303,520 research outputs found
A New Technique for Detecting Supersymmetric Dark Matter
We estimate the event rate for excitation of atomic transition by
photino-like dark matter. For excitations of several eV, this event rate can
exceed naive cross-section by many orders of magnitude. Although the event rate
for these atomic excitation is smaller than that of nuclear recoil off of
non-zero spin nuclei, the photons emitted by the deexcitation are easier to
detect than low-energy nuclear recoils. For many elements, there are several
low-lying states with comparable excitation rates, thus, spectral ratios could
be used to distinguish signal from background.Comment: 6 pages plain te
Mass and charge identification of fragments detected with the Chimera Silicon-CsI(Tl) telescopes
Mass and charge identification of charged products detected with
Silicon-CsI(Tl) telescopes of the Chimera apparatus is presented. An
identification function, based on the Bethe-Bloch formula, is used to fit
empirical correlation between Delta E and E ADC readings, in order to
determine, event by event, the atomic and mass numbers of the detected charged
reaction products prior to energy calibration.Comment: 24 pages, 7 .jpg figures, submitted to Nucl.Instr.
Atomic components
There has been much interest in components that combine the best of state-based and event-based approaches. The interface of a component can be thought of as its specification and substituting components with the same interface cannot be observed by any user of the components. Here we will define the semantics of atomic components where both states and event can be part of the interface. The resulting semantics is very similar to that of (event only) processes. But it has two main novelties: one, it does not need recursion or unique fixed points to model nontermination; and two, the behaviour of divergence is modelled by abstraction, i.e. the construction of the observational semantics
Contact Interactions and high Events at HERA
Effective contact interactions can enhance event rates in
scattering at HERA at high . Present constraints from atomic parity
violation measurements and from Drell Yan events at the Tevatron are discussed.Comment: 3 pages, Latex, Talk given at 5th International Workshop on Deep
Inelastic Scattering and QCD, Chicago, Illinois, USA, 14-18 April 199
Motion as manipulation: Implementation of motion and force analogies by event-file binding and action planning\ud
Tool improvisation analogies are a special case of motion and force analogies that appear to be implemented pre-conceptually, in many species, by event-file binding and action planning. A detailed reconstruction of the analogical reasoning steps involved in Rutherford's and Bohr's development of the first quantized-orbit model of atomic structure is used to show that human motion and force analogies generally can be implemented by the event-file binding and action planning mechanism. Predictions that distinguish this model from competing concept-level models of analogy are discussed, available data pertaining to them are reviewed, and further experimental tests are proposed
Dense-ATOMIC: Towards Densely-connected ATOMIC with High Knowledge Coverage and Massive Multi-hop Paths
ATOMIC is a large-scale commonsense knowledge graph (CSKG) containing
everyday if-then knowledge triplets, i.e., {head event, relation, tail event}.
The one-hop annotation manner made ATOMIC a set of independent bipartite
graphs, which ignored the numerous links between events in different bipartite
graphs and consequently caused shortages in knowledge coverage and multi-hop
paths. In this work, we aim to construct Dense-ATOMIC with high knowledge
coverage and massive multi-hop paths. The events in ATOMIC are normalized to a
consistent pattern at first. We then propose a CSKG completion method called
Rel-CSKGC to predict the relation given the head event and the tail event of a
triplet, and train a CSKG completion model based on existing triplets in
ATOMIC. We finally utilize the model to complete the missing links in ATOMIC
and accordingly construct Dense-ATOMIC. Both automatic and human evaluation on
an annotated subgraph of ATOMIC demonstrate the advantage of Rel-CSKGC over
strong baselines. We further conduct extensive evaluations on Dense-ATOMIC in
terms of statistics, human evaluation, and simple downstream tasks, all proving
Dense-ATOMIC's advantages in Knowledge Coverage and Multi-hop Paths. Both the
source code of Rel-CSKGC and Dense-ATOMIC are publicly available on
https://github.com/NUSTM/Dense-ATOMIC.Comment: Accepted by ACL 2023 Main Conferenc
Single spontaneous photon as a coherent beamsplitter for an atomic matterwave
In spontaneous emission an atom in an excited state undergoes a transition to
the ground state and emits a single photon. Associated with the emission is a
change of the atomic momentum due to photon recoil. Photon emission can be
modified close to surfaces and in cavities. For an ion, localized in front of a
mirror, coherence of the emitted resonance fluorescence has been reported. In
free space experiments demonstrated that spontaneous emission destroys motional
coherence. Here we report on motional coherence created by a single spontaneous
emission event close to a mirror surface. The coherence in the free atomic
motion is verified by atom interferometry. The photon can be regarded as a
beamsplitter for an atomic matterwave and consequently our experiment extends
the original recoiling slit Gedanken experiment by Einstein to the case where
the slit is in a robust coherent superposition of the two recoils associated
with the two paths of the quanta.Comment: main text: 5 pages, 4 figure; supplementary information: 8 pages, 1
figur
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