118565299
Short note on the stabilty of a dilatonic wall
A nontopological soliton solution of dilaton–Maxwell theory describes a domain wall-like solution which confines magnetic flux in its core (Gibbons and Wells, Class Quant Grav 11:2499, 1994). Since the solution is not stabilized by a nontrivial topology of the vacuum manifold, it is interesting to see if the static solution is stable against small fluctuations. We consider the stability of the solution in response to small fluctuations in the scalar and magnetic fields. It is determined that the ansatz solution does indeed exhibits stability.
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.}
119203809
Chameleon gravity and satellite geodesy
We consider the possibility of the detection of a chameleon effect by an earth orbiting satellite such as LAGEOS, and possible constraints that might be placed on chameleon model parameters. Approximate constraints presented here result from using a simple monopole approximation for the gravitational field of the earth, along with results from the Khoury-Weltman chameleon model, solar system constraints obtained from the Cassini mission, and parameter bounds obtained from the LAGEOS satellite. It is furthermore suggested that a comparison of ground-based and space-based multipole moments of the geopotential could reveal a possible chameleon effect.
124764978
Brans-Dicke theory and the Pioneer anomaly
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.
121816869
Associated photoproduction of a charmed meson and a charmed baryon
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.
38275310
Time-dependent propagation of high-energy laser beams through the atmosphere: II
Various factors that can effect thermal blooming in stagnation zone situations are examined, including stagnation-zone motion, longitudinal air motion in the neighborhood of the stagnation zone, and the effects of scenario noncoplanarity. Of these effects, only the last offers reasonable hope of reducing the strong thermal blooming that normally accompanies stagnation zones; in particular, noncoplanarity should benefit multipulse more than cw beams. The methods of treating nonhorizontal winds hydrodynamically for cw and multipulse steady-state sources are discussed. Aspects of pulse “self-blooming” are also considered.
22405819
A search for narrow resonances in proton-proton collisions at 53 GeV centre-of-mass energy
Abstract A search for narrow resonances produced in pp collisions at the CERN ISR has been carried out using two magnetic spectrometers to measure and identify two-final-state charged hadrons. The resultant two-particle invariant mass spectra show no strong structure suggesting any new narrow resonance. The statistical significance of various enhancements seen in the data is discussed, and upper limits on the cross section times branching ratio for new particle production are presented.
17884247
Performance of the LHCb RICH detector at the LHC
The LHCb experiment has been taking data at the Large Hadron Collider (LHC) at CERN since the end of 2009. One of its key detector components is the Ring-Imaging Cherenkov (RICH) system. This provides charged particle identification over a wide momentum range, from 2–100 GeV/c. The operation and control, software, and online monitoring of the RICH system are described. The particle identification performance is presented, as measured using data from the LHC. Excellent separation of hadronic particle types (π, K, p) is achieved.