Theory to help experiment make the most of precision measurements

DESY theorist Frank Tackmann wins ERC Consolidator Grant

DESY theorist Frank Tackmann. Image: DESY

Frank Tackmann, researcher in DESY’s theory group, has won one of the prestigious “ERC Consolidator Grants” handed out by the European Research Council (ERC) every year. Tackmann will set up a team of theorists to make precise predictions of a certain kind of collision at the Large Hadron Collider LHC at CERN in Geneva. These will be particularly useful for the coming LHC upgrade that will generate a much higher number of collisions, thus providing the opportunity to study physics phenomena much more precisely.

Starting in summer 2021, the 2-million-Euro-grant will run for five years. Together with three post-docs and three doctoral students, Tackmann will dive deep into the theoretical predictions and, one of the specialties of this working group, combine many of them for the first time. Experimentalists can then exploit these to make even more precise measurements at the LHC.

When protons collide in the LHC, many particles are created in these collisions. These particles interact with each other or decay, creating yet more particles, all within tiny fractions of seconds, until they cannot decay any further. This is called their “final state”. Tackmann’s group will look at a particular “colour-free” type of final state.

Physicists describe the characteristics of particles with a set of attributes, for example charge or mass. Quarks, the constituents of the colliding protons, are characterised by an additional attribute: colour. Quarks are subject to the strong nuclear force and their colour can be red, green or blue. When the colliding quarks happen to have just the right colours, they can produce other particles that have no colour at all. Such colour-free states are for example the Higgs boson or the W and Z particles, carriers of the weak force, or the elusive dark-matter particles, which particle physicists are eager to observe at colliders. And while theoretical predictions for these collisions exist already, Tackmann wants to significantly improve their “theoretical uncertainty” – a parameter that describes the precision of a prediction – which will make his predictions up to 10 times more powerful.

When these predictions are then compared against the experimental measurements with collisions at the LHC, fundamental parameters of particles and forces can be determined at the highest possible precision – and the precise knowledge of these parameters means that any deviations in them might hint at processes that lie beyond the currently known particles and interactions.

The ERC Consolidator Grants are awarded to outstanding researchers with at least seven and up to twelve years of experience after PhD. The funding of up to €2 million per grant is provided for up to five years and mostly covers the employment of researchers and doctoral students to consolidate the grantees' teams.

Frank Tackmann studied theoretical physics at TU Dresden and the University of California at Berkeley, where he obtained his PhD. He went on to work as a postdoctoral researcher at MIT, where he started to lay the groundwork for his predictions. He came to DESY in 2011 as leader of an Emmy Noether research group and has been a permanent staff member since 2015.