511 research outputs found
Annulus Amplitudes in the Minimal Superstring
We study the annulus amplitudes in the (2,4) minimal superstring theory using
the continuum worldsheet approach. Our results reproduce the semiclassical
behavior of the wavefunctions of FZZT-branes recently studied in hep-th/0412315
using the dual matrix model. We also study the multi-point functions of neutral
FZZT-branes and find the agreement between their semiclassical limit and the
worldsheet annulus calculation.Comment: 15 pages, lanlma
Three-dimensional airway volumes and most constricted areas in children
poster abstractObjective: The objectives of this retrospective study using cone beam computed tomography (CBCT) were to determine if there are differences in the volume of various airway segments and the most constricted area (MCA) of children with different dentoskeletal patterns.
Methods: The initial CBCTs of 83 orthodontic patients (30 Angle’s Class I; 26 Class II; and 27 Class III) were collected from a private orthodontic office. Following reliability studies, various parameters of the craniofacial complex, airway volume, and MCA were measured utilizing Dolphin 3D software. Comparisons among the three dental and the skeletal malocclusion classes were performed using one-way ANOVA and Fishers Protected Least Significant. Associations of the airway volumes and the MCA with other parameters were determined using correlation coefficients, accepting p < 0.05 as significant for all tests.
Results: Maxillary right sinus volume was the only airway segment showing significant difference among different dental classes. Maxillary sinus volume also correlated moderately with anterior facial height and mandibular length. No significant differences were found between the MCA and different dentoskeletal classifications.
Conclusions: The only significant difference in airway parameters among the dentoskeletal classes was that the dental Class II subjects had greater right sinus volume than the other classes. Shorter anterior facial height or mandibular length could be indicators for decreased airway volume in children.
Funding: IUSD Graduate Research Committee, IUPUI Three-Dimensional Imaging of the Craniofacial Complex Center, Jarabak Endowed Professorshi
Spacetime Properties of ZZ D-Branes
We study the tachyon and the RR field sourced by the ZZ D-branes in
type 0 theories using three methods. We first use the mini-superspace
approximation of the closed string wave functions of the tachyon and the RR
scalar to probe these fields. These wave functions are then extended beyond the
mini-superspace approximation using mild assumptions which are motivated by the
properties of the corresponding wave functions in the mini-superspace limit.
These are then used to probe the tachyon and the RR field sourced. Finally we
study the space time fields sourced by the ZZ D-branes using the FZZT
brane as a probe. In all the three methods we find that the tension of the
ZZ brane is times the tension of the ZZ brane. The RR
charge of these branes is non-zero only for the case of both and odd,
in which case it is identical to the charge of the brane. As a
consistency check we also verify that the space time fields sourced by the
branes satisfy the corresponding equations of motion.Comment: 32 pages, 4 figures. Clarifications on the principal characterization
of ZZ branes added. Reference adde
Muon counting using silicon photomultipliers in the AMIGA detector of the Pierre Auger observatory
AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of the Pierre Auger Observatory designed to extend its energy range of detection and to directly measure the muon content of the cosmic ray primary particle showers. The array will be formed by an infill of surface water-Cherenkov detectors associated with buried scintillation counters employed for muon counting. Each counter is composed of three scintillation modules, with a 10m(2) detection area per module. In this paper, a new generation of detectors, replacing the current multi-pixel photomultiplier tube (PMT) with silicon photo sensors (aka. SiPMs), is proposed. The selection of the new device and its front-end electronics is explained. A method to calibrate the counting system that ensures the performance of the detector is detailed. This method has the advantage of being able to be carried out in a remote place such as the one where the detectors are deployed. High efficiency results, i.e. 98% efficiency for the highest tested overvoltage, combined with a low probability of accidental counting (similar to 2 %), show a promising performance for this new system
Supermatrix models and multi ZZ-brane partition functions in minimal superstring theories
We study (p,q)=(2,4k) minimal superstrings within the minimal superstring
field theory constructed in hep-th/0611045. We explicitly give a solution to
the W_{1+\infty} constraints by using charged D-instanton operators, and show
that the (m,n)-instanton sector with m positive-charged and n negative-charged
ZZ-branes is described by an (m+n)\times (m+n) supermatrix model. We argue that
the supermatrix model can be regarded as an open string field theory on the
multi ZZ-brane system.Comment: 15 pages, 1 figure, minor chang
Time and Amplitude of Afterpulse Measured with a Large Size Photomultiplier Tube
We have studied the afterpulse of a hemispherical photomultiplier tube for an
upcoming reactor neutrino experiment. The timing, the amplitude, and the rate
of the afterpulse for a 10 inch photomultiplier tube were measured with a 400
MHz FADC up to 16 \ms time window after the initial signal generated by an LED
light pulse. The time and amplitude correlation of the afterpulse shows several
distinctive groups. We describe the dependencies of the afterpulse on the
applied high voltage and the amplitude of the main light pulse. The present
data could shed light upon the general mechanism of the afterpulse.Comment: 11 figure
Branes, Rings and Matrix Models in Minimal (Super)string Theory
We study both bosonic and supersymmetric (p,q) minimal models coupled to
Liouville theory using the ground ring and the various branes of the theory.
