2,146 research outputs found
INTEGRATED GEOPHYSICAL INVESTIGATION OF KARST FEATURES – INNER BLUEGRASS REGION OF KENTUCKY
High-resolution electrical-resistivity, seismic-refraction, and seismic-reflection surveys were performed at three locations in the Inner Bluegrass Region of Kentucky along coincident survey lines in order to correlate results and determine which method is most effective at locating karst features in this area. The first two survey locations at Slack’s Cave and the Kentucky Horse Park were chosen in order to investigate known karst features. High and low electrical-resistivity anomalies were correlated to air- and water-filled karst voids, respectively. Seismic velocity anomalies, including parabolic time suppressions, amplitude terminations, and surface-wave backscatters, were also observed and correlated to these karst voids. These findings were applied to a third location along Berea Road in order to investigate undiscovered karst voids. Three seismic targets were selected based on backscatter anomaly locations and were aligned in a northwest trend following the general bedrock dip, joint orientations, and suspected conduit orientation. Overall, the seismic-reflection method provided the highest resolution and least ambiguous results; however, integration of multiple methods was determined to help decrease ambiguities in interpretation created by the inherent non-uniqueness found in the results of each method
Bounds on the slope and the curvature of the scalar K\pi form factor at zero momentum transfer
We derive and calculate unitarity bounds on the slope and curvature of the
strangeness-changing scalar form factor at zero momentum transfer, using
low-energy constraints and Watson final state interaction theorem. The results
indicate that the curvature is important and should not be neglected in the
representation of experimental data. The bounds can be converted also into an
allowed region for the constants and of Chiral
Perturbation Theory. Our results are consistent with, but weaker than the
predictions made by Jamin, Oller and Pich in a coupled channel dispersion
approach basedon chiral resonance model. We comment on the differences between
the two dispersive methods and argue that the unitarity bounds are useful as an
independent check involving different sources of informationComment: 25 pages, 5 figures, version to be published in Nuclear Physics
Scalar K pi form factor and light quark masses
Recent experimental improvements on K-decay data allow for a precise
extraction of the strangeness-changing scalar K pi form factor and the related
strange scalar spectral function. On the basis of this scalar as well as the
corresponding pseudoscalar spectral function, the strange quark mass is
determined to be m_s(2 GeV) = 92 +- 9 MeV. Further taking into account chiral
perturbation theory mass ratios, the light up and down quark masses turn out to
be m_u(2 GeV) = 2.7 +- 0.4 MeV as well as m_d(2 GeV) = 4.8 +- 0.5 MeV. As a
by-product, we also find a value for the Cabibbo angle |V_{us}| = 0.2236(29)
and the ratio of meson decay constants F_K/F_\pi = 1.203(16). Performing a
global average of the strange mass by including extractions from other channels
as well as lattice QCD results yields m_s(2 GeV) = 94 +- 6 MeV.Comment: 5 pages, 2 figures; comparison with lattice and global average added;
version to appear in Phys. Rev.
