we are working to incorporate two-body meson-exchange current contributions and to look at additional terms like weak magnetism. This work is relevant to ongoing experiments at ATLAS and at U. of Washington. We would like 80,000 core hours for this project in FY16. C) A=11,12 nuclei Extensive effort has gone into GFMC calculations of 0+ states in 12C using Intrepid and Mira, but only a few exploratory calculations of other A>10 nuclei have been made. We have made some progress on trial functions for 11B, but other cases like 11Be and 12Be remain to be studied, particularly wave functions that are "clusterized." The VMC codes for these trial functions are running efficiently using a mix of OpenMP inside nodes and MPI between nodes. We would like 60,000 cpu hours for this work in FY16. D) Cluster VMC for medium-mass nuclei In the past year we have revived an old program for cluster VMC calculations of medium-mass nuclei. A major focus has been on incorporating an optimization scheme for finding the best variational wave function parameters for a given nucleus and testing it in 4He where we can compare with our regular VMC code. We have also used the CVMC to evaluate momentum distributions in 16O and 40Ca. Our long term goal is to compute nuclear matrix elements for double-beta decay in 48Ca and for neutrino scattering on 40Ar, which is the preferred target for next-generation neutrino oscillation experiments. We would like 60,000 cpu hours to continue this work in FY16. E) Nuclear Structure with chiral effective field theory Our VMC and GFMC nuclear structure studies have been made almost exclusively with a Hamiltonian consisting of our local coordinate-space Argonne v18 two-nucleon potential and Urbana/Illinois three-nucleon potentials. Over the last decade, an alternative method of constructing nuclear Hamiltonians has been developed by others based on chiral effective field theory, but such potentials have generally been non-local momentum-space models not suitable for use with our methods. However, coordinate-space versions of these potentials are now becoming available, and a postdoc with expertise in this area is now joining. We want to test this alternate type of Hamiltonian's predictions for a full range of binding energy, electroweak transition, and other properties in the A=6-12 nuclei and will need 100,000 cpu hours in FY16 for this purpose. Industry partnership: Project URL: Current FY Hours Used: undetermined amount New FY Requested allocation: 400000 Q1: 100000 Q2: 100000 Q3: 100000 Q4: 100000 Justification: Storage requirements: Thank You, The LCRC Accounts System