Different pole structures in line shapes of the X(3872)

The European Physical Journal C, Jun 2017

We introduce a near-threshold parameterization that is more general than the effective-range expansion up to and including the effective range because it can also handle a near-threshold zero in the $D^0\bar{D}^{*0}$ S-wave. In terms of it we analyze the CDF data on inclusive $p\bar{p}$ scattering to $J/\psi \pi ^+\pi ^-$, and the Belle and BaBar data on B decays to $K\, J/\psi \pi ^+\pi ^-$ and $K D\bar{D}^{*0}$ around the $D^0\bar{D}^{*0}$ threshold. It is shown that data can be reproduced with similar quality for X(3872) being a bound and/or a virtual state. We also find that X(3872) might be a higher-order virtual-state pole (double or triplet pole), in the limit in which the small $D^{*0}$ width vanishes. Once the latter is restored the corrections to the pole position are non-analytic and much bigger than the $D^{*0}$ width itself. The X(3872) compositeness coefficient in $D^0\bar{D}^{*0}$ ranges from nearly 0 up to 1 in the different scenarios.

This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1140%2Fepjc%2Fs10052-017-4961-z.pdf

Xian-Wei Kang, J. A. Oller. Different pole structures in line shapes of the X(3872), The European Physical Journal C, 2017, 399, DOI: 10.1140/epjc/s10052-017-4961-z