Starts 1 Oct 2026 16:00
Ends 1 Oct 2026 17:00
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HECAP Seminar by Davide Germani - Old Tools for New Puzzles: From Toponium Physics to the Exotic Nature of $X(3872)$
Hybrid
Leonardo Building - Euler Lecture Hall and via Zoom
Abstract
High-precision measurements by the ATLAS and CMS collaborations at the Large Hadron Collider have opened new avenues in heavy quark phenomenology. Interestingly, answering modern questions at the frontier of particle physics often relies on adapting and repurposing well-established theoretical tools developed decades ago. In this seminar, we present two case studies illustrating how contemporary data analysis benefits from classic field-theoretic methods.
In the first part, we review the physics of toponium $t\bar{t}$ near the production threshold, drawing on recent theoretical works by Paolo Nason and collaborators tailored for ATLAS and CMS analyses. We discuss threshold resummation effects, non-perturbative QCD corrections, and how the short lifetime of the top quark dictates the formation and decay dynamics of quasi-bound $t\bar{t}$ states at collider energies.
In the second part, we turn our attention to exotic hadron spectroscopy, focusing on the benchmark state $X(3872)$ and the debate surrounding its interpretation as a compact state versus a loosely bound $D^0 \bar{D}^{*0}$ hadronic molecule. We compare the conventional Flatté parametrization with an Effective Field Theory approach that incorporates an inverted sign in the kinetic term, showing the physical implications of this negative kinetic term and its direct connection to a negative effective range.
Through these examples, this talk emphasizes how emerging anomalies and non-trivial structures in hadron spectroscopy can be systematically resolved by revisiting and building upon established theoretical techniques.
High-precision measurements by the ATLAS and CMS collaborations at the Large Hadron Collider have opened new avenues in heavy quark phenomenology. Interestingly, answering modern questions at the frontier of particle physics often relies on adapting and repurposing well-established theoretical tools developed decades ago. In this seminar, we present two case studies illustrating how contemporary data analysis benefits from classic field-theoretic methods.
In the first part, we review the physics of toponium $t\bar{t}$ near the production threshold, drawing on recent theoretical works by Paolo Nason and collaborators tailored for ATLAS and CMS analyses. We discuss threshold resummation effects, non-perturbative QCD corrections, and how the short lifetime of the top quark dictates the formation and decay dynamics of quasi-bound $t\bar{t}$ states at collider energies.
In the second part, we turn our attention to exotic hadron spectroscopy, focusing on the benchmark state $X(3872)$ and the debate surrounding its interpretation as a compact state versus a loosely bound $D^0 \bar{D}^{*0}$ hadronic molecule. We compare the conventional Flatté parametrization with an Effective Field Theory approach that incorporates an inverted sign in the kinetic term, showing the physical implications of this negative kinetic term and its direct connection to a negative effective range.
Through these examples, this talk emphasizes how emerging anomalies and non-trivial structures in hadron spectroscopy can be systematically resolved by revisiting and building upon established theoretical techniques.