Yang, Zhi: Prompt Production of Hadronic Molecules and Rescattering of Final States in Heavy Hadron Decays. - Bonn, 2016. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-44400
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-44400,
author = {{Zhi Yang}},
title = {Prompt Production of Hadronic Molecules and Rescattering of Final States in Heavy Hadron Decays},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2016,
month = jul,

note = {The $B$ factories and high energy hadron colliders have accumulated unprecedented data samples in the past decade, and a dramatic progress has been made in hadron spectroscopy. The discovery of many new unexpected states in the open and hidden heavy flavor spectrum is extremely interesting as they can not be simply explained by the conventional quark model, and it triggers a campaign of revealing their internal structure.
It calls for more complex structures. Different explanations for the underlying structure have been proposed, for instance tetraquark, hybrid, hadro-quarkonium and hadronic molecule. The hadrons can form hadronic molecule, just like two nucleons form the deuteron. Especially for the exotic states very close to the threshold of two conventional hadrons, they are very likely to be $S$-wave loosely bound states. The $X(3872)$ is one promising candidate of a hadronic molecule.
To clarify the intriguing properties and finally decipher the internal nature, more accurate data and new processes involving the production and decays of the exotic states will be helpful. In this thesis, we investigated the mechanism for the inclusive prompt production of the exotic state under the molecular scenario. The mechanism is as follows: the constituent mesons would be produced by using the Monte Carlo event generator first, and the formation of the bound state occurs afterward through the final state interaction which can be described by the effective field theory. The well separated energy scales associated in the process make the mechanism valid. And a factorization formula can be obtained by using the Migdal-Watson theorem. We applied this mechanism to predict the production rate of the exotic charm-strange hadrons $D_{sJ}$, the $X(3872)$ and and its bottom analogs and spin partner at hadron colliders.
We also investigated the kinematical effect in the triangle diagram. The effect can play a important role in certain transitions, as it might cause an enhancement or a peak. We thus find the ideal energy range to search for the spin partner of the $X(3872)$ in electron--position collisions associated with one emitted photon. In addition, we studied the hindered $M1$ transition between two bottomia as the kinematical effect in the triangle diagram is expected to lead to partial widths much larger than the prediction of the quark model. Moreover, we studied the motion of the anomalous threshold singularity of the triangle diagram of process $Lambda_bto J/psipi K$ in the complex energy plane. And we found that the intermediate states $Lambda(1890)$, $chi_{c1}$ and $p$ can make the singularity appear at the $chi_{c1}p$ threshold, where the narrow pentaquark-like structure $P_c(4450)$ observed by LHCb is located.},

url = {http://hdl.handle.net/20.500.11811/6859}

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