12 research outputs found
Radiative decay of the as a mixed molecule-charmonium state in effective field theory
Assuming that is a mixture between charmonium and
molecular states with , an analysis of
radiative decays into and is presented. The
modification of the radiative branching ratio due to possible constructive or
destructive interferences between the meson-loop and the short-distance contact
term, which is modeled by a charm quark loop, is shown. The model predictions
are shown to be compatible with the experimentally determined ratio of the
mentioned branching fractions for a wide range of the charmonium
content. In the case of the destructive interference, a strong restriction on
the charmonium admixture is found.Comment: 10 pages, 2 figure
The effects of charmonium on the properties of the hidden charm poles in effective field theory
In this study, the properties of the hidden charm poles are
analyzed under the variation of the bare 2P charmonium mass within the
effective field theory proposed in Ref. \cite{Cincioglu:2016fkm}. The main
focus of the current work is on the pole trajectory of the
charmonium dressed by the meson loops. It is shown that having a
bare charmonium pole above or below the two-meson threshold has radically
different phenomenologies, also depending on how close the pole is to the
threshold.Comment: 16 pages, 2 figure
Quarkonium Contribution to Meson Molecules
Starting from a molecular picture for the X(3872) resonance, this state and its J(PC) = 2(++) heavy-quark spin symmetry partner [X-2(4012)] are analyzed within a model which incorporates possible mixings with 2P charmonium (c (c) over bar) states. Since it is reasonable to expect the bare chi(c1)(2P) to be located above the D (D) over bar* threshold, but relatively close to it, the presence of the charmonium state provides an effective attraction that will contribute to binding the X(3872), but it will not appear in the 2(++) sector. Indeed in the latter sector, the chi(c2)(2P) should provide an effective small repulsion, because it is placed well below the D*(D) over bar* threshold. We show how the 1(++) and 2(++) bare charmonium poles are modified due to the D-(*)(D) over bar ((*)) loop effects, and the first one is moved to the complex plane. The meson loops produce, besides some shifts in the masses of the charmonia, a finite width for the 1(++) dressed charmonium state. On the other hand, X(3872) and X-2(4012) start developing some charmonium content, which is estimated by means of the compositeness Weinberg sum rule. It turns out that in the heavy-quark limit, there is only one coupling between the 2P charmonia and the D-(*)(D) over bar ((*)) pairs. We also show that, for reasonable values of this coupling, leading to X(3872) molecular probabilities of around 70-90%, the X2 resonance destabilizes and disappears from the spectrum, becoming either a virtual state or one being located deep into the complex plane, with decreasing influence in the D*(D) over bar* scattering line. Moreover, we also discuss how around 10-30% charmonium probability in the X(3872) might explain the ratio of radiative decays of this resonance into psi(2S) gamma and J/psi gamma Finally, we qualitatively discuss within this scheme, the hidden bottom flavor sector, paying a special attention to the implications for the X-b and Xb(2) states, heavy-quark spin-flavor partners of the X(3872)
Quarkonium Contribution to Meson Molecules
Starting from a molecular picture for the X(3872) resonance, this state and its heavy-quark spin symmetry partner are analyzed within a model which incorporates possible mixings with 2P charmonium () states. Since it is reasonable to expect the bare to be located above the threshold, but relatively close to it, the presence of the charmonium state provides an effective attraction that will contribute to binding the X(3872), but it will not appear in the sector. Indeed in the latter sector, the should provide an effective small repulsion, because it is placed well below the threshold. We show how the and bare charmonium poles are modified due to the loop effects, and the first one is moved to the complex plane. The meson loops produce, besides some shifts in the masses of the charmonia, a finite width for the dressed charmonium state. On the other hand, X(3872) and start developing some charmonium content, which is estimated by means of the compositeness Weinberg sum rule. It turns out that in the heavy-quark limit, there is only one coupling between the 2P charmonia and the pairs. We also show that, for reasonable values of this coupling, leading to X(3872) molecular probabilities of around 70–90 %, the resonance destabilizes and disappears from the spectrum, becoming either a virtual state or one being located deep into the complex plane, with decreasing influence in the scattering line. Moreover, we also discuss how around 10–30 % charmonium probability in the X(3872) might explain the ratio of radiative decays of this resonance into and . Finally, we qualitatively discuss within this scheme, the hidden bottom flavor sector, paying a special attention to the implications for the and states, heavy-quark spin–flavor partners of the X(3872)