Brief Announcement: A Tight Lower Bound for Clock Synchronization in Odd-Ary M-Toroids

In this paper we show a tight closed-form expression for the optimal clock synchronization in k-ary m-cubes with wraparound, where k is odd. This is done by proving a lower bound of 1/4um (k-1/k), where k is the (odd) number of processes in each of the m dimensions, and u is the uncertainty in delay on every link. Our lower bound matches the previously known upper bound

Exploiting the ATLAS detector in a search for stop squark in a compressed mass spectrum using the Higgs boson

In past decades, experimental and theoretical efforts offered several reasons to believe that the Standard Model of particles (SM) is nothing more than an effective low-energy approximation of a more fundamental theory. The theory of Supersymmetry (SUSY) seems to be a natural candidate to extend the SM. Of particular interest among SUSY particles is the stop squark, due to the fact that it gives the dominant contribution to the Higgs boson mass radiative corrections. In this thesis, I present a search for direct stop squark pair production in data collected by the ATLAS detector at the CERN Large Hadron Collider (LHC) during 2015-16 in proton-proton collisions with a centre-of mass energy of 13 TeV. This search takes advantage of the full capabilities of ATLAS further increased by the improvements made to the ATLAS pixel detector during 2014 - 2015. Both the installation of a new pixel detector layer (Insertable B-Layer) and the upgrade of the data-acquisition system of the pre-existing layers are presented in detail in this thesis, along with their impact to the b-jets reconstruction effciency. This search for stop squark relies on events with a pair of b-jets compatible with the decay of an Higgs boson to select the signal candidate events. Results of this selection are interpreted in models with long decay chains involving a heavy neutralino or the heavier stop squark. No excess is observed in the data with respect to the SM predictions for any of the models and decay chains, thus excluding at 95% confidence level stop2 and stop1 masses up to about 800 GeV and extending the exclusion region of supersymmetric parameter space covered by previous LHC searches

Measurement of the ZH(H -> bb) associated production with Z l+l- in pp collisions at square root of s = 13 TeV with the ATLAS Experiment

The signal strength measurement of the pp$\rightarrow$VH(H \rightarrow bb) at a center of mass energy of pp collision of 13 TeV is presented in this thesis. The data have been collected with the ATLAS detector in 2015, 2016 and 2017 data taking corresponding to an integrated luminosity of 79.8 fb-1. The analysis has been performed in three different channels distinguished according to the number of charged leptons in the final state coming from the leptonical decay of the associated vector boson. The measured signal strength, with respect to the Standard Model expectation, is $\mu_VH(H$\rightarrow bb$)=1.08+0.27-0.31 (from the combination of three analysis channels) with an observed significance with the background-only hypothesis, of 4.9$\sigma$, with respect to an expected value of 4.3. The iteration of the analysis with the full Run2 statistics (139 fb-1) is also treated, with particular attention to the main innovations introduced with respect to the previous analyisis. A description of a phenomenological study of the total proton-proton cross section and$\rho-parameter (defined as the ratio of the real to imaginary part of the elastic scattering amplitude in the forward direction) is also presented. LUCID-2 is the reference detector for online and offline luminosity measurements for ATLAS. It is described with particular attention to the PMT gain monitoring system where I developed a code for the analysis of the calibration data.Il tema principale di questa tesi è la misura della \emph{signal strength} del canale di produzione associata dell'Higgs con un bosone vettore pp \rightarrow VH(H\rightarrow b\bar{b})$, con l'Higgs che decade in due quark$b$, ad un'energia nel centro di massa di 13 TeV. I dati sono stati raccolti con l'esperimento ATLAS nel 2015, 2016 e 2017, per una luminosità integrata di 79.8 fb$^{-1}. L'analisi è stata effettuata in tre diversi canali, distinti tra loro in base al numero di leptoni carichi nello stato finale, derivanti dal decadimento leptonico del bosone vettore associato. La \emph{signal strength} misurata dalla combinazione dei tre canali è \mu_{VH(H\rightarrow b\bar{b})}$=1.08$^{+0.27}_{-0.31}$, con un significanza di 4.9$\sigma$, rispetto ad un valore atteso di 4.3. Viene trattata anche l'iterazione dell'analisi con l'intera statistica del Run2 di LHC (139 fb$^{-1}), sottolineando i principali cambiamenti rispetto alla strategia precedentemente adottata.\\ E' fornita una descrizione del LUCID-2, il rivelatore di riferimento per le misure \emph{online} e \emph{offline} di luminosità, con particolare attenzione al sistema di monitoraggio del guadagno dei fotomoltiplicatori, per cui mi sono occupata dell'analisi dei dati di calibrazione raccolti. E' inoltre presentata una descrizione dei miei studi fenomenologici sull'evoluzione della sezione d'urto totale adronica e del parametro \rho$ (definito come il rapporto tra la parte reale e immaginaria dell'ampiezza di scattering elastico nella direzione \emph{forward})

