25,384 research outputs found
Abstract knowledge in the broken-string problem : evidence from nonhuman primates and pre-schoolers
There was funding from the Royal Commission for the Exhibition of 1851.There is still large controversy about whether abstract knowledge of physical problems is uniquely human. We presented 9 capuchin monkeys, 6 bonobos, 6 chimpanzees and 48 children with two versions of a broken-string problem. In the standard condition, participants had to choose between an intact and a broken string as means to a reward. In the critical condition, the functional parts of the strings were covered up and replaced by perceptually similar, but non-functional cues. Apes, monkeys and young children performed significantly better in the standard condition in which the cues played a functional role, indicating knowledge of the functional properties involved. Moreover, a control experiment with chimpanzees and young children ruled out that this difference in performance could be accounted for by differences of perceptual feedback in the two conditions. We suggest that, similar to humans, nonhuman primates partly rely on abstract concepts in physical problem-solving.Peer reviewe
Particle identification
Particle IDentification (PID) is fundamental to particle physics experiments.
This paper reviews PID strategies and methods used by the large LHC
experiments, which provide outstanding examples of the state-of-the-art. The
first part focuses on the general design of these experiments with respect to
PID and the technologies used. Three PID techniques are discussed in more
detail: ionization measurements, time-of-flight measurements and Cherenkov
imaging. Four examples of the implementation of these techniques at the LHC are
given, together with selections of relevant examples from other experiments and
short overviews on new developments. Finally, the Alpha Magnetic Spectrometer
(AMS 02) experiment is briefly described as an impressive example of a
space-based experiment using a number of familiar PID techniques.Comment: 61 pages, 30 figure
AMS tracking in-orbit performance
AMS-02 is a high precision magnetic spectrometer for cosmic rays in the GeV
to TeV energy range. Its tracker consists of nine layers of double-sided
silicon microstrip sensors. They are used to locate the trajectories of cosmic
rays in the 0.14 T field of a cylindrical magnet, thus measuring their rigidity
and charge sign. In addition, they deliver a high resolution measurement
of the absolute charge . The detector has been designed to operate in
space with a position resolution of about 10 m for each hit and charge
identification capabilities up to . In this talk I describe the
performance in orbit of this detector component and its impact on the overall
performance of the spectrometer.Comment: 24th International Workshop on Vertex Detectors, 1-5 June 2015, Santa
Fe, New Mexico, US
Towards a new generation axion helioscope
We study the feasibility of a new generation axion helioscope, the most
ambitious and promising detector of solar axions to date. We show that large
improvements in magnetic field volume, x-ray focusing optics and detector
backgrounds are possible beyond those achieved in the CERN Axion Solar
Telescope (CAST). For hadronic models, a sensitivity to the axion-photon
coupling of \gagamma\gtrsim {\rm few} \times 10^{-12} GeV is
conceivable, 1--1.5 orders of magnitude beyond the CAST sensitivity. If axions
also couple to electrons, the Sun produces a larger flux for the same value of
the Peccei-Quinn scale, allowing one to probe a broader class of models. Except
for the axion dark matter searches, this experiment will be the most sensitive
axion search ever, reaching or surpassing the stringent bounds from SN1987A and
possibly testing the axion interpretation of anomalous white-dwarf cooling that
predicts of a few meV. Beyond axions, this new instrument will probe
entirely unexplored ranges of parameters for a large variety of axion-like
particles (ALPs) and other novel excitations at the low-energy frontier of
elementary particle physics.Comment: 37 pages, 11 figures, accepted for publication in JCA
From vertex detectors to inner trackers with CMOS pixel sensors
The use of CMOS Pixel Sensors (CPS) for high resolution and low material
vertex detectors has been validated with the 2014 and 2015 physics runs of the
STAR-PXL detector at RHIC/BNL. This opens the door to the use of CPS for inner
tracking devices, with 10-100 times larger sensitive area, which require
therefore a sensor design privileging power saving, response uniformity and
robustness. The 350 nm CMOS technology used for the STAR-PXL sensors was
considered as too poorly suited to upcoming applications like the upgraded
ALICE Inner Tracking System (ITS), which requires sensors with one order of
magnitude improvement on readout speed and improved radiation tolerance. This
triggered the exploration of a deeper sub-micron CMOS technology, Tower-Jazz
180 nm, for the design of a CPS well adapted for the new ALICE-ITS running
conditions. This paper reports the R&D results for the conception of a CPS well
adapted for the ALICE-ITS.Comment: 4 pages, 4 figures, VCI 2016 conference proceeding
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