Variational Calculations using Low-Momentum Potentials with Smooth Cutoffs

Recent variational calculations of the deuteron and the triton illustrate that simple wave function ansatze become more effective after evolving the nucleon-nucleon potential to lower momentum (``V_lowk''). However, wave function artifacts from the use of sharp cutoffs in relative momentum decrease effectiveness for small cutoffs (< 2 fm^-1) and slow down convergence in harmonic oscillator bases. These sharp cutoff artifacts are eliminated when V_lowk is generated using a sufficiently smooth cutoff regulator.Comment: 11 pages, 4 figure

Searches for Stable Strangelets in Ordinary Matter: Overview and a Recent Example

Our knowledge on the possible existence in nature of stable exotic particles depends solely upon experimental observation. Guided by this general principle and motivated by theoretical hypotheses on the existence of stable particles of strange quark matter, a variety of experimental searches have been performed. We provide an introduction to the theoretical hypotheses, an overview of the past searches, and a more detailed description of a recent search for helium-like strangelets in the Earth's atmosphere using a sensitive laser spectroscopy method

Search for a T_20 Analyzer for Deuterons

This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit

Low-momentum interactions with smooth cutoffs

Nucleon-nucleon potentials evolved to low momentum, which show great promise in few- and many-body calculations, have generally been formulated with a sharp cutoff on relative momenta. However, a sharp cutoff has technical disadvantages and can cause convergence problems at the 10-100 keV level in the deuteron and triton. This motivates using smooth momentum-space regulators as an alternative. We generate low-momentum interactions with smooth cutoffs both through energy-independent renormalization group methods and using a multi-step process based on the Bloch-Horowitz approach. We find greatly improved convergence for calculations of the deuteron and triton binding energies in a harmonic oscillator basis compared to results with a sharp cutoff. Even a slight evolution of chiral effective field theory interactions to lower momenta is beneficial. The renormalization group preserves the long-range part of the interaction, and consequently the renormalization of long-range operators, such as the quadrupole moment, the radius and 1/r, is small. This demonstrates that low-energy observables in the deuteron are reproduced without short-range correlations in the wave function.Comment: 29 pages, 19 figure

Evidence for a three-nucleon-force effect in proton-deuteron elastic scattering

Developments in spin-polarized internal targets for storage rings have permitted measurements of 197 MeV polarized protons scattering from vector polarized deuterons. This work presents measurements of the polarization observables A_y, iT_11, and C_y,y in proton-deuteron elastic scattering. When compared to calculations with and without three-nucleon forces, the measurements indicate that three-nucleon forces make a significant contribution to the observables. This work indicates that three-body forces derived from static nuclear properties appear to be crucial to the description of dynamical properties.Comment: 8 pages 2 figures Latex, submitted to Phys. Rev. Letter

Measurements of d+p Elastic Scattering Analyzing Powers at 80 MeV

This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Transport processes investigation: A necessary first step in site scale characterization plans

We propose an approach, which we call the Transport Processes Investigation or TPI, to identify and verify site-scale transport processes and their controls. The TPI aids in the formulation of an accurate conceptual model of flow and transport, an essential first step in the development of a cost effective site characterization strategy. The TPI is demonstrated in the highly complex vadose zone of glacial tills that underlie the Fernald Environmental Remediation Project (FEMP) in Fernald, Ohio. As a result of the TPI, we identify and verify the pertinent flow processes and their controls, such as extensive macropore and fracture flow through layered clays, which must be included in an accurate conceptual model of site-scale contaminant transport. We are able to conclude that the classical modeling and sampling methods employed in some site characterization programs will be insufficient to characterize contaminant concentrations or distributions at contaminated or hazardous waste facilities sited in such media

Looking into the matter of light-quark hadrons

In tackling QCD, a constructive feedback between theory and extant and forthcoming experiments is necessary in order to place constraints on the infrared behaviour of QCD's \beta-function, a key nonperturbative quantity in hadron physics. The Dyson-Schwinger equations provide a tool with which to work toward this goal. They connect confinement with dynamical chiral symmetry breaking, both with the observable properties of hadrons, and hence provide a means of elucidating the material content of real-world QCD. This contribution illustrates these points via comments on: in-hadron condensates; dressed-quark anomalous chromo- and electro-magnetic moments; the spectra of mesons and baryons, and the critical role played by hadron-hadron interactions in producing these spectra.Comment: 11 pages, 7 figures. Contribution to the Proceedings of "Applications of light-cone coordinates to highly relativistic systems - LIGHTCONE 2011," 23-27 May, 2011, Dallas. The Proceedings will be published in Few Body System