120490697
Special function solutions of a spectral problem for a nonlinear quantum oscillator
We construct exact solutions of a spectral problem involving the Schrodinger equation for a nonlinear, one-parameter oscillator potential. In contrast to a previous analysis of the problem (Carinena et al 2007 Ann. Phys. 322 434–59), where solutions were given through a Rodrigues-type formula, our approach leads to closed-form representations of the solutions in terms of special functions, not containing any derivative operators. We show normalizability and orthogonality of our solutions, as well as correct reduction of the problem to the harmonic oscillator model, if the parameter in the potential gets close to zero.
119125621
Moduli vacuum bubbles produced by evaporating black holes
We consider a model with a toroidally compactified extra dimension giving rise to a temperature-dependent 4D effective potential with one-loop contributions due to the Casimir effect, along with a 5D cosmological constant. The forms of the effective potential at low and high temperatures indicate a possibility for the formation of a domain wall bubble, formed by the modulus scalar field, surrounding an evaporating black hole. This is viewed as an example of a recently proposed black hole vacuum bubble arising from matter-sourced moduli fields in the vicinity of an evaporating black hole [D. Green, E. Silverstein, and D. Starr, Phys. Rev. D 74, 024004 (2006)]. The black hole bubble can be highly opaque to lower-energy particles and photons, and thereby entrap them within. For high-temperature black holes, there may also be a symmetry-breaking black hole bubble of false vacuum of the type previously conjectured by Moss [I. G. Moss, Phys. Rev. D 32, 1333 (1985)], tending to reflect low-energy particles from its wall. A double bubble composed of these two different types of bubble may form around the black hole, altering the hole's emission spectrum that reaches outside observers. Smaller mass black holes that have already evaporated away could have left vacuum bubbles behind that contribute to the dark matter.
29278740
Domain defects in strings and walls.
A type of model is considered where the Witten mechanism allows the breaking of a discrete symmetry within the core of a cosmic string or a domain wall. The formation of a real scalar field condensate results in the creation of different, but energetically degenerate, domains which are separated by massive domain defects. The defects within strings (domain kinks) are particlelike states, whereas the defects within walls (domain ribbons) resemble stringlike states. Relativistic kink-antikink pairs annihilate after their initial formation, with the release of boson radiation, and kink-antikink pairs can be created through string intercommutations. Ribbons and antiribbons can be either infinite in extent or form closed loops. Ribbon loops can be involved in fission or fusion processes producing boson radiation, and oscillating ribbon loops decay mainly through the production of boson radiation, with a negligible fraction of the released energy being emitted in the form of gravitational radiation.
120292912
Gravitational field of a superconducting global string
SummaryThe Newtonian gravitational field of a superconducting global cosmic string is investigated using the weak-field approximation, and is found to receive contributions from the global string field, the condensate field, and the electromagnetic fields. For certain parameter ranges the gravitational field in the region exterior to the string may be everywhere repulsive, everywhere attractive, or repulsive in some regions and attractive in others. For a neutral superconducting global string there can exist a particular current for which the gravitational field of the superconducting global string approximately coincides with that of a Grand Unified Theory (GUT) scale Weyl string, and, as pointed out by Widom, Srivastava, and Redington, observed asymptotic galactic rotation velocities can be roughly explained without the introduction of any further dark-matter hypothesis.
8897328
Supersymmetry breaking and Fermi balls.
A simple model is presented where the disappearance of domain walls and the associated production of {open_quote}{open_quote}Fermi balls,{close_quote}{close_quote} which have been proposed as candidates for cold dark matter, are features which arise rather naturally in response to softly broken supersymmetry. {copyright} {ital 1996 The American Physical Society.}
120927641
A parameterization forSO(3) Yang-Mills-Higgs systems
SummaryA model consisting of anSO(3) gauge field interacting with an isovector Higgs field is investigated. The gauge fields and field tensors are parameterized by the Higgs field directionality and a gauge field structure function in terms of which the magnetic field and magnetic charge density of a 't Hooft-Polyakov magnetic monopole can be simply expressed. An isovector Debye potential for a 't Hooft-Polyakov gauge field is written in terms of the gauge field structure function.
18645695
The recent operational performance of the CERN omega ring imaging cerenkov detector
We discuss the design and construction of the Time Projection chambers (TPCs) of the Omega Ring Imaging Cerenkov Detector (RICH). Details are given of the TPC high voltage system and its monitoring and control. In addition, the operation and monitoring of the readout is described together with results of tests on the performance of the front end amplifiers. The operation of the RICH TPCs and electronics during the first data run of WA69, in 1984, is discussed together with relevant results from laboratory tests. Results from the preliminary analysis of a sample of data from the 1984 run are also presented.
110048496
The H1 Forward Track Detector at HERA II
In order to maintain efficient tracking in the forward region of H1 after the luminosity upgrade of the HERA machine, the H1 Forward Track Detector was also upgraded. While much of the original software and techniques used for the HERA I phase could be reused, the software for pattern recognition was completely rewritten. This, along with several other improvements in hit finding and high-level track reconstruction, are described in detail together with a summary of the performance of the detector.
24058982
The Omega Spectrometer Ring Imaging Cerenkov Detector Recent Detector Modifications and Event Analysis
A Ring Imaging Cerenkov (RICH) detector has now been successfully operated throughout a high-energy (70-200 GeV/c) photoproduction experiment at the CERN Omega Spectrometer. Recently complementary data using a hadron beam was taken with the same equipment. In each case about 20 million interactions were recorded. We discuss here features of the RICH device not yet described in previous publications and indicate by means of examples the way in which the RICH information is being used in the context of the overall experimental data analysis.
120611016
Nuclear photoproduction of rho mesons
Abstract Targets of Be, C, Al, Cu, Ag and Au were exposed to a tagged photon beam in the 2.75 to 4.35 GeV energy range and cross sections are presented for the reaction γA → Aϱ0. Optical spark chambers were used to examine charged particles and γ rays from the targets, so that the data are believed to be free from inelastic contamination. The results are analysed both in terms of total cross sections σ(Aγ → ϱA), and in terms of forward differential cross sections ( d σ d t ) θ=0 (γ A → ϱ A ) . From the A dependence of these cross sections we determine the total rho-nucleon cross section, σϱN, to be (22.5 ± 2.7) mb, and the absolute values of the cross sections determine the forward photoproduction cross section from a nucleon ( d σ d t ) θ=0 (γ p → ϱ p ) = (72.7 ± 8) μ b/GeV 2 . These values correspond to an assumed value αϱN = −0.2 for the ratio of the real to imaginary part of the ϱ nucleon forward scattering amplitude. The corresponding value of the photon-rho coupling constant γ ϱ 2 4π =0.65±0.16 .
121816869
Associated photoproduction of a charmed meson and a charmed baryon