Precise Determination of |V{us}| from Lattice Calculations of Pseudoscalar Decay Constants
Combining the ratio of experimental kaon and pion decay widths, Gamma(K to mu
antineutrino{mu} (gamma)) / Gamma(pi to mu \antineutrino (gamma)), with a
recent lattice gauge theory calculation of f{K}/f{pi} provides a precise value
for the CKM quark mixing matrix element |V{us}|=0.2236(30) or if 3 generation
unitarity is assumed |V{us}|=0.2238(30). Comparison with other determinations
of that fundamental parameter, implications, and an outlook for future
improvements are given
Corrections to the Gell-Mann-Oakes-Renner relation and chiral couplings and
Next to leading order corrections to the
Gell-Mann-Oakes-Renner relation (GMOR) are obtained using weighted QCD Finite
Energy Sum Rules (FESR) involving the pseudoscalar current correlator. Two
types of integration kernels in the FESR are used to suppress the contribution
of the kaon radial excitations to the hadronic spectral function, one with
local and the other with global constraints. The result for the pseudoscalar
current correlator at zero momentum is , leading to the chiral corrections to GMOR: . The resulting uncertainties are mostly due to variations in the upper
limit of integration in the FESR, within the stability regions, and to a much
lesser extent due to the uncertainties in the strong coupling and the strange
quark mass. Higher order quark mass corrections, vacuum condensates, and the
hadronic resonance sector play a negligible role in this determination. These
results confirm an independent determination from chiral perturbation theory
giving also very large corrections, i.e. roughly an order of magnitude larger
than the corresponding corrections in chiral . Combining
these results with our previous determination of the corrections to GMOR in
chiral , , we are able to determine two low
energy constants of chiral perturbation theory, i.e. , and , both at the
scale of the -meson mass.Comment: Revised version with minor correction
Up and down quark masses from Finite Energy QCD sum rules to five loops
The up and down quark masses are determined from an optimized QCD Finite
Energy Sum Rule (FESR) involving the correlator of axial-vector divergences, to
five loop order in Perturbative QCD (PQCD), and including leading
non-perturbative QCD and higher order quark mass corrections. This FESR is
designed to reduce considerably the systematic uncertainties arising from the
(unmeasured) hadronic resonance sector, which in this framework contributes
less than 3-4% to the quark mass. This is achieved by introducing an
integration kernel in the form of a second degree polynomial, restricted to
vanish at the peak of the two lowest lying resonances. The driving hadronic
contribution is then the pion pole, with parameters well known from experiment.
The determination is done in the framework of Contour Improved Perturbation
Theory (CIPT), which exhibits a very good convergence, leading to a remarkably
stable result in the unusually wide window , where
is the radius of the integration contour in the complex energy (squared)
plane. The results are: MeV, MeV, and Mev (at a scale Q=2 GeV).Comment: Additional references to lattice QCD results have been adde
Stringent constraints on the scalar K pi form factor from analyticity, unitarity and low-energy theorems
We investigate the scalar K pi form factor at low energies by the method of
unitarity bounds adapted so as to include information on the phase and modulus
along the elastic region of the unitarity cut. Using at input the values of the
form factor at t=0 and the Callan-Treiman point, we obtain stringent
constraints on the slope and curvature parameters of the Taylor expansion at
the origin. Also, we predict a quite narrow range for the higher order ChPT
corrections at the second Callan-Treiman point.Comment: 5 pages latex, uses EPJ style files, 3 figures, replaced with version
accepted by EPJ
Possible explanation of the discrepancy of the light-cone QCD sum rule calculation of g(D*Dpi) coupling with experiment
The introduction of an explicit negative radial excitation contribution in
the hadronic side of the light cone QCD sum rule (LCSR) of Belyaev, Braun,
Khodjamirian and Ruckl, can explain the large experimental value of g(D*Dpi),
recently measured by CLEO. At the same time, it considerably improves the
stability of the sum rule when varying the Borel parameter.Comment: 9 pages, 1 PostScript figure
Uji Adaptasi Beberapa Klon Karet pada Elevasi Tinggi
Lahan yang ideal untuk pertumbuhan tanaman karet semakin terbatas sehingga banyak petani dan Perusahaan mencari lahan pengembangan karet di daerah non tradisional seperti lahan pada > 500 m di atas permukaan laut (mdpl). Penelitian dilakukan di Kabupaten Muara Enim pada elevasi 760 mdpl. Penelitian bertujuan untuk mendapatkan informasi pertumbuhan dan produksi beberapa klon karet pada elevasi tinggi. Rancangan yang digunakan adalah Rancangan Acak Kelompok dengan klon sebagai perlakuan dan diulang sebanyak empat kali. Klon yang diuji adalah PB 260, RRIC 100, BPM 24, GT 1 dan IRR 39. Hasil penelitian menunjukkan bahwa tanaman karet pada elevasi tinggi dengan perawatan sesuai anjuran akan mampu matang sadap pada umur lima tahun. Pertumbuhan klon karet paling cepat pada elevasi tinggi 760 m dpl secara berurutan adalah IRR 39, RRIC 100, PB 260, BPM 24 dan GT 1, sedangkan produksi paling tinggi adalah PB 260, RRIC 100, BPM 24, GT 1 dan IRR 39
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