252 research outputs found
Practical Verification of Decision-Making in Agent-Based Autonomous Systems
We present a verification methodology for analysing the decision-making component in agent-based hybrid systems. Traditionally hybrid automata have been used to both implement and verify such systems, but hybrid automata based modelling, programming and verification techniques scale poorly as the complexity of discrete decision-making increases making them unattractive in situations where complex log- ical reasoning is required. In the programming of complex systems it has, therefore, become common to separate out logical decision-making into a separate, discrete, component. However, verification techniques have failed to keep pace with this devel- opment. We are exploring agent-based logical components and have developed a model checking technique for such components which can then be composed with a sepa- rate analysis of the continuous part of the hybrid system. Among other things this allows program model checkers to be used to verify the actual implementation of the decision-making in hybrid autonomous systems
Higher-order multipole amplitudes in charmonium radiative transitions
Using 24 million decays in CLEO-c, we have searched
for higher multipole admixtures in electric-dipole-dominated radiative
transitions in charmonia. We find good agreement between our data and
theoretical predictions for magnetic quadrupole (M2) amplitudes in the
transitions and ,
in striking contrast to some previous measurements. Let and
denote the normalized M2 amplitudes in the respective aforementioned decays,
where the superscript refers to the angular momentum of the . By
performing unbinned maximum likelihood fits to full five-parameter angular
distributions, we determine the ratios and , where
the theoretical predictions are independent of the charmed quark magnetic
moment and are and .Comment: 32 pages, 7 figures, acceptance updat
Survey of Canadian Animal-Based Researchers' Views on the Three Rs: Replacement, Reduction and Refinement
The ‘Three Rs’ tenet (replacement, reduction, refinement) is a widely accepted cornerstone of Canadian and international policies on animal-based science. The Canadian Council on Animal Care (CCAC) initiated this web-based survey to obtain greater understanding of ‘principal investigators’ and ‘other researchers’ (i.e. graduate students, post-doctoral researchers etc.) views on the Three Rs, and to identify obstacles and opportunities for continued implementation of the Three Rs in Canada. Responses from 414 participants indicate that researchers currently do not view the goal of replacement as achievable. Researchers prefer to use enough animals to ensure quality data is obtained rather than using the minimum and potentially waste those animals if a problem occurs during the study. Many feel that they already reduce animal numbers as much as possible and have concerns that further reduction may compromise research. Most participants were ambivalent about re-use, but expressed concern that the practice could compromise experimental outcomes. In considering refinement, many researchers feel there are situations where animals should not receive pain relieving drugs because it may compromise scientific outcomes, although there was strong support for the Three Rs strategy of conducting animal welfare-related pilot studies, which were viewed as useful for both animal welfare and experimental design. Participants were not opposed to being offered “assistance” to implement the Three Rs, so long as the input is provided in a collegial manner, and from individuals who are perceived as experts. It may be useful for animal use policymakers to consider what steps are needed to make replacement a more feasible goal. In addition, initiatives that offer researchers greater practical and logistical support with Three Rs implementation may be useful. Encouragement and financial support for Three Rs initiatives may result in valuable contributions to Three Rs knowledge and improve welfare for animals used in science
Dalitz Plot Analysis of Ds to K+K-pi+
We perform a Dalitz plot analysis of the decay Ds to K+K-pi+ with the CLEO-c
data set of 586/pb of e+e- collisions accumulated at sqrt(s) = 4.17 GeV. This
corresponds to about 0.57 million D_s+D_s(*)- pairs from which we select 14400
candidates with a background of roughly 15%. In contrast to previous
measurements we find good agreement with our data only by including an
additional f_0(1370)pi+ contribution. We measure the magnitude, phase, and fit
fraction of K*(892) K+, phi(1020)pi+, K0*(1430)K+, f_0(980)pi+, f_0(1710)pi+,
and f_0(1370)pi+ contributions and limit the possible contributions of other KK
and Kpi resonances that could appear in this decay.Comment: 21 Pages,available through http://www.lns.cornell.edu/public/CLNS/,
submitted to PR
Search for D0 to p e- and D0 to pbar e+
Using data recorded by CLEO-c detector at CESR, we search for simultaneous
baryon and lepton number violating decays of the D^0 meson, specifically, D^0
--> p-bar e^+, D^0-bar --> p-bar e^+, D^0 --> p e^- and D^0-bar --> p e^-. We
set the following branching fraction upper limits: D^0 --> p-bar e^+ (D^0-bar
--> p-bar e^+) p e^- (D^0-bar --> p e^-) < 1.2 *
10^{-5}, both at 90% confidence level.Comment: 10 pages, available through http://www.lns.cornell.edu/public/CLNS/,
submitted to PRD. Comments: changed abstract, added reference for section 1,
vertical axis in Fig.5 changed (starts from 1.5 rather than 2.0), fixed typo
Charmonium decays to gamma pi0, gamma eta, and gamma eta'
Using data acquired with the CLEO-c detector at the CESR e+e- collider, we
measure branching fractions for J/psi, psi(2S), and psi(3770) decays to gamma
pi0, gamma eta, and gamma eta'. Defining R_n = B[ psi(nS)-->gamma eta ]/B[
psi(nS)-->gamma eta' ], we obtain R_1 = (21.1 +- 0.9)% and, unexpectedly, an
order of magnitude smaller limit, R_2 < 1.8% at 90% C.L. We also use
J/psi-->gamma eta' events to determine branching fractions of improved
precision for the five most copious eta' decay modes.Comment: 14 pages, available through http://www.lns.cornell.edu/public/CLNS/,
published in Physical Review
Precision Measurement of the Mass of the h_c(1P1) State of Charmonium
A precision measurement of the mass of the h_c(1P1) state of charmonium has
been made using a sample of 24.5 million psi(2S) events produced in e+e-
annihilation at CESR. The reaction used was psi(2S) -> pi0 h_c, pi0 -> gamma
gamma, h_c -> gamma eta_c, and the reaction products were detected in the
CLEO-c detector.
