Scattering Amplitudes: from Geometry to Experiment

Project Information

SAGEX

Grant agreement ID: 764850

DOI

10.3030/764850

Project closed

EC signature date 18 May 2018

Start date 1 September 2018

End date 31 August 2022

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 3 983 215,68

EU contribution

€ 3 983 215,68

Coordinated by

QUEEN MARY UNIVERSITY OF LONDON
United Kingdom

Periodic Reporting for period 2 - SAGEX (Scattering Amplitudes: from Geometry to Experiment)

Reporting period: 2020-09-01 to 2022-08-31

Summary of the context and overall objectives of the project

Scattering Amplitudes: from Geometry to Experiment (SAGEX) was a EU Horizon 2020 Marie Skłodowska-Curie Action (MSCA) Innovative Training Network (ITN), funded from 01 September 2018 to 31 August 2022. The network comprised 8 Beneficiaries (7 academic and 1 non-academic), plus 15 academic and industrial Partner Organisations. It trained 15 outstanding Early Stage Researchers (ESRs) in the field of scattering amplitudes, providing cross-sectoral training via industry and academic secondments, as well as local and network-wide events.

Scattering amplitudes describe the interactions between the fundamental particles that make up the world around us – the building blocks of all matter, from atoms to stars. Remarkably, they also describe the interactions of extraordinarily large objects, such as black holes. Advances in our theoretical understanding of scattering amplitudes have huge practical benefits: they enable more precise predictions at particle colliders such as the Large Hadron Collider (LHC), which allow better experimental measurements and searches for new particles; and allow us to push the precision frontier in gravitational wave studies at current experimental facilities such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo interferometer. In turn, these experiments lead the way in developing cutting-edge electronics and computing methods, which have considerable benefits for society as a whole. For the first time, we assembled a focussed team that unites researchers from all corners of the research field, with a common objective to make a step-change in the level of theoretical predictions that are possible.

The research work was structured across three frontiers:

• Geometry (leveraging beautiful and intriguing structures and patterns that have recently been revealed, which suggest that our fundamental understanding of scattering amplitudes is not yet complete).
• Loops (pushing theoretical predictions to the highest possible level of detail).
• Lab (applying the techniques developed above to real-life experiments such as the LHC).

Each ESR developed technical breadth across the entire scattering amplitudes field, whilst gaining in-depth knowledge and skills in their own area of speciality. Additionally, they were trained in a range of transferable skills, and interacted closely with our industrial Partner Organisations to further enhance their future career potential.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Fifteen exceptional ESRs were recruited and enrolled on a PhD programme at their host Beneficiary. During the programme, the ESRs published 49 papers in peer-reviewed journals and a further 14 publications are available as pre-prints (to be submitted to peer-reviewed journals), contributing to our three scientific work packages (Geometry, Loops and Lab). These publications are all open access and can be found via the SAGEX website. They detail the progress and research of the ESRs beyond the state of the art. In addition to the originally planned work packages, SAGEX researchers have adapted techniques for scattering amplitudes to the study of gravitational waves, with renewed impetus following their discovery in 2016, which has resulted in five ESRs working on these important new topics.

All 15 ESRs were provided with excellent 3-month secondment opportunities with one of our industry Partners, who in turn benefitted from the ESR’s expertise within their organisations. The ESRs experienced a bespoke scientific and soft-skills curriculum taking them from master’s level to the cutting edge of scattering amplitudes research. This curriculum has been made available to the field via the SAGEX website (www.sagex.org) as a gold-standard training programme.

In the final two years of the programme, the following training events were held:

• SAGEX Mathematica & Maple School (remote) hosted by CEA-Saclay in January 2021. Lectures were given on the Mathematica and Maple packages.
• European Study Group with Industry 165 (remote) hosted by Durham University. The ESRs worked with other researchers to solve problems posed by Industry.
• SAGEX PhD School in Amplitudes 2021 (remote) hosted by University of Copenhagen. This School, run by the ESRs covered the areas: Amplituhedron and positive geometries, Celestial amplitudes, Post-Minkowskian gravity from scattering amplitudes and QCD phenomenology and scattering amplitudes.

The school lectures were video-recorded for the benefit of the wider community and are available on the SAGEX YouTube channel.

Together with our Partner Organisation, EE Films, the ESRs created a film about their experiences in the network, 'Doing a PhD in Physics' (https://www.youtube.com/watch?v=ZbV0YnzeTzQ). Combining self-recorded video diaries, the film documents their successes, challenges and the common themes uniting their experiences. Working with another Partner Organisation, Milde Marketing Science Communications, the ESRs designed an online outreach exhibition 'SAGEX – at the Frontier of Physics,' (www.exhibition.sagex.org) which launched in early 2022. In addition, many took part in local outreach events at their institutes.

The SAGEX website (www.sagex.org) is a useful resource, with details of the network members, events, publications, a twitter feed and blog. We also built a community repository (www.amplitudes.org) where researchers across the entire field of scattering amplitudes can share code and other research materials.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

All of the ESRs published their research in high-impact, peer-reviewed journals, and their scientific progress has been significant. Their work has provided a deeper understanding of all three areas under study, from the more mathematical aspects of scattering amplitudes to applications to phenomenology and gravitational waves.

It is testament to the SAGEX programme that 12 of the 15 ESRs have secured post-doctoral positions at highly regarded academic Institutions, two have secured positions in the private sector, while the remaining ESR started his fellowship late and is completing his PhD thesis. They have achieved the goal to emerge from SAGEX equipped to be the next generation of world-leaders in academia, industry or the public sector.

More widely, lecture recordings from our curriculum have been made freely available to the scientific community, benefitting many more doctoral and post-doctoral students in Europe and beyond. Our SAGEX Review on Scattering Amplitudes (arXiv:2203.13011) provides an overview of the field, from basic aspects to a selection of current (2022) research and developments. Together with our www.amplitudes.org repository, we support the priorities of the European Research Area, by ‘optimising exchange and transfer of and access to scientific findings’ in the field of scattering amplitudes.

The film and online exhibition produced by the ESRs brings the world of scattering amplitudes to the public, and is a lasting legacy of the programme that will be available for years to come.

A visual representation of the amplituhedron

SAGEX logo

SAGEX network group photograph November 2019

SAGEX network group photograph June 2022