26,036 research outputs found
Addendum to Technical Proposal: A Facility to Search for Hidden Particles (SHiP) at the CERN SPS
No full textWith the Technical Proposal submitted to the SPSC committee in April 2015, the SHiP collaboration declared its interest in proceeding towards a Comprehensive Design Study phase with the aim of preparing for the Technical Design Reports pending an approval by the CERN committees. Following the recommendation by the SPSC, it has been decided to complement the TP with this addendum that provides an update of the key aspects for the review of the SHiP project
Ship-owners' decisions to outsource vessel management
No full textShipping companies frequently outsource the management of their vessels. In this paper, we use data from Lloyd's Register Fairplay (2009) on 45,456 vessels belonging to 9,580 different shipowners to investigate the extent of outsourcing in shipping and to identify key factors affecting the likelihood of outsourcing. The results of our econometric analysis indicate that ship-owners' decisions to outsource are explained by the characteristics of the vessels in question (age, type, size) and the characteristics of the ship-owner (country of domiciliation, number of vessels). In addition, a specific country effect is identified for Greek ship-owners, which is in line with the findings of previous studies.
Outsourcing ship management: Implications for the logistics chain
No full textThe purpose of this paper is to contribute to a better understanding of the probability that shipping companies outsource the management of vessels to ship management companies, a decision with many implications for the logistics chain. Data on 39,925 vessels are used to investigate to the extent to which 4,049 different ship-owners (each operating a fleet of at least two vessels) outsource to ship-management service providers. We rely on multinomial Logit random and fixed effects regressions to explain how the characteristics of the owners and vessels influence this decision. We find that the size of the firm in terms of the number of vessels and the number of different types of vessels influence the likelihood of outsourcing. Also, ship-owners frequently implement a mixed strategy and outsource only some of their vessels.
The SHiP experiment at the proposed CERN SPS Beam Dump Facility
No full textThe Search for Hidden Particles (SHiP) Collaboration has proposed a
general-purpose experimental facility operating in beam-dump mode at the CERN
SPS accelerator to search for light, feebly interacting particles. The SHiP
experiment incorporates two complementary detectors. The upstream detector is
designed for recoil signatures of light dark matter (LDM) scattering and for
neutrino physics, in particular with tau neutrinos. It consists of a
spectrometer magnet housing a layered detector system with high-density
LDM/neutrino target plates, emulsion-film technology and electronic
high-precision tracking. The downstream detector system aims at measuring
visible decays of feebly interacting particles to both fully reconstructed
final states and to partially reconstructed final states with neutrinos, in a
nearly background-free environment. The detector consists of a 50\m long decay
volume under vacuum followed by a spectrometer and particle identification
system with a rectangular acceptance of 5\,m in width and 10\,m in height.
Using the high-intensity beam of 400\gev protons, the experiment aims at
profiting from the protons per year that are currently
unexploited at the SPS, over a period of 5--10 years. This allows probing dark
photons, dark scalars and pseudo-scalars, and heavy neutral leptons with
GeV-scale masses at sensitivities that largely exceed those of existing and
projected experiments. The sensitivity to light dark matter reaches well below
the dark matter relic density limits in the range from a few \mevcc up to
100\,MeV-scale masses, and it will be possible to study tau neutrino
interactions with unprecedented statistics. This paper describes the SHiP
experiment baseline setup and the detector systems, together with performance
results from prototypes in test beams, as it was prepared for the 2020 Update
of the European Strategy for Particle Physics
Sensitivity of the SHiP experiment to light dark matter
No full textDark matter is a well-established theoretical addition to the Standard Model supported by many observations in modern astrophysics and cosmology. In this context, the existence of weakly interacting massive particles represents an appealing solution to the observed thermal relic in the Universe. Indeed, a large experimental campaign is ongoing for the detection of such particles in the sub-GeV mass range. Adopting the benchmark scenario for light dark matter particles produced in the decay of a dark photon, with α = 0.1 and m = 3m, we study the potential of the SHiP experiment to detect such elusive particles through its Scattering and Neutrino detector (SND). In its 5-years run, corresponding to 2 · 10 protons on target from the CERN SPS, we find that SHiP will improve the current limits in the mass range for the dark matter from about 1 MeV to 300 MeV. In particular, we show that SHiP will probe the thermal target for Majorana candidates in most of this mass window and even reach the Pseudo-Dirac thermal relic.</p