From the FZZT brane partition function, there emerges a unified, geometric
description of all these theories in terms of an auxiliary Riemann surface
M_{p,q} and the corresponding matrix model. In terms of this geometric
description, both the FZZT and ZZ branes correspond to line integrals of a
certain one-form on M_{p,q}. Moreover, we argue that there are a finite number
of distinct (m,n) ZZ branes, and we show that these ZZ branes are located at
the singularities of M_{p,q}. Finally, we discuss the possibility that the
bosonic and supersymmetric theories with (p,q) odd and relatively prime are
identical, as is suggested by the unified treatment of these models.Comment: 72 pages, 3 figures, improved treatment of FZZT and ZZ branes, minor
change
The Cap in the Hat: Unoriented 2D Strings and Matrix(-Vector) Models
We classify the possible bosonic and Type 0 unoriented string theories in two
dimensions, and find their dual matrix(-vector) models. There are no RP^2 R-R
tadpoles in any of the models, but many of them possess a massless tachyon
tadpole. Thus all the models we find are consistent two-dimensional string
vacua, but some get quantum corrections to their classical tachyon background.
Where possible, we solve the tadpole cancellation condition, and find all the
tachyon tadpole-free theories.Comment: 34 pages, LaTeX; Errors corrected in some of the open string
representations in tables 1, 2 and 3. References and acknowledgments adde
Two-Dimensional Unoriented Strings And Matrix Models
We investigate unoriented strings and superstrings in two dimensions and
their dual matrix quantum mechanics. Most of the models we study have a tachyon
tadpole coming from the RP^2 worldsheet which needs to be cancelled by a
renormalization of the worldsheet theory. We find evidence that the dual matrix
models describe the renormalized theory. The singlet sector of the matrix
models is integrable and can be formulated in terms of fermions moving in an
external potential and interacting via the Calogero-Moser potential. We show
that in the double-scaling limit the latter system exhibits particle-hole
duality and interpret it in terms of the dual string theory. We also show that
oriented string theories in two dimensions can be continuously deformed into
unoriented ones by turning on non-local interactions on the worldsheet. We find
two unoriented superstring models for which only oriented worldsheets
contribute to the S-matrix. A simple explanation for this is found in the dual
matrix model.Comment: 36 pages, harvmac, 2 eps figure
Measurement of single pi0 production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam
Neutral current single pi0 production induced by neutrinos with a mean energy
of 1.3 GeV is measured at a 1000 ton water Cherenkov detector as a near
detector of the K2K long baseline neutrino experiment. The cross section for
this process relative to the total charged current cross section is measured to
be 0.064 +- 0.001 (stat.) +- 0.007 (sys.). The momentum distribution of
produced pi0s is measured and is found to be in good agreement with an
expectation from the present knowledge of the neutrino cross sections.Comment: 6 pages, 4 figures, Submitted to Phys. Lett.
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