138 research outputs found
Calculation of and Couplings in QCD Sum Rules
We calculate the coupling constants, and $, which is also important
in the calculation of the S_{11}(1535) mass itself within the sum rule
approach.Comment: 8 pages (no figure), revte
Two-point correlation function with pion in QCD sum rules
Within the framework of the conventional QCD sum rules, we study the pion
two-point correlation function, , beyond the soft-pion limit. We construct sum rules from the
three distinct Dirac structures, i \gamma_5 \notp, i \gamma_5, \gamma_5
\sigma_{\mu \nu} {q^\mu p^\nu} and study the reliability of each sum rule. The
sum rule from the third structure is found to be insensitive to the continuum
threshold, , and contains relatively small contribution from the
undetermined single pole which we denote as . The sum rule from the structure is very different even though it contains similar
contributions from and as the ones coming from the structure. On the other hand, the sum rule from
the i \gamma_5 \notp structure has strong dependence on both and ,
which is clearly in constrast with the sum rule for . We identify the source of the sensitivity for each of the sum
rules by making specific models for higher resonance contributions and discuss
the implication.Comment: slightly revised. version accepted for publication in Physical Review
Intimate Monolithic integration of Chip-scale Photonic Circuits
Cataloged from PDF version of article.In this paper, we introduce a robust monolithic integration technique for fabricating photonic integrated circuits comprising optoelectronic devices (e.g., surface-illuminated photodetectors, waveguide quantum-well modulators, etc.) that are made of completely separate epitaxial structures and possibly reside at different locations across the wafer as necessary. Our technique is based on the combination of multiple crystal growth steps, judicious placement of epitaxial etch-stop layers, a carefully designed etch sequence, and self-planarization and passivation steps to compactly integrate optoelectronic devices. This multigrowth integration technique is broadly applicable to most III-V materials and can be exploited to fabricate sophisticated, highly integrated, multifunctional photonic integrated circuits on a single substrate. As a successful demonstration of this technique, we describe integrated photonic switches that consume only a 300 x 300 mu m footprint and incorporate InGaAs photodetector mesas and InGaAsP/InP quantum-well modulator waveguides separated by 50 mu m on an InP substrate. These switches perform electrically-reconfigurable optically-controlled wavelength conversion at multi-Gb/s data rates over the entire center telecommunication wavelength band
Charmed Exotics in Heavy Ion Collisions
Based on the color-spin interaction in diquarks, we argue that charmed
multiquark hadrons are likely to exist. Because of the appreciable number of
charm quarks produced in central nucleus-nucleus collisions at
ultrarelativistic energies, production of charmed multiquark hadrons is
expected to be enhanced in these collisions. Using both the quark coalescence
model and the statistical hadronization model, we estimate the yield of charmed
tetraquark meson and pentaquark baryon in heavy ion
collisions at RHIC and LHC. We further discuss the decay modes of these charmed
exotic hadrons in order to facilitate their detections in experiments
Molecular identification of adenoviruses associated with respiratory infection in Egypt from 2003 to 2010.
BACKGROUND: Human adenoviruses of species B, C, and E (HAdV-B, -C, -E) are frequent causative agents of acute respiratory infections worldwide. As part of a surveillance program aimed at identifying the etiology of influenza-like illness (ILI) in Egypt, we characterized 105 adenovirus isolates from clinical samples collected between 2003 and 2010. METHODS: Identification of the isolates as HAdV was accomplished by an immunofluorescence assay (IFA) and confirmed by a set of species and type specific polymerase chain reactions (PCR). RESULTS: Of the 105 isolates, 42% were identified as belonging to HAdV-B, 60% as HAdV-C, and 1% as HAdV-E. We identified a total of six co-infections by PCR, of which five were HAdV-B/HAdV-C co-infections, and one was a co-infection of two HAdV-C types: HAdV-5/HAdV-6. Molecular typing by PCR enabled the identification of eight genotypes of human adenoviruses; HAdV-3 (n = 22), HAdV-7 (n = 14), HAdV-11 (n = 8), HAdV-1 (n = 22), HAdV-2 (20), HAdV-5 (n = 15), HAdV-6 (n = 3) and HAdV-4 (n = 1). The most abundant species in the characterized collection of isolates was HAdV-C, which is concordant with existing data for worldwide epidemiology of HAdV respiratory infections. CONCLUSIONS: We identified three species, HAdV-B, -C and -E, among patients with ILI over the course of 7 years in Egypt, with at least eight diverse types circulating
Progress in the determination of the cross section
Improving previous calculations, we compute the cross section using QCD sum rules. Our sum rules for the , , and hadronic
matrix elements are constructed by using vaccum-pion correlation functions, and
we work up to twist-4 in the soft-pion limit. Our results suggest that, using
meson exchange models is perfectly acceptable, provided that they include form
factors and that they respect chiral symmetry. After doing a thermal average we
get mb at T=150\MeV.Comment: 22 pages, RevTeX4 including 7 figures in ps file
Distinct inhibitory effects on mTOR signaling by ethanol and INK128 in diffuse large B-cell lymphoma
Contribution of Quark-Mass-Dependent Operators to Higher Twist Effects in DIS
We look at the contribution of Quark-Mass-dependent twist-4 operators to the
second moments of spin averaged structure functions and the Bjorken sum rule.
Its contribution is non-negligible in the former case due to large Wilson
coefficients. We also discuss the values of the twist- 4 spin-2 nucleon matrix
element within present experimental constraints.Comment: 14pages, RevTex, (To be published in Phys. Rev. D) University of
Washington preprint DOE/ER/40427-22-N9
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