56182755
TRACK FINDING AND FITTING IN THE H1 FORWARD TRACK DETECTOR
Abstract The tracking environment in the H1 Forward Track Detector, where the hit multiplicity from proton fragments is high, is particularly hostile. The techniques and software which have been developed for pattern recognition and Kalman fitting of charged particle tracks in this region are described in detail.
123844258
Diffractive Photoproduction of a $b_1 \pi$ System
121568291
Multiplicity distributions associated with charged hadron production over a range of transverse momentum and production angle at ISR energies
Abstract The charged multiplicity density M , associated with identified charged hadrons up to 3.0 GeV/ c in p T , is presented at ISR energies from 23.4 to 63.4 GeV and at 3 laboratory angles, as a function of pseudorapidity and azimuth.
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.
122240842
Multiplicities associated with the production of pions, kaons or protons of high transverse momentum, at the ISR
Abstract In high-energy proton-proton collisions, the mean charged multiplicity M in the central region, associated with a high-PT hadron trigger at 90°, shows a linear dependence on both ln s and PT. M is measured to depend on the type (π ± , K ± , p or p ) of the idenfied high-PT trigger particle.
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 .
119755784
Interactions Between Magnetically Charged Particles and Charged Superconducting Strings
119027742
Generalized dilaton-Maxwell cosmic string and wall solutions
Abstract The class of static solutions found by Gibbons and Wells for dilaton-electrodynamics in flat spacetime, which describe nontopological strings and walls that trap magnetic flux, is extended to a class of dynamical solutions supporting arbitrarily large, nondissipative traveling waves, using techniques previously applied to global and local topological defects. These solutions can then be used in conjunction with S-duality to obtain more general solitonic solutions for various axidilaton-Maxwell theories. As an example, a set of dynamical solutions is found for axion, dilaton, and Maxwell fields in low energy heterotic string theory using the SL ( 2 , R ) invariance of the equations of motion.
124068899
Structure equations for a monopole model with a coleman-weinberg potential
SummaryA model consisting of aSO3 gauge field interacting with an isovector Higgs field is investigated. When the Higgs mass parameter vanishes, no symmetry breakdown occurs at the tree level, but may be induced at the one-loop level. The one-loop effective potential is of the Coleman-Weinberg type, which is required of many new inflationary cosmological scenarios. Approximate equations determining the structure of a magnetic monopole are obtained at the one-loop level of this model.RiassuntoSi studia un modello ehe consiste in un campo di gauge SO3 che interagisce con un campo di Higgs isovettoriale. Quando il parametro di massa di Higgs si annulla non si verifica una rottura di simmetria a livello di albero, ma tale rottura si può indurre a livello di un loop. Il Potenziale efficace ad un loop è del tipo di Coleman-Weinberg, cui sono richiesti molti nuovi scenari di espansione cosmologica. Si ottengono equazioni approssimate che determinano la struttura di un monopolo magnetico al livello di un loop di questo modello.
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.
119078909
Gauged dimension bubbles
Some of the peculiar electrodynamical effects associated with gauged ``dimension bubbles'' are presented. Such bubbles, which effectively enclose a region of 5d spacetime, can arise from a 5d theory with a compact extra dimension. Bubbles with thin domain walls can be stabilized against total collapse by the entrapment of light charged scalar bosons inside the bubble, extending the idea of a neutral dimension bubble to accommodate the case of a gauged U(1) symmetry. Using a dielectric approach to the 4d dilaton-Maxwell theory, it is seen that the bubble wall is almost totally opaque to photons, leading to a new stabilization mechanism due to trapped photons. Photon dominated bubbles very slowly shrink, resulting in a temperature increase inside the bubble. At some critical temperature, however, these bubbles explode, with a release of radiation.