Novel Quark Fragmentation Functions and the Nucleon's Transversity Distribution

We define twist-two and twist-three quark fragmentation functions in Quantum Chromodynamics (QCD) and study their physical implications. Using this formalism we show how the nucleon's transversity distribution can be measured in single pion inclusive electroproduction.Comment: 10 pages, uses PHYZZX macro package, 2 PostScript figures (added using FIGURES). MIT-CTP-215

FSA field test

The 12 continental remote sites were decommissioned. Testing was consolidated into a five-site network consisting of the four Southern California sites and a new Florida site. 16 kW of new state-of-the-art modules were deployed at the five sites. Testing of the old modules continued at the Goldstone site but as a low-priority item. Array testing of modules is considered. Additional new testing capabilities were added. A battery-powered array data logger is discussed. A final set of failure and degradation data was obtained from the modules

The Theory of the Nucleon Spin

I discuss two topics of current interest in the study of the spin structure of the nucleon. First, I discuss whether there is a sum rule for the components of the nucleon's angular moments. Second, I discuss the measurement of the nucleon's transversity distribution in light of recent results reported by the HERMES collaboration at DESY.Comment: 15 pages, 8 figures, LaTeX using rspublic.cls and BoxedEPS macros; as submitted to Phil Trans A of the Royal Society for forthcoming volume: The Quark Structure of Matter; email correspondence to [email protected]

CMB Likelihood Functions for Beginners and Experts

Although the broad outlines of the appropriate pipeline for cosmological likelihood analysis with CMB data has been known for several years, only recently have we had to contend with the full, large-scale, computationally challenging problem involving both highly-correlated noise and extremely large datasets ($N > 1000$). In this talk we concentrate on the beginning and end of this process. First, we discuss estimating the noise covariance from the data itself in a rigorous and unbiased way; this is essentially an iterated minimum-variance mapmaking approach. We also discuss the unbiased determination of cosmological parameters from estimates of the power spectrum or experimental bandpowers.Comment: Long-delayed submission. In AIP Conference Proceedings "3K Cosmology" held in Rome, Oct 5-10, 1998, edited by Luciano Maiani, Francesco Melchiorri and Nicola Vittorio, 343-347, New York, American Institute of Physics 199

Double-Spin Transverse Asymmetries in Drell-Yan Processes

We calculate the double-spin transverse asymmetries for the Drell-Yan lepton pair production in p-p and p-anti p collisions. We assume the transverse and the longitudinal polarization densities to be equal at a very small scale, as it is suggested by confinement model results. Using a global fit for the longitudinal distributions, we find transverse asymmetries of order of 10^-2 at most, in the accessible kinematic regions.Comment: 8 pages, REVTeX, 6 figures included as file figures.tar.g

Constraints on the large-x d/u ratio from electron-nucleus scattering at x>1

Recently the ratio of neutron to proton structure functions F_2n/F_2p was extracted from a phenomenological correlation between the strength of the nuclear EMC effect and inclusive electron-nucleus cross section ratios at x>1. Within conventional models of nuclear smearing, this "in-medium correction" (IMC) extraction constrains the size of nuclear effects in the deuteron structure functions, from which the neutron structure function F_2n is usually extracted. The IMC data determine the resulting proton d/u quark distribution ratio, extrapolated to x=1, to be 0.23 +- 0.09 with a 90% confidence level. This is well below the SU(6) symmetry limit of 1/2 and significantly above the scalar diquark dominance limit of 0.Comment: 4 pages, 3 figure

The Drell-Yan process and Deep Inelastic Scattering from the lattice

We report on measurements of the h_1 structure function, relevant to calculating cross-sections for the Drell-Yan process. This is a quantity which can not be measured in Deep Inelastic Scattering, it gives additional information on the spin carried by the valence quarks, as well as insights on how relativistic the quarks are.Comment: 3 pages, Latex, 3 figures, espcrc2.sty included, Talk presented at LATTICE96(phenomenology

Perturbative fragmentation of vector colored particle into bound states with a heavy antiquark

The fragmentation function of vector particle into possible bound S-wave states with a heavy antiquark is calculated in the leading order of perturbative QCD for the high energy processes at large transverse momenta with the different behaviour of anomalous chromomagnetic moment. One-loop equations are derived for the evolution of fragmentation function moments, which is caused by the emission of hard gluons by the vector particle. The integrated probabilities of fragmentation are given. The distribution of bound state over the transverse momentum with respect to the axis of fragmentation is calculated in the scaling limit.Comment: 10 pages, Latex file + 4 ps-figure