# Amplitude methods for effective field theories

**Advisor:** Karol Kampf (IPNP MFF CUNI)

**Funding:** Fully funded

**Contact:** karol.kampf@mff.cuni.cz

The methods of effective field theory are used for theoretical description of particles at low energy sector. New developing field of modern amplitude methods can be applied also for this sector. More particularly it concerns the spinor-helicity formulation of kinematic variables and on-shell recursion relations of amplitudes. It would be nice to find deeper understanding and further extensions of these methods for complete classification of quantum effective field theories. Phd student should study and apply the state-of-the-art methods as duality, the so-called CHY formulation and, last but not least, the geometrical construction applied both for one-particle theories and multiflavour variants.

References

[1] R. Britto, F. Cachazo, B.
Feng and E. Witten, Direct proof of tree-level recursion relation in Yang-Mills
theory, Phys. Rev. Lett. \textbf{94} (2005), 181602 [arXiv:hep-th/0501052
[hep-th]]

[2] H. Elvang and Y. t. Huang, Scattering Amplitudes,
[arXiv:1308.1697 [hep-th]]

[3] C. Cheung, K. Kampf, J. Novotny and J. Trnka,
Effective Field Theories from Soft Limits of Scattering Amplitudes, Phys. Rev.
Lett. \textbf{114} (2015) no.22, 221602 [arXiv:1412.4095 [hep-th]]

[4] C.
Cheung, K. Kampf, J. Novotny, C. H. Shen and J. Trnka, A Periodic Table of
Effective Field Theories, JHEP \textbf{02} (2017), 020 [arXiv:1611.03137
[hep-th]]

[5] C. Cheung, K. Kampf, J. Novotny, C. H. Shen and J. Trnka,
On-Shell Recursion Relations for Effective Field Theories, Phys. Rev. Lett.
\textbf{116} (2016) no.4, 041601 [arXiv:1509.03309 [hep-th]]

[6] J. Bijnens,
K. Kampf and M. Sjo, Higher-order tree-level amplitudes in the nonlinear sigma
model, JHEP \textbf{11} (2019), 074 [arXiv:1909.13684 [hep-th]].