# Prof. Dr. Johannes Henn

## Research focus and highlights

Prof. Dr. Johannes Henn conducts research into scattering amplitudes in quantum field theory, which are used for the precise description of accelerator experiments. The scope of his work is to explore the fundamental building blocks of matter and the laws of nature according to which these interact with each other. Henn is one of the world's leading experts in this innovative research field, which establishes a close link between theoretical and experimental particle physics.

One of the highlights of his research is the discovery of a hidden Yangian symmetry in N=4 supersymmetric Yang-Mills theory [1]. This symmetry explains many simple properties of scattering amplitudes and raises the possibility that this theory could be the first non-trivial quantum field theory in four dimensions that can be solved exactly. Henn notably succeeded in proving the existence of an exact formula for 4 and 5 particle scattering processes in N=4 supersymmetric Yang-Mills theory [2]. Moreover, he demonstrated that bound states based on hidden conformal symmetries, like the Kepler problem (with the conservation of the Runge-Lenz vector) and the hydrogen atom in quantum mechanics, can be solved exactly using this theory [3].

He also developed an innovative method of calculating Feynman integrals [4] based on differential equations. This facilitates greater understanding of the properties of the occurring special functions. This new method has now become standard and is applied in numerous contexts, for example in the phenomenology of elementary particles.

[1] Yangian symmetry of scattering amplitudes in N=4 super Yang-Mills theory

J. M. Drummond, J.M. Henn, J. Plefka

Published in JHEP 0905 (2009) 046

[2] Conformal Ward identities for Wilson loops and a test of the duality with gluon amplitudes

J.M. Drummond, J.M. Henn, G.P. Korchemsky, E. Sokatchev

Nucl.Phys. B826 (2010) 337-364

[3] Solvable Relativistic Hydrogenlike System in Supersymmetric Yang-Mills Theory

S. Caron-Huot and J.M. Henn

Phys. Rev. Lett. 113 (2014) 16, 161601

[4] Multiloop integrals in dimensional regularization made simple

J.M. Henn

Phys. Rev. Lett. 110 (2013) 25, 251601

## Resume

Born in Munich in 1980, he started his scientific career by studying physics at the University of Augsburg, the Université de Savoie and the Ecole Normale Supérieure de Lyon. After earning a doctoral degree at the Laboratoire d'Annecy-Le-Vieux de Physique Théorique, he spent three years doing postdoctoral research at Humboldt University in Berlin.

From there, his career took him to the Institute for Advanced Study in Princeton in 2011. In 2015 he was appointed as a W3 professor at the University of Mainz, where he led a scientific group in theoretical Physics. Since October 2018 he has been a director at the MPI for Physics and a honorary professor at the LMU Munich.

## Scientific awards and charges (selection)

- ERC Consolidator Grant (2017)
- German-French Doctoral College (Coordinator)
- Johannes Gutenberg Fellowship at the JGU Mainz (2015)

## Lectures and Public Relations

- Lectures at doctoral Schools: Wolfersdorf/Deutschland (2010); Perimeter Institute/Kanada (2011); Atrani/Italien (2011); Dubna/Russland (2012); Durham/UK (2013); Stockholm/Sweden (2014); Sao Paulo/Brazilien (2015); Atrani/Italien (2015); Bejing/China (2016); Edinburgh/UK (2017); Oxford/UK (2018)
- Review article Lectures on differential equations for Feynman integrals, J. Phys. A48 (2015) 153001
- Videos of lectures at the NORDITA School on Integrability, August 4-12, 2014
- Scattering Amplitudes in Gauge Theorie Lecture Notes (Springer)
- Article in the IAS Institute Letter Summer 2015: From the Motion of Planets to Quantum Field Theory

## Scientific publications (selection)

- Amplitudes from superconformal Ward identities; D. Chicherin, J.M. Henn, E. Sokatchev; Phys. Rev. Lett. 121 (2018), 02160
- Four-Gluon Scattering at Three Loops, Infrared Structure, and the Regge Limit; J.M. Henn, B. Mistlberger; Phys. Rev. Lett. 117 (2016) 17, 171601
- Analytic form of the two-loop planar five-gluon all-plus-helicity amplitude in QCD; T. Gehrmann, J.M. Henn, N.A. Lo Presti, Phys. Rev. Lett. 116 (2016) 6, 062001
- Three Loop Cusp Anomalous Dimension in QCD; A. Grozin, J.M. Henn, G.P. Korchemsky, P. Marquard; Phys. Rev. Lett. 114 (2015) 6, 062006
- Solvable Relativistic Hydrogenlike System in Supersymmetric Yang-Mills Theory; S. Caron-Huot and J.M. Henn; Phys. Rev. Lett. 113 (2014) 16, 161601
- Multiloop integrals in dimensional regularization made simple; J.M. Henn, Phys. Rev. Lett. 110 (2013) 25, 251601