Scalar Quarkonium Masses and Mixing with the Lightest Scalar Glueball

We evaluate the continuum limit of the valence (quenched) approximation to the mass of the lightest scalar quarkonium state, for a range of different quark masses, and to the mixing energy between these states and the lightest scalar glueball. Our results support the interpretation of $f_0(1710)$ as composed mainly of the lightest scalar glueball.Comment: 14 pages of Latex, 5 PostScript figure

Chiral field theory of 0−+0^{-+} glueball

A chiral field theory of $0^{-+}$ glueball is presented. By adding a $0^{-+}$ glueball field to a successful Lagrangian of chiral field theory of pseudoscalar, vector, and axial-vector mesons, the Lagrangian of this theory is constructed. The couplings between the pseodoscalar glueball field and mesons are via U(1) anomaly revealed. Qualitative study of the physical processes of the $0^{-+}$ glueball of $m=1.405\textrm{GeV}$ is presented. The theoretical predictions can be used to identify the $0^{-+}$ glueball.Comment: 29 page

Luminescence quenching of the triplet excimer state by air traces in gaseous argon

While developing a liquid argon detector for dark matter searches we investigate the influence of air contamination on the VUV scintillation yield in gaseous argon at atmospheric pressure. We determine with a radioactive alpha-source the photon yield for various partial air pressures and different reflectors and wavelength shifters. We find for the fast scintillation component a time constant tau1= 11.3 +- 2.8 ns, independent of gas purity. However, the decay time of the slow component depends on gas purity and is a good indicator for the total VUV light yield. This dependence is attributed to impurities destroying the long-lived argon excimer states. The population ratio between the slowly and the fast decaying excimer states is determined for alpha-particles to be 5.5 +-0.6 in argon gas at 1100 mbar and room temperature. The measured mean life of the slow component is tau2 = 3.140 +- 0.067 microsec at a partial air pressure of 2 x 10-6 mbar.Comment: 7 pages submitted to NIM

Digital computer design of compensation for linear control systems

If a control system is to be synthesized, it is inferred that a plant or process is present which must be controlled, and the problem of how to design the control system then arises. The first step is to decide on performance specifications to which the complete system must conform. These specifications may involve such things as the system steady state response, transient response, or frequency response. Any of several synthesis methods may then be applied to complete the system design. In this study a synthesis method is developed for single-loop linear feedback systems. First, the number of compensating poles and zeros and the approximate location of each is determined by conventional methods. A set of functions, one for each specification and one involving each plant pole, is written in terms of the system singularities with the compensation singularity positions as variables and each such function is equated to zero. linear approximations of each of these generally non-linear functions are obtained by expanding each function with a multivariable Taylor series and retaining only linear terms. Expansion is about a point described by the approximate singularity values. This linear set of equations is solved by the Gauss-Jordan elimination method. Due to truncation of the Taylor series, this does not give an exact solution to the original specification equations but will serve as a second approximation which is used as a new point of Taylor series expansion. This iterative process is repeated until a satisfactory solution is found. This entire iterative technique is adapted for digital computer programming and flow charts for such a program are drawn --Abstract, page ii

Performance of the CMS cathode strip chambers with cosmic rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47μm to 243μm. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Charmed Mesons Have No Discernable Color-Coulomb Attraction

Starting with a confining linear Lorentz scalar potential V_s and a Lorentz vector potential V_v which is also linear but has in addition a color-Coulomb attraction piece, -alpha_s/r, we solve the Dirac equation for the ground-state c- and u-quark wave functions. Then, convolving V_v with the u-quark density, we find that the Coulomb attraction mostly disappears, making an essentially linear barV_v for the c-quark. A similar convolution using the c-quark density also leads to an essentially linear tildeV_v for the u-quark. For bound cbar-c charmonia, where one must solve using a reduced mass for the c-quarks, we also find an essentially linear widehatV_v. Thus, the relativistic quark model describes how the charmed-meson mass spectrum avoids the need for a color-Coulomb attraction.Comment: 9 pages, 5 PDF figure