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81.
We calculate the strong coupling constants of light pseudoscalar mesons with heavy baryons within the light cone QCD sum rules method. It is shown that sextet–sextet, sextet–antitriplet and antitriplet–antitriplet transitions are described by one universal invariant function for each class. A comparison of our results on the coupling constants with the predictions existing in literature is also presented. 相似文献
82.
Yusuf Öztürk Asım Egemen Yılmaz Evrim Çolak Ekmel Özbay 《Photonics and Nanostructures》2012,10(4):624-631
Planar metamaterials, which have incident to normal plane excitation unlike SRR-type structures and that are easily fabricated in multilayer form, have received great interest in recent years. In this paper, one-dimensional and polarization independent circular fishnet metamaterials and their equivalent discontinuous slab-pair modeling for tuning resonance frequencies are introduced. After the numerical and experimental demonstration of the inclusions, the standard retrieval characterization methods and the correspondent/related backward-wave propagation observation are realized in order to check the physical explanation mentioned in the paper. In addition, a detailed phase analysis is performed in order to demonstrate the application of the suggested structure as a phase compensator. 相似文献
83.
84.
A. Martınez Torres K. P. Khemchandani E. Oset 《The European Physical Journal A - Hadrons and Nuclei》2008,35(3):295-297
We discuss the dynamical generation of some low-lying 1/2+ Σ 's and Λ 's in two-meson one-baryon systems. These systems have been constructed by adding a pion in the S -wave to the ˉN pair and its coupled channels, where the 1/2- Λ(1405) -resonance gets dynamically generated. We solve Faddeev equations in the coupled-channel approach to calculate the
T -matrix for these systems as a function of the total energy and the invariant mass of one of the meson-baryon pairs. This
squared T -matrix shows peaks at the energies very close to the masses of the strangeness -1 , 1/2+ resonances listed in the particle data book. 相似文献
85.
O. Çakır İ. T. Çakır H. Duran Yıldız R. Mehdiyev 《The European Physical Journal C - Particles and Fields》2008,56(4):537-543
We study the single production of fourth-family quarks through the process pp→Q′jX at the Large Hadron Collider (LHC). We have calculated the decay widths and branching ratios of the fourth-family quarks
(b′ and t′) in the mass range 300–800 GeV. The cross sections for the signal and background processes have been calculated in a Monte
Carlo framework. It is shown that the LHC can discover single t′ and b′ quarks if the CKM matrix elements |V
t′q
|,|V
qb′|≳0.01. 相似文献
86.
C. Garcıa-Recio J. Nieves L. L. Salcedo 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):540-542
Starting from a consistent SU(6) extension of the Weinberg-Tomozawa (WT) meson-baryon chiral Lagrangian ( Phys. Rev. D 74, 034025 (2006)), we study the s-wave meson-baryon resonances in the strangeness S = - 3 and negative-parity sectors. Those resonances are generated by solving the Bethe-Salpeter equation with the WT interaction
used as kernel. The considered mesons are those of the 35-SU(6)-plet, which includes the pseudoscalar (PS) octet of pions and the vector (V) nonet of the rho-meson. For baryons we consider
the 56-SU(6)-plet, made of the 1/2+ octet of the nucleon and the 3/2+ decuplet of the Delta. Quantum numbers I(J
P) = 0(3/2-) are suggested for the experimental resonances Ω
*(2250)- and Ω
*(2380)-. Among other, resonances with I = 1 are found, which minimal quark content is sssˉl', being s the strange quark and l, l' any of the the light up or down quarks. A clear signal for such a pentaquark would be a baryonic resonance with strangeness -3 and electric charge -2 or
0, in proton charge units. We suggest looking for K
-
Ξ
- resonances with masses around 2100 and 2240MeV in the sector 1(1/2-), and for π
±
Ω
- and K
-
Ξ
*- resonances with masses around 2260MeV in the sector 1(3/2-). 相似文献
87.
B. Saghai J. -C. David B. Juliá-Dıaz T. -S. H. Lee 《The European Physical Journal A - Hadrons and Nuclei》2007,31(4):512-514
Differential cross-section and single polarization observables in the process γp→K
+
Λ are investigated within a constituent-quark model and a dynamical coupled-channel formalism. The effects of two new nucleon
resonances and of the K
*(892)- and K1(1270)-exchanges are briefly presented. 相似文献
88.
R. Álvarez-Rodrıguez E. Garrido A. S. Jensen D. V. Fedorov H. O. U. Fynbo 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):303-317
The hyperspherical adiabatic expansion is combined with complex scaling and used to calculate low-lying nuclear resonances
of 12C in the 3α model. We use Ali-Bodmer potentials and compare results for other potentials α-α with similar 8Be properties. A three-body potential is used to adjust the 12C resonance positions to desired values extending the applicability of the method to many-body systems decaying into three
α-particles. For natural choices of three-body potentials we find 14 resonances below the proton separation threshold, i.e. two 0+, three 2+, two 4+, one of each of 1±, 2-, 3±, 4-, and 6+. The partial-wave decomposition of each resonance is calculated as a function of the hyperradius. Strong variation is found
from small to large distance. The connection to previous experimental and theoretical results is discussed and agreements
as well as disagreements are emphasized. 相似文献
89.
T.M. Aliev M. Savcı B.B. Şirvanlı 《The European Physical Journal C - Particles and Fields》2007,52(2):375-382
Double-lepton polarization asymmetries in Λb→Λℓ+ℓ- decay are calculated in the universal extra dimension (UED) model. It is found that numerous double-lepton polarization asymmetries
are very sensitive to the UED model and therefore can be a very useful tool for establishing new physics predicted by the
UED model.
PACS 12.60.-i; 13.30.-a; 14.20.Mr 相似文献
90.
Hasan Kırmızıbekmez Yiğit İnan Rengin Reis Hande Sipahi Ahmet C. Gören Erdem Yeşilada 《Natural product research》2019,33(17):2541-2544
Phytochemical investigations on the EtOH extract of Clematis viticella led to the isolation of six flavonoid glycosides, isoorientin (1), isoorientin 3′-O-methyl ether (2), quercetin 7-O-α-L-rhamnopyranoside (3), quercetin 3,7-di-O-α-L-rhamnopyranoside (4), manghaslin (5) and chrysoeriol 7-O-β-D-glucopyranoside (6), one phenylethanol derivative, hydroxytyrosol (7), along with three phenolic acids, caffeic acid (8), (E)-p-coumaric acid (9) and p-hydroxybenzoic acid (10). The structures of the isolates were elucidated on the basis of NMR and HR-MS data. All compounds were isolated from C. viticella for the first time. Compounds 7 and 8 showed significant anti-inflammatory activity at 100 μM by reducing the release of NO in LPS-stimulated macrophages comparable to positive control indomethacin. Compounds 3 and 7 exhibited anti-inflammatory activity through lowering the levels of TNF-α while 1, 3 and 5 decreased the levels of neopterin better than the positive controls. 相似文献