121752579
Precision Lifetime Measurements on Positive and Negative Muons
An experiment to measure and compare the free decay rates of positive and negative muons is described. Muons from the Nevis synchrocyclotron were stopped in a liquid-hydrogen target containing less than 1 ppm ${\mathrm{D}}_{2}$ and less than 1 part in ${10}^{9}$ of other impurities. In this situation, the rate of ${\ensuremath{\mu}}^{\ensuremath{-}}$ capture in ${\mathrm{H}}_{2}$ was the only significant correction to the free decay rate of ${\ensuremath{\mu}}^{\ensuremath{-}}$ and was measured in a separate experiment. The lifetimes were monitored by measuring the time intervals between muon stops and decay electrons using a transistorized digitron of 30-nsec channel width. Electronic circuitry of the "interference remover" type was employed to eliminate time-dependent background. ${\ensuremath{\mu}}^{\ensuremath{-}}$ and ${\ensuremath{\mu}}^{+}$ lifetimes were measured with the same apparatus and under essentially the same conditions of rate and geometry. The ratio of the lifetimes is expected to be particularly insensitive to any systematic errors. We have obtained: ${\ensuremath{\tau}}_{{\ensuremath{\mu}}^{\ensuremath{-}}}=2.198\ifmmode\pm\else\textpm\fi{}0.002$ \ensuremath{\mu}sec (hydrogen correction made), ${\ensuremath{\tau}}_{{\ensuremath{\mu}}^{+}}=2.197\ifmmode\pm\else\textpm\fi{}0.002$ \ensuremath{\mu}sec, $R=\frac{{\ensuremath{\tau}}_{{\ensuremath{\mu}}^{\ensuremath{-}}}}{{\ensuremath{\tau}}_{{\ensuremath{\mu}}^{+}}}=1.000\ifmmode\pm\else\textpm\fi{}0.001$.
121141376
Charged Multiplicity Associated with Transverse Momentum of a Leading Proton in pp at 28.5 GEV/C
We have measured the mean charged multiplicity nCH as a function of transverse momentum p⊥ of the forward proton in the reaction p + p ⇒ p + MM for five intervals of missing mass MM using our Multiparticle Argo Spectrometer System. We observe an increase of nCH for p⊥ > 1 GeV/c.
139640917
Effects of Channel Failure Rates on the Jet Reconstruction Efficiencies an Resolutions in an Fe HF Calorimeter
125174279
Design and performance of the multiparticle argo spectrometer system
Abstract The Multiparticle Argo Spectrometer System, MASS, consists of a magnetic vertex spectrometer, two external trigger spectrometers, an on-line monitoring system and an off-line data analysis chain. The performance of MASS has been evaluated from physics data taken in a study of 28.5 GeV/ c pp collisions covering a large range of transverse momentum.
121981552
Observation and study of centrally produced pion clusters in 28. 5-GeV/c p-p interactions
A double-arm spectrometer is used to identify a pion cluster produced in central p-p collisions at 28.5 GeV/c. Cluster properties studied are angular momentum, quantum statistics, multiplicity, and effective mass. There is some speculation on the production mechanism. (AIP)
124078930
Muon Capture in Hydrogen
Abstract : An experiment to measure the muon capture rate in liquid hydrogen was carried out using scintillation counter techniques. The experiment tests muon-electron universality in interaction with a proton at a momentum transfer of 100 MeV/c. The use of ultra-pure liquid hydrogen, a purified muon beam, neutron-gamma ray discriminating detectors and oscilloscope photography made possible the detection of the 5.2 MeV neutron from the relatively improbable capture reaction (mu + p yields n + nu). The muon molecular formation rate was measured in an independent experiment, but the present result is relatively insensitive to it. The stability of the muon molecular ortho state against transitions to the para ground state for times comparable to the free muon life-time is confirmed. The experimental result of the capture rate measurement, 464 + or - 42 per second is compared with 562 + or - 60 per second, the rate expected on the basis of the conserved vector current theory, muon-electron universality and the accepted value of the "induced pseudo scalar" coupling constant.
