120220028
MiniMax: What has been learned thus far
SummaryA small experiment, «MiniMax», has been set up in the C0 intersection region of the Fermilab Tevatron to seek evidence for disoriented chiral condensates and to study other forward physics phenomena. The experiment consists of a proportional wire chamber telescope accompanied by scintillation (trigger) counters, a lead converter, and followed by an electromagnetic calorimeter. The solid angle accepted is a cone centered at pseudorapidity (η) of 4.1 and of radius (in η-ϕ space) of about 0.6. Over 2.5 million events thus far have demonstrated the successful operation of the apparatus, however to date the analysis has not progressed sufficiently to permit any conclusions concerning disoriented chiral condensates.
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.
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.
119471275
A Chern-Simons-like action for closed-string field theory
A Chern-Simons-like action is proposed for closed-string field theory. The action involves auxiliary fields of arbitrary ghost number and is defined in terms of the closed-string operations integral , Q and, analogous to those introduced by Witten (1986) in the construction of open-string field theory. The action is an extension of one proposed for free closed strings and bears a formal relationship to 2+1 gravity analogous to that between open-string field theory and (2+1)-dimensional Yang-Mills theory.
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.
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.
14490517
Discovery of Molecular Gas in the Outflow and Tidal Arms around M82
We present the first fully sampled map of 12CO (1-0) emission from M82 covering the entire galaxy. Our map contains an ~12 × 15 kpc2 area. We find that extraplanar CO emission, previously reported at short distances above the galactic plane, extends to heights of up to 6 kpc above the disk. Some of this emission is associated with tidal arms seen in H I, implying either that M82 contained substantial amounts of molecular gas in the outer disk or that molecular gas formed after the tidal features. CO emission along the direction of the outflow extends to distances of ~3 kpc above and below the disk. At this distance, the line is shifted in velocity ~100 km s-1 and has the same sense as the galactic outflow from the central starburst. This implies that molecular gas may be entrained into the outflow.
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.