4,036 research outputs found
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 , consider the critical elliptic equation in with . This equation corresponds to the
Euler-Lagrange equation induced by the Sobolev embedding , 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 almost
solves then is (nonquantitatively) close in the
-norm to a sum of weakly-interacting Talenti bubbles. More
precisely, if denotes the -distance of from
the manifold of sums of Talenti bubbles, Struwe proved that as
.
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 (that controls the number of
bubbles) it holds .
A recent paper by the first author together with Ciraolo and Maggi shows that
the above result is true if 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 while it is false for . 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 .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
Intergroup Contact Is Associated with Less Negative Attitude toward Women Managers: The Bolstering Effect of Social Dominance Orientation
This cross-sectional study examined the intergroup contact hypothesis in the workplace by enrolling 150 Italian employees. Within the framework of social dominance theory, the purpose of this study was to test the assumption that individuals with higher levels of social dominance orientation are more likely to exhibit prejudice against women in managerial positions and benefit more from intergroup contact with a female supervisor. In particular, we found that individuals with higher levels of social dominance orientation exhibited more negative attitudes towards women in manager positions, but this effect only appeared when their superiors were women, as opposed to men. In addition, participants with higher social dominance orientation experienced more positive outcomes from intergroup contact, resulting in less negative attitudes toward women managers, than those with lower social dominance orientation. Overall, these findings yield insights into how intergroup contact affects individuals with prejudice tendencies, indicating that contact with the targeted group (i.e., women in managerial positions) is negatively associated with negative attitudes towards the group, even when the prejudice is driven by social dominance orientation. These results could shed light on new routes to design practical intervention aimed at solving prejudice towards women in leadership roles
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
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