34,458 research outputs found
CLIC e+e- Linear Collider Studies
This document provides input from the CLIC e+e- linear collider studies to
the update process of the European Strategy for Particle Physics. It is
submitted on behalf of the CLIC/CTF3 collaboration and the CLIC physics and
detector study. It describes the exploration of fundamental questions in
particle physics at the energy frontier with a future TeV-scale e+e- linear
collider based on the Compact Linear Collider (CLIC) two-beam acceleration
technique. A high-luminosity high-energy e+e- collider allows for the
exploration of Standard Model physics, such as precise measurements of the
Higgs, top and gauge sectors, as well as for a multitude of searches for New
Physics, either through direct discovery or indirectly, via high-precision
observables. Given the current state of knowledge, following the observation of
a \sim125 GeV Higgs-like particle at the LHC, and pending further LHC results
at 8 TeV and 14 TeV, a linear e+e- collider built and operated in
centre-of-mass energy stages from a few-hundred GeV up to a few TeV will be an
ideal physics exploration tool, complementing the LHC. Two example scenarios
are presented for a CLIC accelerator built in three main stages of 500 GeV, 1.4
(1.5) TeV, and 3 TeV, together with the layout and performance of the
experiments and accompanied by cost estimates. The resulting CLIC physics
potential and measurement precisions are illustrated through detector
simulations under realistic beam conditions.Comment: Submitted to the European Strategy Preparatory Grou
Beam Cleaning and Collimation Systems
Collimation systems in particle accelerators are designed to dispose of
unavoidable losses safely and efficiently during beam operation. Different
roles are required for different types of accelerator. The present state of the
art in beam collimation is exemplified in high-intensity, high-energy
superconducting hadron colliders, like the CERN Large Hadron Collider (LHC),
where stored beam energies reach levels up to several orders of magnitude
higher than the tiny energies required to quench cold magnets. Collimation
systems are essential systems for the daily operation of these modern machines.
In this document, the design of a multistage collimation system is reviewed,
taking the LHC as an example case study. In this case, unprecedented cleaning
performance has been achieved, together with a system complexity comparable to
no other accelerator. Aspects related to collimator design and operational
challenges of large collimation systems are also addressed.Comment: 35 pages, contribution to the 2014 Joint International Accelerator
School: Beam Loss and Accelerator Protection, Newport Beach, CA, USA , 5-14
Nov 201
CLIC e+e- Linear Collider Studies - Input to the Snowmass process 2013
This paper addresses the issues in question for Energy Frontier Lepton and
Gamma Colliders by the Frontier Capabilities group of the Snowmass 2013 process
and is structured accordingly. It will be accompanied by a paper describing the
Detector and Physics studies for the CLIC project currently in preparation for
submission to the Energy Frontier group.Comment: Submitted to the Snowmass process 2013. arXiv admin note: substantial
text overlap with arXiv:1208.140
A facility to Search for Hidden Particles (SHiP) at the CERN SPS
A new general purpose fixed target facility is proposed at the CERN SPS
accelerator which is aimed at exploring the domain of hidden particles and make
measurements with tau neutrinos. Hidden particles are predicted by a large
number of models beyond the Standard Model. The high intensity of the SPS
400~GeV beam allows probing a wide variety of models containing light
long-lived exotic particles with masses below (10)~GeV/c,
including very weakly interacting low-energy SUSY states. The experimental
programme of the proposed facility is capable of being extended in the future,
e.g. to include direct searches for Dark Matter and Lepton Flavour Violation.Comment: Technical Proposa
High intensity neutrino oscillation facilities in Europe
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fréjus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of μ+ and μ− beams in a storage ring. The far detector in this case is a 100 kt magnetized iron neutrino detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular He6 and Ne18, also stored in a ring. The far detector is also the MEMPHYS detector in the Fréjus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the physics reach of each facility, in particular for the measurement of CP violation in the lepton sector, and estimated the cost of construction. These have demonstrated that the best facility to build is the Neutrino Factory. However, if a powerful proton driver is constructed for another purpose or if the MEMPHYS detector is built for astroparticle physics, the Super Beam also becomes very attractive
From Exploration to Sensemaking: an Interactive Exploratory Search System
exist to satisfy people's information needs. Many search systems have been designed for well-formed and explicit information needs but few for exploratory purposes. By exploration, we mean the information need is ambiguous initially and evolves during the search process.
There are mainly two parts within the thesis. In the first part, we will develop an interactive exploratory search system for the arXiv database, an open e-print archive for scientific articles. The part is mostly based on an initial study, in which a search engine, Scinet, based on an intent estimation model is proposed. With this search engine, users can direct their exploration by giving feedbacks to the estimated search intents, which are represented by relevant keywords. Intents are visualized and arranged into a radial layout where the radius measures relevance and the angle measures similarity. Users can drag a keyword closer to the center to indicate higher relevance or click on a keyword to assign full relevance and then the retrieved documents will be updated accordingly. Compared to the initial search system, a mind-map functionality is also added as a new feature. With this mind-map, users can temporarily store the keywords or titles that they find interesting. To verify the interactive exploratory ability, we have designed and conducted a small-scale experiment based on the arXiv dataset. Particularly, the keywords for arXiv articles are extracted by an automatic keyword extraction algorithm since most of the arXiv articles do not provide keywords by the authors.
For the second part, we investigate a potential novel functionality of the Scinet search system on a large database of scientific articles. The ability of the system to support information seeking was shown in previous publication. Here we propose that this system will also support sensemaking, namely, help users to make sense of the results. We suggest that this advantage arises because in Scinet, not only are intents estimated but also the relationships between them are indicated on the interface. In order to better support sensemaking, the new functionality is also added to the prototype system in the initial study. We believe that this search system will help people to better understand and interpret the search results
- …