Gamermann, D., Nieves, J., Oset, E., & Ruiz Arriola, E. (2010). Couplings in coupled channels versus wave functions: Application to the X(3872) resonance. Phys. Rev. D, 81(1), 014029–14pp.
Abstract: We perform an analytical study of the scattering matrix and bound states in problems with many physical coupled channels. We establish the relationship of the couplings of the states to the different channels, obtained from the residues of the scattering matrix at the poles, with the wave functions for the different channels. The couplings basically reflect the value of the wave functions around the origin in coordinate space. In the concrete case of the X(3872) resonance, understood as a bound state of D-0(D) over bar*(0) and D+D*(-) (and c.c. From now on, when we refer to D-0(D) over bar*(0), D+D*(-), or D (D) over bar* we are actually referring to the combination of these states with their complex conjugate in order to form a state with positive C-parity), with the D-0(D) over bar*(0) loosely bound, we find that the couplings to the two channels are essentially equal leading to a state of good isospin I = 0 character. This is in spite of having a probability for finding the D-0(D) over bar*(0) state much larger than for D+D*(-) since the loosely bound channel extends further in space. The analytical results, obtained with exact solutions of the Schrodinger equation for the wave functions, can be useful in general to interpret results found numerically in the study of problems with unitary coupled channels methods.
|
Molina, R., Branz, T., & Oset, E. (2010). New interpretation for the D*(s2)(2573) and the prediction of novel exotic charmed mesons. Phys. Rev. D, 82(1), 014010–17pp.
Abstract: In this manuscript we study the vector-vector interaction within the hidden-gauge formalism in a coupled channel unitary approach. In the sector C = 1, S = 1, J = 2 we get a pole in the T matrix around 2572 MeV that we identify with the D*(s2)(2573), coupling strongly to the D*K*(D-s(*)phi(omega)) channels. In addition we obtain resonances in other exotic sectors which have not been studied before such as C = 1, S = -1, C = 2, S = 0 and C = 2, S = 1. These "flavor-exotic'' states are interpreted as D*(K) over bar*, D*D*, and (DsD)-D-** molecular states but have not been observed yet. In total we obtain nine states with different spin, isospin, charm, and strangeness of non-C = 0, S = 0 and C = 1, S = 0 character, which have been reported before.
|
Yamagata-Sekihara, J., Nieves, J., & Oset, E. (2011). Couplings in coupled channels versus wave functions in the case of resonances: Application to the two A(1405) states. Phys. Rev. D, 83(1), 014003–15pp.
Abstract: In this paper we develop a formalism to evaluate wave functions in momentum and coordinate space for the resonant states dynamically generated in a unitary coupled channel approach. The on-shell approach for the scattering matrix, commonly used, is also obtained in quantum mechanics with a separable potential, which allows one to write wave functions in a trivial way. We develop useful relationships among the couplings of the dynamically generated resonances to the different channels and the wave functions at the origin. The formalism provides an intuitive picture of the resonances in the coupled channel approach, as bound states of one bound channel, which decays into open ones. It also provides an insight and practical rules for evaluating couplings of the resonances to external sources and how to deal with final state interaction in production processes. As an application of the formalism we evaluate the wave functions of the two A(1405) states in the pi Sigma, (K) over barN, and other coupled channels. It also offers a practical way to study three-body systems when two of them cluster into a resonance.
|
Branz, T., Geng, L. S., & Oset, E. (2010). Two-photon and one-photon-one-vector meson decay widths of the f(0)(1370), f(2)(1270), f(0)(1710), f(2)'(1525), and K-2*(1430). Phys. Rev. D, 81(5), 054037–10pp.
Abstract: We calculate the radiative decay widths, two-photon (gamma gamma) and one-photon-one-vector meson (V gamma), of the dynamically generated resonances from vector-meson -vector-meson interaction in a unitary approach based on the hidden-gauge Lagrangians. In the present paper we consider the following dynamically generated resonances: f(0)(1370), f(0)(1710), f(2)(1270), f(2)'(1525) K-2*(1430), two strangeness 0 and isospin 1 states, and two strangeness 1 and isospin 1= 2 states. For the f(0)(1370) and f(2)(1270) we reproduce the previous results for the two-photon decay widths and further calculate their one-photon -one-vector decay widths. For the f(0)(1710) and f(2)'(1525) the calculated two-photon decay widths are found to be consistent with data. The rho 0 gamma, omega gamma and phi gamma decay widths of the f0(1370), f(2)'(1270) f(0)(1710), f(2)'(1525) are compared with the results predicted by other approaches. The K*(+)gamma and K*(0)gamma decay rates of the K-2*(1430) are also calculated and compared with the results obtained in the framework of the covariant oscillator quark model. The results for the two states with strangeness 0, isospin 1 and two states with strangeness 1, isospin 1/ 2 are predictions that need to be tested by future experiments.
|
Molina, R., Nagahiro, H., Hosaka, A., & Oset, E. (2011). Decay of vector-vector resonances into gamma and a pseudoscalar meson. Phys. Rev. D, 83(9), 094030–12pp.
Abstract: We study the decay of dynamically generated resonances from the interaction of two vectors into a gamma and a pseudoscalar meson. The dynamics requires anomalous terms involving vertices with two vectors and a pseudoscalar, which renders it special. We compare our result with data on K-2*(+) (1430) -> K+ gamma and K-2*(0) (1430) -> K-0 gamma and find a good agreement with the data for the K-2*(+) (1430) case and a width considerably smaller than the upper bound measured for the K-2*(0) (1430) meson. We also investigate the decay into pi(+) gamma of one a(2) state, tentatively associated to the a(2)(1320), obtaining qualitative agreement with data.
|