119312110
Shape space methods for quantum cosmological triangleland
With toy modelling of conceptual aspects of quantum cosmology and the problem of time in quantum gravity in mind, I study the classical and quantum dynamics of the pure-shape (i.e. scale-free) triangle formed by 3 particles in 2-d. I do so by importing techniques to the triangle model from the corresponding 4 particles in 1-d model, using the fact that both have 2-spheres for shape spaces, though the latter has a trivial realization whilst the former has a more involved Hopf (or Dragt) type realization. I furthermore interpret the ensuing Dragt-type coordinates as shape quantities: a measure of anisoscelesness, the ellipticity of the base and apex’s moments of inertia, and a quantity proportional to the area of the triangle. I promote these quantities at the quantum level to operators whose expectation and spread are then useful in understanding the quantum states of the system. Additionally, I tessellate the 2-sphere by its physical interpretation as the shape space of triangles, and then use this as a back-cloth from which to read off the interpretation of dynamical trajectories, potentials and wavefunctions. I include applications to timeless approaches to the problem of time and to the role of uniform states in quantum cosmological modelling.
18221317
Emergent semiclassical time in quantum gravity: II. Full geometrodynamics and minisuperspace examples
I apply the preceding paper's emergent semiclassical time approach to geometrodynamics. The analogy between the two papers is useful at the level of the quadratic constraints, while I document the differences between the two due to the underlying differences in their linear constraints. I find that the emergent time-dependent wave equation for the universe in general not a time-dependent Schrodinger equation but rather a more general equation containing second time derivatives, and estimate in which regime this becomes significant. I provide a specific minisuperspace example for my emergent semiclassical time scheme and compare it with the hidden York time scheme. Overall, interesting connections are shown between Newtonian, Leibniz-Mach-Barbour, Wentzel-Kramers-Brillouin (WKB) and cosmic times, while the Euler and York hidden dilational times are argued to be somewhat different from these.
17420273
Seminar on Records Theory
In quantum gravity, one seeks to combine quantum mechanics and general relativity. In attempting to do so, one comes across the `problem of time' impasse: the notion of time is conceptually different in each of these theories. In this seminar, I consider the timeless records approach toward resolving this. Records are localized, information-containing subconfigurations of a single instant. Records theory is the study of these and of how science (or history) is to be abstracted from correlations between them. I explain how to motivate this approach, provide a ground-level structure for it and discuss what kind of further tools are needed. For a more comprehensive account with many more references, see [1].
119244537
Quantum cosmological relational model of shape and scale in 1D
Relational particle models are useful toy models for quantum cosmology and the problem of time in quantum general relativity. This paper shows how to extend existing work on concrete examples of relational particle models in 1D to include a notion of scale. This is useful as regards forming a tight analogy with quantum cosmology and the emergent semiclassical time and hidden time approaches to the problem of time. This paper shows furthermore that the correspondence between relational particle models and classical and quantum cosmology can be strengthened using judicious choices of the mechanical potential. This gives relational particle mechanics models with analogues of spatial curvature, cosmological constant, dust and radiation terms. A number of these models are then tractable at the quantum level. These models can be used to study important issues (1) in canonical quantum gravity: the problem of time, the semiclassical approach to it and timeless approaches to it (such as the naive Schr?dinger interpretation and records theory) and (2) in quantum cosmology, such as in the investigation of uniform states, robustness and the qualitative understanding of the origin of structure formation.
118451469
Relational Quadrilateralland. Analogues of Isospin and Hypercharge
I consider the momenta and conserved quantities for CP^2 interpreted as the space of quadrilaterals. This builds on seminar I and II's kinematics via making use of MacFarlane's work considering the SU(3)-like (and thus particle physics-like) conserved quantities that occur for CP^2. I perform the additional step of further interpreting that as the configuration space of all relational quadrilaterals and thus an interesting toy model for whole-universe, relational and geometrodynamical-analogue physics. I also provide the Kuchar observables for the quadrilateral, which is a particular resolution of the Problem of Observables. I study HO-like and highly symmetric potentials. I also provide some exact solutions and qualitative behaviours for dynamics on CP^2. In each case, I reinterpret the results in terms of quadrilaterals. This paves the way for the quantum mechanical study of the relational quadrilateral and for investigations of a number of Problem of Time strategies and of a number of other foundational and qualitative investigations of Quantum Cosmology.