Conveners
Monday afternoon session 2: Theoretical particle physics
- Rikkert Frederix
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Tomáš Husek (Lund University (SE))22/11/2021, 16:00Regular talk
Within the framework of the massive O($N$) nonlinear sigma model extended to the next-to-leading order in the chiral counting (for $N=3$ corresponding to the two(-quark)-flavor Chiral Perturbation Theory), we calculate the relativistic six-pion scattering amplitude at low energy up to and including terms $\mathcal{O}(p^4)$. Results for the pion mass, decay constant and the four-pion amplitude...
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Mattias Sjö22/11/2021, 16:15Regular talk
We present positivity bounds, derived from the principles of analyticity, unitarity and crossing symmetry, that constrain the low-energy constants of chiral perturbation theory. Bounds are produced for 2, 3 or more flavours with equal meson masses, up to and including next-to-next-to-leading order, using the second and higher derivatives of the amplitude. We enhance the bounds by using the...
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Diogo Buarque Franzosi (Chalmers University of Technology)22/11/2021, 16:30Regular talk
We present a framework to study the interactions among Nambu-Goldstone bosons (NGB), pseudo-NGB (pNGBs) and gauge bosons in Composite Higgs (CH) models at high energies, including operators of order $\mathcal{O}(p^4)$ and $\mathcal{O}(p^2g^2)$ in the chiral expansion and topological terms.
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The set of (p)NGBs comprises the longitudinal modes of electroweak bosons, the Higgs boson, and... -
Malin Sjödahl22/11/2021, 16:45Regular talk
In a few recent papers we introduced the chirality-flow formalism for tree-level scattering processes. This method, which builds on the separate SL(2,C) nature of left- and right-chiral states, makes it possible to directly write down the value of a Feynman diagram as a Lorentz scalar.
In this presentation I will review the method and make outlooks towards tree-level implementations,...
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Jarkko Peuron22/11/2021, 17:00Regular talk
We compute the heavy quark momentum diffusion coefficient during the initial nonequilibrium evolution using QCD effective kinetic theory after an ultrarelativistic heavy-ion collision. We observe that the diffusion coefficient approaches its thermal value during the hydrodynamization process. We also give an introduction to thermalization/hydrodynamization in the weak coupling framework.
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Timea Vitos (Lund University)22/11/2021, 17:15Regular talk
In the colour decomposition approach to treating the SU(3) colour gauge group in automated event generators, the size of the colour matrix grows factorially with the number of external particles in the process. As such, the treatment of the colour degrees of freedom becomes the bottleneck for high-multiplicity QCD processes. We propose to utilize the large-$N_C$ expansion to obtain a sparse...
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Dr Avik Banerjee22/11/2021, 17:30Regular talk
Composite Higgs models together with partial compositeness predict the existence of vector-like top-partners above the TeV scale. A wide class of such models show significant barnching ratio of the top-partners decaying into the third generation quarks and exotic pseudo Goldstone bosons, thus opening up new search topologies at the LHC. We systematically study the exotic decays of the...
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Peter Christiansen (Lund University (SE))22/11/2021, 17:45Regular talk
I am organising the meeting of the Swedish physical society in Lund next year and would like just 5-10 minutes to present it. I hope it can be mixed with partikeldagarna. The theme will be Swedish accelerator based research.
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