1,975 research outputs found
Puzzles in quarkonium hadronic transitions with two pion emission
The anomalously large rates of some hadronic transitions from quarkonium are
studied using QCD multipole expansion (QCDME) in the framework of a constituent
quark model which has been successful in describing hadronic phenomenology. The
hybrid intermediate states needed in the QCDME method are calculated in a
natural extension of our constituent quark model based on the Quark Confining
String (QCS) scheme. Some of the anomalies are explained due to the presence of
an hybrid state with a mass near the mass of the decaying resonance whereas
other are justified by the presence of molecular components in the wave
function. Some unexpected results are pointed out.Comment: Conference proceedings of the XI Quark Confinement and the Hadron
Spectrum (CONFINEMENT XI). Saint Petersburg (Russia) from 8 to 12 September
201
Partners of the and HQSS breaking
Since the discovery of the the study of heavy meson molecules has
been the subject of many investigations. On the experimental side different
experiments have looked for its spin partners and the bottom analogs. On the
theoretical side different approaches have been used to understand this state.
Some of them are EFT that impose HQSS and so they make predictions for the
partners of the , suggesting the existence of a
partner in the charm sector or or analogs in the
bottom.
In our work, in order to understand the , we use a Chiral quark
model in which, due to the proximity to the threshold, we include states coupled to molecular components. In this coupled channel model
the relative position of the bare states with two meson thresholds
are very important. We have looked for the partners and we don't find
a bound state in the . In the bottom sector we find the
opposite situation where the with is bounded while the
is not bounded. These results shows how the coupling with
states can induced different results than those expected by HQSS. The
reason is that this symmetry is worse in the open heavy meson sector than in
the hidden heavy meson sector.Comment: 6 pages, 4 figures, sent as contribution to the proceedings of the
XVI International Conference on Hadron Spectroscop
Lowest-lying even-parity B ¯ s mesons: heavy-quark spin-flavor symmetry, chiral dynamics, and constituent quark-model bare masses
The discovery of the and resonances in the charmed-strange meson spectra revealed that formerly successful constituent quark models lose predictability in the vicinity of two-meson thresholds. The emergence of non-negligible effects due to meson loops requires an explicit evaluation of the interplay between and Fock components. In contrast to the sector, there is no experimental evidence of bottom–strange states yet. Motivated by recent lattice studies, in this work the heavy-quark partners of the and states are analyzed within a heavy meson chiral unitary scheme. As a novelty, the coupling between the constituent quark-model P-wave scalar and axial mesons and the channels is incorporated employing an effective interaction, consistent with heavy-quark spin symmetry, constrained by the lattice energy levels
Indirect assessment of the fusion properties of choline chloride from solid-liquid equilibria data
The temperature and enthalpy of fusion of choline chloride -[Ch]Cl- are not directly measurable since this compound decomposes upon melting. Yet, given the wide use of this compound in the preparation of deep eutectic solvents (DES), its thermophysical fusion properties are very important for a better understanding of these mixtures and the thermodynamic description of their solid-liquid phase diagrams. In this work, the fusion properties of choline chloride were estimated using the solubility curves of choline chloride in ten different ionic compounds, forming simple binary eutectic mixtures with quasi-ideal liquid phases. Experimental solid-liquid equilibria data for these systems -[Ch] Cl + ionic compounds- were measured, and the ideality of the systems assessed through the quantification of the activity coefficients and their comparison in each pair of binary solutions. The values estimated for the fusion properties of choline chloride are T fus,[Ch]Cl = 597 ± 7 K and Δ fus H [Ch]Cl = 4300 ± 600 J mol −1 . These were additionally checked by thermodynamic consistency tests and by the prediction of the solid-liquid curves with COSMO-RS model. The results obtained with both procedures allow us to guarantee the usefulness and robustness of the estimated data.This work was developed in the scope of the project CICECOAveiro
Institute of Materials, POCI-01-0145-FEDER-007679
(Ref. FCT UID/CTM/50011/2013) and Project POCI-01-0145-FEDER-
006984 e Associate Laboratory LSRE-LCM, both funded by FEDER
through COMPETE2020 - Programa Operacional Competitividade e
Internacionalizaç~ao (POCI) e and by national funds through FCT -
Fundaç~ao para a Ci^encia e a Tecnologia. M.A.R.M acknowledges FCT
for her PhD grant (SFRH/BD/87084/2012). J.O. and L.F. thank the
financing provided by the Spanish Government, Ministerio de
Economia y Competitividad (MINECO), under the project CTQ2012-
37114 and the short-stay grant EEBB-I-16-11792.info:eu-repo/semantics/publishedVersio
Beneficial effects of manually assisted chiropractic adjusting instrument in a rabbit model of osteoarthritis.
Osteoarthritis (OA) is a degenerative disease characterized by injury of all joint tissues. Our previous study showed that in experimental osteoporosis, chiropractic manipulation (CM) exerts protective effects on bone. We here assessed whether CM might ameliorate OA by improving subchondral bone sclerosis, cartilage integrity and synovitis. Male New-Zealand rabbits underwent knee surgery to induce OA by anterior cruciate ligament injury. CM was performed using the chiropractic instrument ActivatorV 3 times/week for 8 weeks as follows: force 2 setting was applied to the tibial tubercle of the rabbit right hind limb (TM-OA), whereas the corresponding left hind limb received a false manipulation (FM-OA) consisting of ActivatorV firing in the air and slightly touching the tibial tubercle. After sacrifice, subchondral bone integrity was assessed in the tibiae by microCT and histology. Cartilage damage and synovitis were estimated by Mankin's and Krenn's scores, respectively, and histological techniques. Bone mineral density and content in both cortical and trabecular compartments of subchondral bone decreased in OA rabbits compared to controls, but partially reversed in the TM-OA group. Trabecular bone parameters in the latter group also showed a significant improvement compared to FM-OA group. Moreover RANKL, OPG, ALP and TRAP protein expression in subchondral bone significantly decreased in TM-OA rabbits with respect to FM-OA group. CM was associated with lower Mankin's and Krenn's scores and macrophage infiltrate together with a decreased protein expression of pro-inflammatory, fibrotic and angiogenic factors, in TM-OA rabbits with respect to FM-OA. Our results suggest that CM may mitigate OA progression by improving subchondral bone as well as cartilage and synovial membrane status.AODM was supported by grants from the Spanish Chiropractic Association (AEQ). AM was supported by grants from Spanish Ministry of Economy and Competitiveness and Carlos III Institute of Health (CP15/00053 and PI16/00991). We thank Dr. Carlos Guillén-Viejo (School of Pharmacy, Universidad Complutense de Madrid) for his help in advising in molecular biology methods. The authors are also grateful to Mark S. Davis for his assistance with editing and proofreading the article.S
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