Matter under the influence of strong and weak interactions
Zusammenfassung der Projektergebnisse
The discovery of the Higgs at the LHC has been a great success for particle physics. With this last ingredient the standard model of particle physics is complete, for now. It is therefore time to fully understand not only the most relevant parts of the standard model, but to have a thorough and complete understanding of it. In the course of this project, the basic underlying theoretical structures of the part of the standard model, which includes the Higgs, have been critically reevaluated. Using massive numerical simulations, it was possible to show that the usual picture of how this part of the standard model operates is too simplistic. In fact, the particles observed, and called the Higgs or W/Z-bosons, do have a subtle, dual structure. This was already anticipated in the early 1980ies, based on an approximate calculations. It was now confirmed. This also helped understanding why and how approximations for this class of theories work. The results furthermore indicate that subtle effects may still be discovered in the standard model, at the LHC. This is an exciting possibility, deserving further study. Even more dramatic may be the consequence for possible extensions of the standard model. Here, rearrangements necessary to satisfy the need for theoretical consistencies could alter the possible experimental signatures. First tentative analyses of these consequences have begun, and promise a wide field of interesting new physics questions. An unexpected side-track of the project has become an important field of study in itself. The starting point of this project were just a subset of standard model particles. Of course, it is necessary to include all, most importantly quarks and leptons, to fully assess the relevance of the findings for the standard model. But there are not (yet) efficient algorithms to include these particle into the numerical simulations performed in this project. While searching for a possibility, a new approach to a completely different problem has been found. The original idea was to slightly modify the weak interaction such that quarks and leptons can be included. This did not work. However, the resulting theory had a completely different virtue. To understand it, it is important to introduce an entirely different topic: The inner structure of neutron stars. These objects are dominated by the strong force. But once more, no efficient algorithm is known how to simulate the situation inside the core of such a star. However, this was possible for the slightly modified theory developed. Moreover, in contrast to other such theories which can be simulated, it contains neutrons, an absolutely necessary ingredient. This theory was called, for technical reasons, G2 -QCD. In a collaboration created in this project, this theory was simulated for the first time. It was shown that it has enough features in common with the real theory governing neutron stars, while at the same time being still tractable. Amazingly, a very rich structure was found at the relevant densities, indicating that theories of this type could induce quite complicated structures in the neutron stars themselves. All of these results lead to many different new research projects, which will be continued afterwards with a multitude of people, and several grant applications. It was therefore an extremely fruitful and productive project, which provided the groundwork for many research projects to follow. Further discussion of many of the results of this project can also be found in the popular science blog of the principal investigator, axelmaas.blogspot.com.
Projektbezogene Publikationen (Auswahl)
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“Bound-state/elementary-particle duality in the Higgs sector and the case for an excited ’Higgs’ within the standard model,” Mod. Phys. Lett. A 28 (2011) 1350103
A. Maas
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“(Non-)Aligned gauges and global gauge symmetry breaking,” Mod. Phys. Lett. A 27 (2012) 1250222
A. Maas
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“The phase diagram of a gauge theory with fermionic baryons,” Phys. Rev. D 86, 111901(R) (2012)
A. Maas, L. von Smekal, B. Wellegehausen, A. Wipf
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“Gauge bosons at zero and finite temperature,” Phys. Rep. 524 (2013) 203
A. Maas
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“Hadron masses and baryonic scales in G2-QCD at finite density” Phys.Rev. D 89 (2014) 056007
B. Wellegehausen, A. Maas, A. Wipf, L. von Smekal
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“Two- and three-point functions in Landau gauge Yang-Mills-Higgs theory” JHEP 1404 (2014) 006
A. Maas, T. Mufti
