Session A1: Plenary Session

Solar Neutrinos as a Probe of Planetary Formation

The ``solar abundance problem'' is the term used to describe the significant differences between standard solar models tuned to reproduce surface properties, as determined from photoabsorption line analyses, and those tuned to reproduce deep interior properties of the Sun, as determined from helioseismology. I will discuss the possibility that the photoabsorption and helioseismic data are both correct, and that the conflicting results instead reflect a shortcoming in our model of the Sun, namely the standard solar model assumption that the Sun was homogeneous when nuclear fusion first commenced. This speculation connects the solar abundance problem to two other puzzles, chemical differences between the Sun and ``solar twin'' stars and the anomalous composition of Jupiter, which suggest that the interesting chemistry of planetary disks alters both host stars and their planets. I discuss why further exploration of theses questions could be important to searches for exoplanets, and how neutrinos might become one of the explorers's tools.   

Why is the universe accelerating

The remarkable discovery of cosmic acceleration poses two fundamental questions. (1) Does acceleration reflect the presence of a new energy component or the breakdown of General Relativity on cosmological scales? (2) If acceleration is caused by a new energy component, is it constant in space and time as expected for fundamental vacuum energy, or does it show evolution or variation that imply a dynamical field? After briefly reviewing some of the theoretical ideas for explaining cosmic acceleration, I will turn to observational methods for addressing these questions, with emphasis on recent results from baryon acoustic oscillations (BAO) measured in the Sloan Digital Sky Survey and plans for future facilities such as the Dark Energy Survey, BigBOSS, LSST, Euclid, and WFIRST.   

New Perspectives for QCD

AdS/QCD, together with ``Light-Front Holography,'' provides an analytic, frame-independent color-confining first approximation to QCD which is remarkably successful in accounting for light-quark meson and baryon spectroscopy, hadronic form factors, and other hadronic observables. A remarkable holographic feature of hadron dynamics in AdS space in five dimensions is that it is dual to Hamiltonian theory in physical space-time, quantized at fixed light-front time. This light-front holographic principle provides a precise relation between the bound-state amplitudes in AdS space and the boost-invariant light-front wavefunctions describing the internal structure of hadrons in physical space-time. The hadronic eigensolutions of the light-front QCD Hamiltonian satisfy a single-variable relativistic equation of motion, analogous to the nonrelativistic radial Schr\"odinger equation. The color-confining potential is determined uniquely using a method based on conformally invariant quantum mechanics. The resulting potential is color-confining and reproduces the observed linear Regge behavior of the light-quark hadron spectrum in both orbital angular momentum and the radial node number. The pion mass vanishes in the chiral limit, and other features of chiral symmetry are satisfied. The elastic and transition form factors of the pion and the nucleons are also found to be well described in this framework. A number of novel phenomenological consequences will be discussed, including hadronization at the amplitude level. I will also discuss how the renormalization scale of the QCD coupling can be determined by using the ``Principle of Maximum Conformality,'' providing scheme-independent predictions and eliminating an unnecessary source of systematic error in pQCD predictions.