Regular Article - Theoretical Physics
Can the explain the peak associated with Y(4008)?
Institute of Physics, Jan Kochanowski University, ul. Swietokrzyska 15, 25-406, Kielce, Poland
2 Institute for Theoretical Physics, J. W. Goethe University, Max-von-Laue-Str. 1, 60438, Frankfurt, Germany
3 Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Hungarian Academy of Sciences, Budapest, 1525, Hungary
* e-mail: email@example.com
Accepted: 21 January 2019
Published online: 31 January 2019
We study the well-known resonance , corresponding to a charm–anticharm vector state , within a QFT approach, in which the decay channels into DD, , , and are considered. The spectral function shows sizable deviations from a Breit–Wigner shape (an enhancement, mostly generated by loops, occurs); moreover, besides the pole of , a second dynamically generated broad pole at 4 GeV emerges. Naively, it is tempting to identify this new pole with the unconfirmed state Y(4008). Yet, this state was not seen in the reaction , but in processes with in the final state. A detailed study shows a related but different mechanism: a broad peak at 4 GeV in the process appears when loops are considered. Its existence in this reaction is not necessarily connected to the existence of a dynamically generated pole, but the underlying mechanism – the strong coupling of to loops – can generate both of them. Thus, the controversial state Y(4008) may not be a genuine resonance, but a peak generated by the and loops with in the final state.
© The Author(s), 2019