121821236
The midpoint transformation in Witten's string field theory
Abstract We study the transformation to midpoint coordinates in Witten's string field theory using a ζ-function regularization. We find that the vertex is well defined and local (in that it makes no explicit reference to the midpoint coordinate) as the regulator is removed. This is in contrast to the heat-kernel regularization previously studied by others. We interpret the locality and unitarity anomalies of the heat-kernel regularization in terms of the associativity anomaly of the vertex. We also study the BRST charge in the same limit, verify that it is well defined, and propose a sense in which it is nilpotent. We then argue that the transformed vertex is BRST invariant. We discuss the structure of the space of states in the transformed theory; physical states are singular as the regulator is removed, suggesting that they be interpreted in a distributional sense.
120159094
Microcanonical cluster approximations
Abstract A method of entropy estimates due to Kikuchi is generalized from Ising systems to Z 2 gauge models. This method is explicitly gauge invariant. The results of the approximation are compared to Monte Carlo data and strong coupling expansions.
37539171
Search for disoriented chiral condensate at the Fermilab Tevatron
We present results from MiniMax (Fermilab T-864), a small test/experiment at the Fermilab Tevatron designed to search for the production of a disoriented chiral condensate (DCC) in p-p(bar sign) collisions at {radical}(s)=1.8 TeV in the forward direction, {approx}3.4<{eta}<{approx}4.2. Data, consisting of 1.3x10{sup 6} events, are analyzed using the robust observables developed in an earlier paper. The results are consistent with generic, binomial-distribution partition of pions into charged and neutral species. Limits on DCC production in various models are presented. (c) 2000 The American Physical Society.
120178876
Constraint algebra of open string field theory in midpoint coordinates
Abstract We study the canonical structure of string field theory in midpoint coordinates. We find the constraint algebra, which consists of second class constraints, together with dependent first class constraints. Exploiting properties of the relevant operators, we show that the constraint algebra is the same in the interacting theory as in the free theory, at least on Fock-space states. We discuss the gauge transformations generated by the first class constraints, and show that they can be used to gauge away unphysical fields.
17332592
Analysis of charged-particle–photon correlations in hadronic multiparticle production
In order to analyze data on joint charged-particle/photon distributions from an experimental search (T-864, MiniMax) for disoriented chiral condensate (DCC) at the Fermilab Tevatron collider, we have identified robust observables, ratios of normalized bivariate factorial moments, with many desirable properties. These include insensitivity to many efficiency corrections and the details of the modeling of the primary pion production, and sensitivity to the production of DCC, as opposed to the generic, binomial-distribution partition of pions into charged and neutral species. The relevant formalism is developed and tested in Monte-Carlo simulations of the MiniMax experimental conditions.
123251238
Harmonic analysis of the relativistic string in spinorial coordinates
The authors present the finite-harmonic solution of the constraint equations of the spinor representation of the relativistic string. Choosing a gauge, they make a harmonic decomposition in the form of a product representation. This finite-harmonic approach is then compared with that of Hughston and Shaw (1988). They describe a recursive method for relating series and product parameters, and comment briefly on the question of a generalization for the infinite harmonic case and on the quantization of such systems.
15184441
A High-Resolution Mosaic of Molecular Gas in Stephan’s Quintet
We present high-resolution 12CO J = 1-0 observations of the molecular gas in the Hickson compact group Stephan's Quintet (HCG 92). Our observations consist of multiple pointings and mosaics covering all the regions where CO and star formation have been detected. Within the 100'' field of view centered on the easternmost tidal tail, we detect three clumps of emission that may be partially resolved at our resolution of 8''; two of these are new detections not previously seen in ISM studies of this region. Two of these clumps lie in the optical tidal tail, while the third lies to the southeast and is coincident with a large H I feature, but it does not correspond to any features at other wavelengths. We also tentatively detect CO emission from the star-forming regions in the "old tail" corresponding to recent star formation activity detected in recent UV and Hα observations. Observations of the rest of the compact group do not show detections, even though strong emission was detected with single-dish telescopes, which suggests that the CO emission originates from a diffuse molecular gas cloud or from at least three separate clumps with separations greater than around 3 kpc.
16833520
The H I Companions of H II Galaxies and Low Surface Brightness Dwarf Galaxies
I study the VLA H I survey of H II galaxies by Taylor et al. and the VLA H I survey of low surface brightness (LSB) dwarf galaxies by Taylor et al. to investigate the role of galaxy interactions in triggering the bursts of massive star formation seen in H II galaxies. Comparing the two surveys, I find that H II galaxies have companions more than twice as often as LSB dwarfs (p = 0.57 for H II galaxies, compared to p = 0.24 for LSB dwarfs). I examine the completeness of the companion samples detected by the two surveys. For the companions to H II galaxies, the sample is likely complete in the distribution of velocity separations from their parent galaxies but is probably missing some companions at large projected linear separations because of the finite size of the VLA primary beam. For the companions of LSB dwarfs, the small number of detections means their distributions in velocity and linear separation are poorly determined, but the LSB dwarfs were observed with the same observational setup as the H II galaxies, so they will have the same levels of completeness. Because the two samples were observed in exactly the same fashion, there will be no relative bias in the number of companions introduced in this way. In addition, the redshift distributions of the two samples are very similar, so there will not be a distance-related relative bias. Thus, I conclude that the difference in the number of H I rich companions is genuine, and signifies a difference in the local, small-scale environments between the two types of galaxy. I search through published galaxy catalogs to determine number of neighbors each galaxy has outside the area of the VLA observations. At these large separations, the number of neighbors is the same, within the errors, for the two types of galaxy. The high rate of companion occurrence at low separations for H II galaxies relative to LSB dwarfs supports the hypothesis that the bursts of star formation are triggered by galaxy interactions.