119118411
The Einstein-Yang-Mills equations from Bianchi identities
We suggest a novel extension to the Kaluza–Klein scheme that allows us to obtain consistently all SU(n) Einstein–Yang–Mills theories. This construction is based on allowing the five-dimensional spacetime to carry some nonvanishing torsion; however, the four-dimensional spacetime remains intrinsically torsion-free.
118464233
Hadronic Electroweak Spin-Torsion Interactions
In a previous paper we considered matter field equations with torsional contribution giving rise to special interactions which have eventually been shown to have the same structure of the electroweak forces; the results obtained in that paper are extended in this paper to the whole first generation of fermions. As a possible outlook the extension to all generations is discussed and consequently some speculations about the value for the mass of the Higgs field are presented.
119153029
Metric-torsional conformal gravity
Abstract When in general geometric backgrounds the metric is accompanied by torsion, the metric conformal properties should correspondingly be followed by analogous torsional conformal properties; however a combined metric torsional conformal structure has never been found which provides a curvature that is both containing metric-torsional degree of freedom and conformally invariant: in this Letter we construct such a metric-torsional conformal curvature. We proceed by building the most general action, then deriving the most general system of field equations; we check their consistency by showing that both conservation laws and trace condition are verified. Final considerations and comments are outlined.
19031000
Taking Kaluza seriously leads to a non-gauge-invariant electromagnetic theory in a curved space-time
Kaluza's metric with the cylinder condition is considered without the weak gravitational field approximation. It is shown that these hypoteses lead to a non-gauge-invariant electromagnetic theory in a curved space-time. The problem of electro-gravitational unification is considered from this point of view.
119108946
Dirac spinors in Bianchi-I f(R)-cosmology with torsion
We study Dirac spinors in Bianchi type-I cosmological models, within the framework of torsional f(R)-gravity. We find four types of results: the resulting dynamic behavior of the universe depends on the particular choice of function f(R); some f(R) models do not isotropize and have no Einstein limit, so that they have no physical significance, whereas for other f(R) models isotropization and Einsteinization occur, and so they are physically acceptable, suggesting that phenomenological arguments may select f(R) models that are physically meaningful; the singularity problem can be avoided, due to the presence of torsion; the general conservation laws holding for f(R)-gravity with torsion ensure the preservation of the Hamiltonian constraint, so proving that the initial value problem is well-formulated for these models.
119264146
Causal propagation for ELKO fields
We shall consider the general problem of causal propagation for spinor fields, focus attention in particular on the case constituted by ELKO fields and will show that the problem of causal propagation for ELKO fields is always solvable.
120546156
A radiation tolerant phototube power supply for the electromagnetic calorimeter of the HERA-B experiment
Abstract The design of the phototube power supply for the HERA- B Electromagnetic Calorimeter is presented. A choice of the solution on the basis of the Cockcroft–Walton voltage multiplier is validated. Schematics developed are discussed. A special section describes the behaviour of the crucial components under irradiation since radiation tolerance becomes one of the most important items in the severe HERA- B radiation environment. Finally, performance achieved is presented.
120117699
Latest results of the R&D on CMOS MAPS for the Layer0 of the SuperB SVT
Physics and high background conditions set very challenging requirements on readout speed, material budget and resolution for the innermost layer of the SuperB Silicon Vertex Tracker operated at the full luminosity. Monolithic Active Pixel Sensors (MAPS) are very appealing in this application since the thin sensitive region allows grinding the substrate to tens of microns. Deep N-Well MAPS, developed in the ST 130 nm CMOS technology, achieved in-pixel sparsification and fast time stamping. Further improvements are being explored with an intense R&D program, including both vertical integration and 2D MAPS with the INMAPS quadruple well. We present the results of the characterization with IR laser, radioactive sources and beam of several chips produced with the 3D (Chartered/Tezzaron) process. We have also studied prototypes exploiting the features of the quadruple well and the high resistivity epitaxial layer of the INMAPS 180 nm process. Promising results from an irradiation campaign with neutrons on small matrices and other test-structures, as well as the response of the sensors to high energy charged tracks are presented.
16866620
Analysis of charmonium production at fixed-target experiments in the NRQCD approach
We present an analysis of the existing data on charmonium hadro-production based on non-relativistic QCD (NRQCD) calculations at the next-to-leading order (NLO). All the data on J/psi and psi' production in fixed-target experiments and on pp collisions at low energy are included. We find that the amount of color octet contribution needed to describe the data is about 1/10 of that found at the Tevatron.
109274131
The EDRO Board Connected to the Associative Memory: a “Baby” FastTracKer Processor for the ATLAS Experiment
Abstract The FastTracKer (FTK), a hardware dedicated processor, performs fast and precise online full track reconstruction at the ATLAS experiment, within an average latency of few dozens of microseconds. Before production of the ﬁnal system for tracking in high-occupancy conditions with the best of available technology, we plan to use existing prototypes of the FTK hardware to exercise its functions in the ATLAS environment. We describe the “baby FTK”, consisting of a few hardware elements implementing the ﬁrst stages of the system, and discuss our plans to grow the system into a full-functionality FTK “vertical slice” covering a small projective wedge of the detector. We report on the performances and structure of the “baby FTK”, including the pixel/strip hit clustering (clustering mezzanine), hit organization and distribution (EDRO) and the Associative Memory pattern recognition function. We describe brieﬂy also the possible future evolution including the addition of the Track Fitter.
54175840
Beam test results for the SuperB-SVT thin striplet detector
The baseline detector option for the first layer of the SuperB Silicon Vertex Tracker (SVT) is a high resistivity double-sided silicon device with short strips (striplets) at 45° angle to the detector's edge. A prototype was tested with a 120 GeV/c pion beam in September 2011 at the SPS-H6 test-beam line at CERN. In this paper studies on efficiency, resolution and cluster size are reported.