701 research outputs found
Two charged strangeonium-like structures observable in the process
Via the Initial Single Pion Emission (ISPE) mechanism, we study the
invariant mass spectrum distribution of . Our calculation indicates there exist a sharp peak
structure () close to the threshold and a broad
structure () near the threshold. In addition, we
also investigate the process due to
the ISPE mechanism, where a sharp peak around the threshold
appears in the invariant mass spectrum distribution. We
suggest to carry out the search for these charged strangeonium-like structures
in future experiment, especially Belle II, Super-B and BESIII.Comment: 7 pages, 5 figures. Accepted by Eur. Phys. J.
Chinaâs emerging global role: dissatisfied responsible great power
China has (re)emerged as a great power in a world not of its own making. The distribution of power in major organisations and the dominant norms of international interactions are deemed to unfairly favour the existing Western powers, and at times obstruct Chinaâs ability to meet national development goals. Nevertheless, engaging the global economy has been a key source of economic growth (thus helping to maintain regime stability), and establishing Chinaâs credentials as a responsible global actor is seen as a means of ensuring continued access to what China needs. As an emerging great power that is also still in many respects a developing country, Chinaâs challenge is to change the global order in ways that do not cause global instability or generate crises that would damage Chinaâs own ability to generate economic growth and ensure political stability
Rapid Accurate Calculation of the s-Wave Scattering Length
Transformation of the conventional radial Schr\"odinger equation defined on
the interval into an equivalent form defined on the finite
domain allows the s-wave scattering length to be
exactly expressed in terms of a logarithmic derivative of the transformed wave
function at the outer boundary point , which corresponds to
. In particular, for an arbitrary interaction potential that dies off
as fast as for , the modified wave function obtained
by using the two-parameter mapping function has no singularities, and
For
a well bound potential with equilibrium distance , the optimal mapping
parameters are and . An
outward integration procedure based on Johnson's log-derivative algorithm
[B.R.\ Johnson, J.\ Comp.\ Phys., \textbf{13}, 445 (1973)] combined with a
Richardson extrapolation procedure is shown to readily yield high precision
-values both for model Lennard-Jones () potentials and for realistic
published potentials for the Xe--e, Cs_2(a\,^3\Sigma_u^+) and
He_2(X\,^1\Sigma_g^+) systems. Use of this same transformed
Schr{\"o}dinger equation was previously shown [V.V. Meshkov et al., Phys.\
Rev.\ A, {\bf 78}, 052510 (2008)] to ensure the efficient calculation of all
bound levels supported by a potential, including those lying extremely close to
dissociation.Comment: 12 pages, 9 figures, to appear in J. Chem. Phy
Revisiting the Local Scaling Hypothesis in Stably Stratified Atmospheric Boundary Layer Turbulence: an Integration of Field and Laboratory Measurements with Large-eddy Simulations
The `local scaling' hypothesis, first introduced by Nieuwstadt two decades
ago, describes the turbulence structure of stable boundary layers in a very
succinct way and is an integral part of numerous local closure-based numerical
weather prediction models. However, the validity of this hypothesis under very
stable conditions is a subject of on-going debate. In this work, we attempt to
address this controversial issue by performing extensive analyses of turbulence
data from several field campaigns, wind-tunnel experiments and large-eddy
simulations. Wide range of stabilities, diverse field conditions and a
comprehensive set of turbulence statistics make this study distinct
Higher order WKB corrections to black hole entropy in brick wall formalism
We calculate the statistical entropy of a quantum field with an arbitrary
spin propagating on the spherical symmetric black hole background by using the
brick wall formalism at higher orders in the WKB approximation. For general
spins, we find that the correction to the standard Bekenstein-Hawking entropy
depends logarithmically on the area of the horizon. Furthermore, we apply this
analysis to the Schwarzschild and Schwarzschild-AdS black holes and discuss our
results.Comment: 21 pages, published versio
Partial Wave Analysis of
BES data on are presented. The
contribution peaks strongly near threshold. It is fitted with a
broad resonance with mass MeV, width MeV. A broad resonance peaking at 2020 MeV is also required
with width MeV. There is further evidence for a component
peaking at 2.55 GeV. The non- contribution is close to phase
space; it peaks at 2.6 GeV and is very different from .Comment: 15 pages, 6 figures, 1 table, Submitted to PL
Search for antihelium in cosmic rays
The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle
Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320
and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity
range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper
limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.Comment: 18 pages, Latex, 9 .eps figure
Phenomenology of Pc(4380)+, Pc(4450)+ and related states
The and states recently discovered at LHCb have
masses close to several relevant thresholds, which suggests they can be
described in terms of meson-baryon degrees of freedom. This article explores
the phenomenology of these states, and their possible partners, from this point
of view. Competing models can be distinguished by the masses of the neutral
partners which have yet to be observed, and the existence or otherwise of
further partners with different isospin, spin, and parity. Future experimental
studies in different decay channels can also discriminate among models, using
selection rules and algebraic relations among decays. Among the several
possible meson-baryon pairs which could be important, one implies that the
states are mixtures of isospins 1/2 and 3/2, with characteristic signatures in
production and decay. A previous experimental study of a Cabibbo-suppressed
decay showed no evidence for the states, and further analysis is required to
establish the significance of this non-observation. Several intriguing
similarities suggest that is related to the meson.Comment: 16 pages, 1 figure. Journal version (some very minor changes from
arXiv v1
Ultra violet sensors based on nanostructured ZnO spheres in network of nanowires: a novel approach
The ZnO nanostructures consisting of micro spheres in a network of nano wires were synthesized by direct vapor phase method. X-ray Photoelectron Spectroscopy measurements were carried out to understand the chemical nature of the sample. ZnO nanostructures exhibited band edge luminescence at 383 nm. The nanostructure based ZnO thin films were used to fabricate UV sensors. The photoresponse measurements were carried out and the responsivity was measured to be 50 mA Wâ1. The rise and decay time measurements were also measured
Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV
The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3
magnetic muon spectrometer for zenith angles ranging from 0 degree to 58
degree. Due to the large exposure of about 150 m2 sr d, and the excellent
momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in
the vertical direction is achieved.
The ratio of positive to negative muons is studied between 20 GeV and 500
GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003
(stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure
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