Data have been analyzed both for the inclusive reaction and for the exclusive
reactions in which eta_c decays are reconstructed in fifteen hadronic decay
channels. Consistent results are obtained in the two analyses. The averaged
results of the present measurements are M(h_c)=3525.28+-0.19 (stat)+-0.12(syst)
MeV, and B(psi(2S) -> pi0 h_c)xB(h_c -> gamma eta_c)= (4.19+-0.32+-0.45)x10^-4.
Using the 3PJ centroid mass, Delta M_hf(1P)= - M(h_c) =
+0.02+-0.19+-0.13 MeV.Comment: 9 pages, available through http://www.lns.cornell.edu/public/CLNS/,
submitted to PR
Precision Measurement of B(D+ -> mu+ nu) and the Pseudoscalar Decay Constant fD+
We measure the branching ratio of the purely leptonic decay of the D+ meson
with unprecedented precision as B(D+ -> mu+ nu) = (3.82 +/- 0.32 +/-
0.09)x10^(-4), using 818/pb of data taken on the psi(3770) resonance with the
CLEO-c detector at the CESR collider. We use this determination to derive a
value for the pseudoscalar decay constant fD+, combining with measurements of
the D+ lifetime and assuming |Vcd| = |Vus|. We find fD+ = (205.8 +/- 8.5 +/-
2.5) MeV. The decay rate asymmetry [B(D+ -> mu+ nu)-B(D- -> mu- nu)]/[B(D+ ->
mu+ nu)+B(D- -> mu- nu)] = 0.08 +/- 0.08, consistent with no CP violation. We
also set 90% confidence level upper limits on B(D+ -> tau+ nu) < 1.2x10^(-3)
and B(D+ -> e+ nu) < 8.8x10^(-6).Comment: 24 pages, 11 figures and 6 tables, v2 replaced some figure vertical
axis scales, v3 corrections from PRD revie
J/psi and psi(2S) Radiative Transitions to eta_c
Using 24.5 million psi(2S) decays collected with the CLEO-c detector at CESR
we present the most precise measurements of magnetic dipole transitions in the
charmonium system. We measure B(psi(2S)->gamma eta_c) =
(4.32+/-0.16+/-0.60)x10^-3, B(J/psi->gamma eta_c)/B(psi(2S)->gamma eta_c) =
4.59+/-0.23+/-0.64, and B(J/psi->gamma eta_c) = (1.98+/-0.09+/-0.30)%. We
observe a distortion in the eta_c line shape due to the photon-energy
dependence of the magnetic dipole transition rate. We find that measurements of
the eta_c mass are sensitive to the line shape, suggesting an explanation for
the discrepancy between measurements of the eta_c mass in radiative transitions
and other production mechanisms.Comment: 11 pages, 3 figure
Inclusive chi_bJ(nP) Decays to D0 X
Using Upsilon(2S) and Upsilon(3S) data collected with the CLEO III detector
we have searched for decays of chi_bJ to final states with open charm. We fully
reconstruct D0 mesons with p_D0 > 2.5 GeV/c in three decay modes (K-pi+,
K-pi+pi0, and K-pi-pi+pi+) in coincidence with radiative transition photons
that tag the production of one of the chi_bJ(nP) states. We obtain significant
signals for the two J=1 states. Recent NRQCD calculations of chi_{bJ}(nP) --> c
cbar X depend on one non-perturbative parameter per chi_bJ triplet. The
extrapolation from the observed D0 X rate over a limited momentum range to a
full c cbar X rate also depends on these same parameters. Using our data to fit
for these parameters, we extract results which agree well with NRQCD
predictions, confirming the expectation that charm production is largest for
the J=1 states. In particular, for J=1, our results are consistent with c cbar
g accounting for about one-quarter of all hadronic decays.Comment: Version 2 updates include corrections to important errors in Table V
and VII column headers which summarize results, and additional minor edits.
17 pages, available through http://www.lns.cornell.edu/public/CLNS
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