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.
119182001
A Modified Theory of Gravity with Torsion and Its Applications to Cosmology and Particle Physics
In this paper we consider the most general least-order derivative theory of gravity in which not only curvature but also torsion is explicitly present in the Lagrangian, and where all independent fields have their own coupling constant: we will apply this theory to the case of ELKO fields, which is the acronym of the German Eigenspinoren des LadungsKonjugationsOperators designating eigenspinors of the charge conjugation operator, and thus they are a Majorana-like special type of spinors; and to the Dirac fields, the most general type of spinors. We shall see that because torsion has a coupling constant that is still undetermined, the ELKO and Dirac field equations are endowed with self-interactions whose coupling constant is undetermined: we discuss different applications according to the value of the coupling constants and the different properties that consequently follow. We highlight that in this approach, the ELKO and Dirac field’s self-interactions depend on the coupling constant as a parameter that may even make these non-linearities manifest at subatomic scales.
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.
119165266
The most general ELKO matter in torsional f(R)‐theories
We study f(R)-gravity with torsion in presence of the most general ELKO matter, checking the consistency of the conservation laws with the matter field equations; we discuss some mathematical features of the field equations in connection with a cosmological application.
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.
119158982
LEPTONIC ELECTROWEAK SPIN-TORSION INTERACTIONS
In this paper we consider the most general field equations for a system of two fermions of which one single-handed, showing that the spin-torsion interactions among these spinors have a structure identical to that of the electroweak forces among leptons; possible extensions are discussed.
111127502
The front-end chip of the SuperB SVT detector
Abstract The asymmetric e + e − collider SuperB is designed to deliver a high luminosity, greater than 10 36 cm − 2 s − 1 , with moderate beam currents and a reduced center of mass boost with respect to earlier B-Factories. The innermost detector is the Silicon Vertex Tracker which is made of 5 layers of double sided silicon strip sensors plus a layer 0, that can be equipped with short striplets detectors in a first phase of the experiment. In order to achieve an overall track reconstruction efficiency above 98% it is crucial to optimize both analog and digital readout circuits. The readout architecture being developed for the front-end chips will be able to cope with the very high rates expected in the first layer. The digital readout will be optimized to be fully efficient for hit rates up to 2 MHz/strip, including large margins on the maximum expected background rates, but can potentially accommodate higher rates with a proper tuning of the buffer depth. The readout is based on a triggered architecture where each of the 128 strip channel is provided with a dedicated digital buffer. Each buffer collects the digitized charge information by means of a 4-bit TOT, storing it in conjunction with the related time stamp. The depth of buffers was dimensioned considering the expected trigger latency and hit rate including suitable safety margins. Every buffer is connected to a highly parallelized circuit handling the trigger logic, rejecting expired data in the buffers and channeling the parallel stream of triggered hits to the common output of the chip. The presented architecture has been modeled by HDL language and investigated with a Monte Carlo hit generator emulating the analog front-end behavior. The simulations showed that even applying the highest stressing conditions, about 2 MHz per strip, the efficiency of the digital readout remained above 99.8%.
109176666
The data acquisition system of the SuperB-SVT beam test
Abstract Prototypes of a new hybrid pixel detector and a high resistivity detector with short strips, developed by the VIPIX Collaboration and aimed at equipping the layer-0 of the SuperB vertex detector, have been tested in September 2011 with a 120 GeV pion beam at the SPS H6 beam line at CERN. They are placed at the center of a reference telescope consisting of six planes of silicon detector with a double-sided strip readout. Both the telescope and the detectors under test (DUT) are equipped with a custom-design, data-push digital readout. The main elements of the trigger and data acquisition system are two VME boards (EDRO) organized in a master-slave configuration and responsible for programming the front-end chips of both the telescope and the DUT. The master board distributes a global synchronization clock and the triggers to all devices, including two 3×3 analog-maps matrices placed behind the DUT and supplied with an independent readout. Both EDROs act as event-fragment builders. These are sent out to a remote PC for event building, buffering and storage.
54028581
Recent developments on CMOS MAPS for the SuperB Silicon Vertex Tracker
Abstract In the design of the Silicon Vertex Tracker for the high luminosity SuperB collider, very challenging requirements are set by physics and background conditions on its innermost Layer0: small radius (about 1.5 cm), resolution of 10 – 15 μ m in both coordinates, low material budget 1 % X 0 , and the ability to withstand a background hit rate of several tens of MHz / cm 2 . Thanks to an intense R&D program the development of Deep NWell CMOS MAPS (with the ST Microelectronics 130 nm process) has reached a good level of maturity and allowed for the first time the implementation of thin CMOS sensors with similar functionalities as in hybrid pixels, such as pixel-level sparsification and fast time stamping. Further MAPS performance improvements are currently under investigation with two different approaches: the INMAPS CMOS process, featuring a quadruple well and a high resistivity substrate, and 3D CMOS MAPS, realized with vertical integration technology. In both cases specific features of the processes chosen can improve charge collection efficiency, with respect to a standard DNW MAPS design, and allow to implement a more complex in-pixel logic in order to develop a faster readout architecture. Prototypes of MAPS matrix, suitable for application in the SuperB Layer0, have been realized with the INMAPS 180 nm process and the 130 nm Chartered/Tezzaron 3D process and results of their characterization will be presented in this paper.
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.
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.