TY  - THES
A1  - Berlin, Joshua
T1  - Scalar tetraquark candidates on the lattice
N2  - The topic of this thesis is the investigation of scalar tetraquark candidates from lattice QCD. It is motivated by a previous study originating in the twisted mass collaboration. The initial tetraquark candidate of choice is the $a_0(980)$, an isovector in the nonet of light scalars ($J^P=0^+$). This channel is still poorly understood. It displays an inverted mass hierarchy to what is expected from the conventional quark model and the $a_0(980)$ and $f_0(980)$ feature a surprising mass degeneracy. For this reasons the $a_0(980)$ is a long assumed tetraquark candidate in the literature. 
We follow a methodological approach by studying the sensitivity of the scalar spectrum with fully dynamical quarks to a large basis of two-quark and four-quark creation operators. Ultimately, the candidate has to be identified in the direct vicinity of two two-particles states, which is understandably inevitable for a tetraquark candidate. To succeed in this difficult task two-meson creation operators are essential to employ in this channel. By localized four-quark operators we intend to probe the Hamiltonian on eigenstates with a closely bound four-quark structure.
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/44542
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-445420
N1  - Mathematische Formeln im Abstract, durch $$ gekennzeichnet, werden technisch bedingt nicht korrekt dargestellt.
CY  - Frankfurt am Main
ER  -