In this work, we study the pi J/psi and (D) over bar* D invariant mass spectra of the Y (4260) decay to find out the origin of the Z(c)(3900) and Z(c)(3885) structures. The pi J/psi - (D) over bar* D interaction is studied in a coupled - channel quasi-potential Bethe - Saltpeter equation approach, and embedded to the Y (4260) decay process to reproduce both pi(-)J/psi and D*-D-0 invariant mass spectra observed at BESIII simultaneously. It is found out that a virtual state at energy about 3870 MeV is produced from the interaction when both invariant mass spectra are comparable with the experiment. The results support that both Z(c)(3900) and Z(c)(3885) have the same origin, that is, a virtual state from pi J/psi (D) over bar* D interaction, in which the (D) over bar* D interaction is more important and the coupling between (D) over bar* D and pi J/psi channels plays a minor role.
A reading of the book of Dirac's life entitled The Strangest Man is a most stirring experience, bringing one back to the beginnings of quantum mechanics where every attempt was made "to establish a basis for theoretical quantum mechanics founded exclusively on relationships between quantities which are in principle observable." The prime movers in this quest were Heisenberg and Dirac. One of Dirac's most important contributions in the passage from classical to quantum mechanics, a passage that consumed much of his early efforts, was unfortunately published in an obscure Russian journal where it remained largely unread until it was found by Feynman while a graduate student at Princeton. The paper posed the question, "what corresponds in the quantum theory to the Lagrangian method of classical mechanics?", a method that, as Dirac pointed out, is clearly superior in the simplicity of its structure to that of the classical Hamiltonian approach. Dirac's partial answer to this question provided the key to solving the problem of introducing the action integral into quantum mechanics that occupied Feynman's mind, leading to his formulation of the path integral technique. His contribution was followed two years later by Schwinger's independently derived statement of the quantum action principle, each contribution providing a complete formulation of quantum mechanics stated in terms of single principle. The present paper points out that the successful introduction of the action principle into quantum mechanics made possible by Dirac, enables one to proceed still further by extending Schwinger's quantum action principle to an open system, to an atom in a molecule. Thus the quantum theory of an atom in a molecule has its roots in the question posed by Dirac in 1933. The paper proposes a return to a greater use of the theorems of quantum mechanics in interpretive chemistry from that begun by Slater in 1933, a staunch advocate of theory following in the footsteps of observation.
In this paper, we study the non-leptonic B-c -> J/psi V and B*(c) -> eta V-c (V =3D rho, K*) weak decays in the framework of QCD factorization. In the evaluation, the form factors are calculated using the Bauer-Stech-Wirbel model and the light-front quark model, respectively. Besides the longitudinal amplitude, the power-suppressed transverse contributions are also evaluated at next-to-leading order. The predictions for the observables of B-c -> J/psi V and B*(c) -> eta V-c decays are presented. We find that the NLO QCD contribution presents about 8% correction to the branching ratios, and the longitudinal polarization fractions of these decays are at the level of ( 80 similar to 90)%. In addition, we suggest direct measurements on some useful ratios, R-K*/rho((lambda=3D0)) and (R) over tilde ((lambda=3D0))(K*/rho), which are very suitable to test the consistence between theoretical prediction and data because their theoretical uncertainties can be well controlled.
In this paper we study the semileptonic decays of B-c(-) -> (eta(c), J/psi)l-(v(1)) over bar. We first evaluate the B-c ->(eta(c), J/Psi) transition form factors F-0(q(2)), F+(q(2)), V(q(2)) and A(0,1,2)(q(2)) by employing the pQCD factorization approach, and then we calculate the branching ratios for all considered semileptonic decays. Based on the numerical results and the phenomenological analysis, we find that: (a) the pQCD predictions for the values of the B-c ->eta(c) and B-c -> J/Psi transition form factors agree well with those obtained by using other methods; (b) the pQCD predictions for the branching ratios of the considered decays are Br (B-c(-)->eta(c)e(-)(v) over bar (mu))) = (4.41(-10.9)(+1.22)) x 10(-3), Br (B-c(-) -> eta(c)tau(-)(v) over bar (tau)) = (1.37(-0.34)(+0.37)) x 10(-3), Br(B-c(-)-> J/Psi e(-)(v) over bar (e)(mu(-)(nu) over bar (mu))=(10.03(-1.18)(+1.33))x10(-3), and Br (B-c(-) -> J/Psi tau(-)(v) over bar (tau)) = (2.92(-0.34)(+0.40)) x 10(-3); and (c) we also define and calculate two ratios of the branching ratios R-eta c and R-J/Psi, which will be tested by LHCb and the forthcoming Super-B experiments.
Gosselin, Thomas
Le Guisquet, Anne-Marie
Brizard, Bruno
Hommet, Caroline
Minier, Frederic
Belzung, Catherine
The C57BL6/J mouse is the most commonly used strain in genetic investigations and behavioural tests. However, only a few studies have used C57BL6/J mice to assess the effects of antidepressant compounds. We carried out a study to compare the behavioural effects of fluoxetine (FLX) in a model of depression in two mice strains: C57BL6/J and BALB/c. We used an 8-week unpredictable chronic mild stress (UCMS) protocol during which FLX was administered (15mg/kg, oral) from the third week to the end of the protocol. We found that UCMS induced degradation of the coat state in the two strains. Moreover, as expected, we observed that FLX elicited antidepressant-like effects in the BALB/c mice by reducing the coat state deterioration and the latency of grooming in splash test. However, in the C57BL6/J mice, it did not induce this action, but instead triggered an opposite effect: an increased sniffing latency in the novelty suppression of feeding test. We conclude that FLX exerts a paradoxical effect in the C57Bl6/J strain. This observation is consistent with some clinical features of hyper-reactivity to FLX observed in humans. Therefore, the UCMS protocol used in C57Bl6/J mice could be a good model to study the mechanisms of the paradoxical effects caused by selective serotonin reuptake inhibitors. Copyright (C) 2017 Wolters Kluwer Health, Inc. All rights reserved.
Abstract I examine positive-parity states of 17 C with J ⩾ 7 / 2 , with emphasis on an earlier shell-model calculation and a recent calculation of a different sort. I find that experimental evidence strongly favors the shell-model results.