The LHCb Upgrade

The LHCb experiment is designed to perform high-precision measurements of CP violation and search for New Physics using the enormous flux involving beauty and charm quarks produced at the LHC. The operation and the results obtained from the data collected in 2010 and 2011 demonstrate that the detector is robust and functioning very well. However, the limit of 1 fb^-1 of data per nominal year cannot be overcome without improving the detector. We therefore plan for an upgraded spectrometer by 2018 with a 40 MHz readout and a much more flexible software-based triggering system that will increase the data rate as well as the efficiency specially in the hadronic channels. Here we present the LHCb detector upgrade plans, based on the Letter of Intent and Framework Technical Design Report.Comment: Presentation at the DPF 2013 Meeting of the American Physical Society Division of Particles and Fields, Santa Cruz, California, August 13-17, 201

On the sharp stability of critical points of the Sobolev inequality

Given $n\geq 3$, consider the critical elliptic equation $\Delta u + u^{2^*-1}=0$ in $\mathbb R^n$ with $u > 0$. This equation corresponds to the Euler-Lagrange equation induced by the Sobolev embedding $H^1(\mathbb R^n)\hookrightarrow L^{2^*}(\mathbb R^n)$, and it is well-known that the solutions are uniquely characterized and are given by the so-called ``Talenti bubbles''. In addition, thanks to a fundamental result by Struwe, this statement is ``stable up to bubbling'': if $u:\mathbb R^n\to(0,\infty)$ almost solves $\Delta u + u^{2^*-1}=0$ then $u$ is (nonquantitatively) close in the $H^1(\mathbb R^n)$-norm to a sum of weakly-interacting Talenti bubbles. More precisely, if $\delta(u)$ denotes the $H^1(\mathbb R^n)$-distance of $u$ from the manifold of sums of Talenti bubbles, Struwe proved that $\delta(u)\to 0$ as $\lVert\Delta u + u^{2^*-1}\rVert_{H^{-1}}\to 0$. In this paper we investigate the validity of a sharp quantitative version of the stability for critical points: more precisely, we ask whether under a bound on the energy $\lVert\nabla u\rVert_{L^2}$ (that controls the number of bubbles) it holds $\delta(u) \lesssim \lVert\Delta u + u^{2^*-1}\rVert_{H^{-1}}$. A recent paper by the first author together with Ciraolo and Maggi shows that the above result is true if $u$ is close to only one bubble. Here we prove, to our surprise, that whenever there are at least two bubbles then the estimate above is true for $3\le n\le 5$ while it is false for $n\ge 6$. To our knowledge, this is the first situation where quantitative stability estimates depend so strikingly on the dimension of the space, changing completely behavior for some particular value of the dimension $n$.Comment: 42 page

A complete system for controlling and monitoring the timing of the LHCb experiment

The LHCb experiment at CERN will study the results of the production of B/antiB in the LHC accelerator mesons with the higher precision ever. It is vital that the experiment is able to record sub-detectors signals at the optimal detector efficiency, referring to the right collision occurring in the LHC ring, and that those signals are stable, clean and reliable. The solution is the development of a complete system to centrally time align and at the same time to monitor the timing of the whole experiment. An electronics custom-made acquisition board, called Beam Phase and Intensity Monitor (BPIM), has the main aim to monitor the beam processing a bipolar signal coming from a dedicated Beam Pick-Up detector, sitting along the LHC ring and whose signal is a clear representation of the bunches of protons. The BPIM is then able to integrate the intensity of the beam and at the same time to compare the phase of the bunch signal with the clock coming from the timing distribution system as well as the phase of the orbit signal with the signal generated from the first beam bunch. The principal applications of the BPIM are to determine the position of the orbit signal locally, to monitor bunch-by-bunch the clock phase with respect to the bunch passing through the detector, to have a clear structure of the beam injected, to determine the exact trigger conditions for sampling events in the detector, to determine the exact trigger conditions for significative events of not, checking whether the detector samples a bunch with protons (or lead ions) or an empty bunch, to produce an empty crossing veto for the sampled events whenever a bunch is absent in the expected location, to have a relative measure of the intensities of bunch, to have instantaneaous information about the presence/absence of beam, and, not less important, to search for ghost bunches. The board is paired with the RF2TTC system developed by the LHC group and whose aim is to control, clean, convert and transmit the bunch clock (~40 MHz) and the orbit clock (~11 KHz) to the the whole experiment. A complete user-friendly interface system, developed using the SCADA software PVSS II with the Distributed Information Management (DIM) system as communication protocol, allows to control and monitor real-time the available information

A new readout control system for the LHCb upgrade at CERN

The LHCb experiment has proposed an upgrade towards a full 40 MHz readout system in order to run between five and ten times its initial design luminosity. The entire readout architecture will be upgraded in order to cope with higher sub-detector occupancies, higher rate and higher network load. In this paper, we describe the architecture, functionalities and a first hardware implementation of a new fast Readout Control system for the LHCb upgrade, which will be entirely based on FPGAs and bi-directional links. We also outline the real-time implementations of the new Readout Control system, together with solutions on how to handle the synchronous distribution of timing and synchronous information to the complex upgraded LHCb readout architecture. One section will also be dedicated to the control and usage of the newly developed CERN GBT chipset to transmit fast and slow control commands to the upgraded LHCb Front-End electronics. At the end, we outline the plans for the deployment of the system in the global LHCb upgrade readout architecture

Theoretically Expressive and Edge-aware Graph Learning

We propose a new Graph Neural Network that combines recent advancements in the field. We give theoretical contributions by proving that the model is strictly more general than the Graph Isomorphism Network and the Gated Graph Neural Network, as it can approximate the same functions and deal with arbitrary edge values. Then, we show how a single node information can flow through the graph unchanged

Adoption of additive manufacturing technology: drivers, barriers and impacts on upstream supply chain design

Purpose – This paper investigates how the adoption of additive manufacturing (AM) impacts upstream supply chain (SC) design and considers the influence of drivers and barriers towards the adoption. Design/methodology/approach – Ten case studies investigating AM adoption by Original Equipment Manufacturers (OEMs) in five industries were conducted. This research is driven by a literature-based framework, and the results are discussed according to the theory of transaction cost economics (TCE). Findings – The case studies reveal four patterns of AM adoption that affect upstream SC design (due to changes in supply base or types of buyer–supplier relationships): make, buy, make and buy and vertical integration. A make or buy decision is based on the level of experience with the technology, on the AM application (rapid manufacturing, prototyping or tooling) and on the need of control over production. Other barriers playing a role in the decision are the high initial investments and the lack of skills and knowledge. Originality/value – This paper shows how different decisions regarding AM adoption result in different SC designs, with a specific focus on the upstream SC and changes in the supply base. This research is among the first to provide empirical evidence on the impact of AM adoption on upstream SCs and to identify drivers of the make or buy decision when adopting AM through the theoretical lens of TC

Posture Recognition Using the Interdistances Between Wearable Devices

Recognition of user's postures and activities is particularly important, as it allows applications to customize their operations according to the current situation. The vast majority of available solutions are based on wearable devices equipped with accelerometers and gyroscopes. In this article, a different approach is explored: The posture of the user is inferred from the interdistances between the set of devices worn by the user. Interdistances are first measured by using ultra-wideband transceivers operating in two-way ranging mode and then provided as input to a classifier that estimates current posture. An experimental evaluation shows that the proposed method is effective (up to ∼98.2% accuracy), especially when using a personalized model. The method could be used to enhance the accuracy of activity recognition systems based on inertial sensors