Sensitivity of the SHiP experiment to dark photons decaying to a pair of charged particles
No full textDark photons are hypothetical massive vector particles that could mix with ordinary photons. The simplest theoretical model is fully characterised by only two parameters: the mass of the dark photon m and its mixing parameter with the photon, . The sensitivity of the SHiP detector is reviewed for dark photons in the mass range between 0.002 and 10 GeV. Different production mechanisms are simulated, with the dark photons decaying to pairs of visible fermions, including both leptons and quarks. Exclusion contours are presented and compared with those of past experiments. The SHiP detector is expected to have a unique sensitivity for m ranging between 0.8 and 3.3 GeV, and ranging between and
The Structure of Scientific Collaboration Networks in Scientometrics
No full textThe structure of scientific collaboration networks in scientometrics was investigated at the level of individuals by using bibliographic data of all papers published in the international journal Scientometrics retrieved from the Science Citation Index (SCI) during 1978 to 2004. Combined analysis of social network analysis (SNA), co-occurrence analysis, cluster analysis and frequency analysis of words was explored to reveal: (1) The microstructure of the collaboration network on scientists’ aspects of scientometrics; (2) The major collaborative fields of the collaborative sub-networks; (3) The collaborative center of the collaboration network in scientometrics
Genetic programming for the automatic design of controllers for a surface ship
No full textIn this paper, the implementation of genetic programming (GP) to design a contoller structure is assessed. GP is used to evolve control strategies that, given the current and desired state of the propulsion and heading dynamics of a supply ship as inputs, generate the command forces required to maneuver the ship. The controllers created using GP are evaluated through computer simulations and real maneuverability tests in a laboratory water basin facility. The robustness of each controller is analyzed through the simulation of environmental disturbances. In addition, GP runs in the presence of disturbances are carried out so that the different controllers obtained can be compared. The particular vessel used in this paper is a scale model of a supply ship called CyberShip II. The results obtained illustrate the benefits of using GP for the automatic design of propulsion and navigation controllers for surface ships
Sensitivity of the SHiP experiment to dark photons decaying to a pair of charged particles
No full textDark photons are hypothetical massive vector particles that could mix with ordinary photons. The simplest theoretical model is fully characterised by only two parameters: the mass of the dark photon m(gamma)D and its mixing parameter with the photon, epsilon. The sensitivity of the SHiP detector is reviewed for dark photons in the mass range between 0.002 and 10 GeV. Different productionmechanisms are simulated, with the dark photons decaying to pairs of visible fermions, including both leptons and quarks. Exclusion contours are presented and compared with those of past experiments. The SHiP detector is expected to have a unique sensitivity for m. D ranging between 0.8 and 3.3(-0.5)(+0.2) GeV, and epsilon(2) ranging between 10(-11) and 10(-17).LPHELPPCLCVM
Reconstruction of 400 GeV/c proton interactions with the SHiP-charm project
No full textThe SHiP-charm project was proposed to measure the associated charm
production induced by 400 GeV/c protons in a thick target, including the
contribution from cascade production. An optimisation run was performed in July
2018 at CERN SPS using a hybrid setup. The high resolution of nuclear emulsions
acting as vertex detector was complemented by electronic detectors for
kinematic measurements and muon identification. Here we present first results
on the analysis of nuclear emulsions exposed in the 2018 run, which prove the
capability of reconstructing proton interaction vertices in a harsh
environment, where the signal is largely dominated by secondary particles
produced in hadronic and electromagnetic showers within the lead target
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