3,333 research outputs found
Kaon physics with the KLOE detector
In this paper we discuss the recent finalized analyses by the KLOE experiment
at DANE: the CPT and Lorentz invariance test with entangled pairs, and the precision measurement of the branching fraction of
the decay . We also present the
status of an ongoing analysis aiming to precisely measure the mass
A Human-Robot Interaction Perspective on Assistive and Rehabilitation Robotics
Assistive and rehabilitation devices are a promising and challenging field of recent robotics research. Motivated by societal needs such as aging populations, such devices can support motor functionality and subject training. The design, control, sensing, and assessment of the devices become more sophisticated due to a human in the loop. This paper gives a human–robot interaction perspective on current issues and opportunities in the field. On the topic of control and machine learning, approaches that support but do not distract subjects are reviewed. Options to provide sensory user feedback that are currently missing from robotic devices are outlined. Parallels between device acceptance and affective computing are made. Furthermore, requirements for functional assessment protocols that relate to real-world tasks are discussed. In all topic areas, the design of human-oriented frameworks and methods is dominated by challenges related to the close interaction between the human and robotic device. This paper discusses the aforementioned aspects in order to open up new perspectives for future robotic solutions
KLOE results in kaon physics and prospects for KLOE-2
The phi-factory DAPHNE offers a possibility to select pure kaon beams,
charged and neutral ones. In particular, neutral kaons from phi->KS KL are
produced in pairs and the detection of a KS (KL) tags the presence of a KL
(KS). This allows to perform precise measurements of kaon properties by means
of KLOE detector. Another advantage of a phi-factory consists in fact that the
neutral kaon pairs are produced in a pure quantum state (J^(PC) = 1^(--)),
which allowsto investigate CP and CPT symmetries via quantum interference
effects, as well as the basic principles of quantum mechanics.A review of the
most recent results of the KLOE experiment at DAPHNE using pure kaon beams or
via quantum interferometry is presented together with prospects for kaon
physics at KLOE-2.Comment: 5 pages, 4 figures, From Phi To Psi 2011 conference, to be published
in Nuclear Physics B (Proceedings Supplements
Search for dark Higgsstrahlung in e+ e- -> mu+ mu- and missing energy events with the KLOE experiment
We searched for evidence of a Higgsstrahlung process in a secluded sector,
leading to a final state with a dark photon U and a dark Higgs boson h', with
the KLOE detector at DAFNE. We investigated the case of h' lighter than U, with
U decaying into a muon pair and h' producing a missing energy signature. We
found no evidence of the process and set upper limits to its parameters in the
range 2m_mu<m_U<1000 MeV, m_h'<m_U.Comment: 16 pages, 7 figures, submitted to Physics Letters
Limit on the production of a new vector boson in , U with the KLOE experiment
The recent interest in a light gauge boson in the framework of an extra U(1)
symmetry motivates searches in the mass range below 1 GeV.
We present a search for such a particle, the dark photon, in , U based on 28 million
events collected at DANE
by the KLOE experiment. The production by initial-state radiation
compensates for a loss of sensitivity of previous KLOE , searches due to the small branching ratios in
the resonance region. We found no evidence for a signal and set a
limit at 90\% CL on the mixing strength between the photon and the dark photon,
, in the U mass range between and ~MeV. Above 700 MeV
this new limit is more stringent than previous ones.Comment: 6 pages, 9 figures, 1 table, submitted to Phys. Lett.
Measurement of the transition form factor with the KLOE detector
A measurement of the vector to pseudoscalar conversion decay with the KLOE experiment is presented. A sample of signal
events was selected from a data set of 1.7 fb of collisions at
collected at the DANE collider. These
events were used to obtain the first measurement of the transition form factor
and a new measurement of the branching ratio of the
decay: . The result improves
significantly on previous measurements and is in agreement with theoretical
predictions.Comment: 13 pages, 4 figures; matches published versio
Precision measurement of and determination of the contribution to the muon anomaly with the KLOE detector
We have measured the ratio
, with the KLOE detector at DANE for a total integrated
luminosity of 240 pb. From this ratio we obtain the cross section
. From the cross section we determine the
pion form factor and the two-pion contribution to the muon anomaly
for GeV, = . This result confirms the
current discrepancy between the Standard Model calculation and the experimental
measurement of the muon anomaly.Comment: 18 pages, 8 figures, minor text corrections, one table added, version
to appear on Physics Letters
Precision measurement of the Dalitz plot distribution with the KLOE detector
Using fb of data collected with
the KLOE detector at DANE, the Dalitz plot distribution for the decay is studied with the world's largest sample of events. The Dalitz plot density is parametrized as a polynomial
expansion up to cubic terms in the normalized dimensionless variables and
. The experiment is sensitive to all charge conjugation conserving terms of
the expansion, including a term. The statistical uncertainty of all
parameters is improved by a factor two with respect to earlier measurements.Comment: 11 pages, 9 figures, supplement: an ascii tabl
Measurement of \Gamma(\eta -> \pi^+\pi^-\gamma)/\Gamma(\eta -> \pi^+\pi^-\pi^0) with the KLOE Detector
The ratio R_{\eta}=\Gamma(\eta -> \pi^+\pi^-\gamma)/\Gamma(\eta ->
\pi^+\pi^-\pi^0) has been measured by analyzing 22 million \phi \to \eta \gamma
decays collected by the KLOE experiment at DA\PhiNE, corresponding to an
integrated luminosity of 558 pb^{-1}. The \eta \to \pi^+\pi^-\gamma proceeds
both via the \rho resonant contribution, and possibly a non-resonant direct
term, connected to the box anomaly. Our result, R_{\eta}= 0.1856\pm
0.0005_{stat} \pm 0.0028_{syst}, points out a sizable contribution of the
direct term to the total width. The di-pion invariant mass for the \eta ->
\pi^+\pi^-\gamma decay could be described in a model-independent approach in
terms of a single free parameter, \alpha. The determined value of the parameter
\alpha is \alpha = (1.32 \pm 0.08_{stat} +0.10/-0.09_{syst}\pm 0.02_{theo})
GeV^{-2}Comment: Paper in press, accepted by PL
Search for the K_S -> e+e- decay with the KLOE detector
We present the result of a direct search for the decay K_S -> e+e-, obtained
with a sample of e+e- -> phi -> K_S K_L events produced at DAFNE, the Frascati
phi-factory, for an integrated luminosity of 1.9 fb^-1. The search has been
performed using a pure K_S beam tagged by the simultaneous detection of a K_L
interaction in the calorimeter. Background rejection has been optimized by
using both kinematic and particle identification cuts. We find BR(K_S -> e+e-)
< 9x10^-9 at 90% CL, which improves by an order of magnitude on the previous
best limit.Comment: 13 pages, 11 figures, submitted to Physics Letters
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