Topical Workshop on Electronics for Particle Physics

The purpose of the workshop was to present results and original concepts for electronics research and development relevant to particle physics experiments as well as accelerator and beam instrumentation at future facilities; to review the status of electronics for the LHC experiments; to identify and encourage common efforts for the development of electronics; and to promote information exchange and collaboration in the relevant engineering and physics communities

NASA Tech Briefs Index, 1976

Abstracts of new technology derived from the research and development activities of the National Aeronautics and Space Administration are presented. Emphasis is placed on information considered likely to be transferrable across industrial, regional, or disciplinary lines. Subject matter covered includes: electronic components and circuits; electronic systems; physical sciences; materials; life sciences; mechanics; machinery; fabrication technology; and mathematics and information sciences

VLF experiment equipment for Applications Technology Satellite-2 /ATS-2/ Final report

Equipment for ATS 2 VLF and particle experiments, with ATS 1 particle detection experiment instrumentatio

A superconducting bandpass delta-sigma modulator for direct analog-to-digital conversion of microwave radio

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 291-305).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Direct analog-to-digital conversion of multi-GHz radio frequency (RF) signals is the ultimate goal in software radio receiver design but remains a daunting challenge for any technology. This thesis examines the potential of superconducting technology for realizing RF analog-to-digital converters (ADCs) with improved performance. A bandpass delta-sigma (AE) modulator is an attractive architecture for digitizing narrowband signals with high linearity and a large signal-to-noise ratio (SNR). The design of a superconducting bandpass AE modulator presented here exploits several advantages of superconducting electronics: the high quality factor of resonators, the high sampling rates of comparators realized with Josephson junctions, natural quantization of voltage pulses, and high circuit sensitivity. Demonstration of a superconducting circuit operating at clock rates in the tens of GHz is often hindered by the difficulty of high speed interfacing with room-temperature test equipment. In this work, a test chip with integrated acquisition memory is used to simplify high speed testing in a cryogenic environment. The small size (256 bits) of the on-chip memory severely limits the frequency resolution of spectra based on standard fast Fourier transforms. Higher resolution spectra are obtained by "segmented correlation", a new method for testing ADCs. Two different techniques have been found for clocking the superconducting modulator at frequencies in the tens of GHz. In the first approach, an optical clocking technique was developed, in which picosecond laser pulses are delivered via optical fiber to an on-chip metal-semiconductor-metal (MSM) photodiode, whose output current pulses trigger the Josephson circuitry. In the second approach, the superconducting modulator is clocked by an on-chip Josephson oscillator.(cont.) These testing methods have been applied in the successful demonstration of a super-conducting bandpass AE modulator fabricated in a niobium integrated circuit process with 1 kA/cm2 critical current density for the Josephson junctions. At a 42.6 GHz sampling rate, the center frequency of the experimental modulator is 2.23 GHz, the measured SNR is 49 dB over a 20.8 MHz bandwidth, and a full-scale (FS) input is -17.4 dBm. At a 40.2 GHz sampling rate, the measured in-band noise is -57 dBFS over a 19.6 MHz bandwidth.by John Francis Bulzacchelli.Ph.D

NASA Tech Briefs, Fall 1979

Topics include: NASA TU Services: Technology Utilization services that can assist you in learning about and applying NASA technology; New Product Ideas: A summary of selected innovations of value to manufacturers for the development of new products; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Life Sciences; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences

Cumulative index to NASA Tech Briefs, 1986-1990, volumes 10-14

Tech Briefs are short announcements of new technology derived from the R&D activities of the National Aeronautics and Space Administration. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This cumulative index of Tech Briefs contains abstracts and four indexes (subject, personal author, originating center, and Tech Brief number) and covers the period 1986 to 1990. The abstract section is organized by the following subject categories: electronic components and circuits, electronic systems, physical sciences, materials, computer programs, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences