June 03, 2014
Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)
Hitoshi Murayama, Director of the Kavli IPMU, and Dr. Kohsaku Tobioka, a postdoctoral fellow at KEK who had worked at Kavli IPMU until March 31, 2014 and the other researchers have successfully found a breakthrough solution to this puzzling phenomenon. They resolved the tension between the Higgs mass observed at CERN in 2012 and its theoretically expected value in supersymmetry (SUSY), while keeping the naturalness of the theory. Their article was published in the Physical Review Letters and further selected as an "Editor's Suggestion," the most interesting and important results among recently published articles.
The Standard Model has several problems, although it successfully describes the behavior of elementary particles. Supersymmetry (SUSY) is one of the most popular theories that can resolve certain issues in the Standard Model. However, the Higgs mass observed at CERN was larger than the one expected in the minimal model of SUSY. To solve this tension, there have been various SUSY models proposed with different extensions. The problem is that these models become unnatural when we employ a large "SUSY breaking" value which is required to explain the observed Higgs mass.
In this article, the authors presented a SUSY model with two Dirac-type particles, where naturalness was not affected, even when the SUSY breaking was large. For this mechanism, the observed Higgs mass is explained in SUSY, while naturalness is maintained.
According to Director Murayama, "Matter is thought to be composed of two types of particles. One is Dirac particles, which have distinction between matter and anti-matter particles like electrons and positrons. The other is Majorana particles, whose matter and anti-matter cannot be distinguished. The previous SUSY models have usually employed Majorana particles. Instead, we tried to use the Dirac-type SUSY particles, and unexpectedly succeeded in constructing the beautiful model."
This result could trigger further development of new SUSY models, and in the future, the International Linear Collider (ILC) is expected to be able to see signals of their model.
Published paper (Publication date: May 14, 2014)
- Neutral Higgs Mass in Supersymmetry from Non-decoupling Effects
Physical Review Letters 112, 191803 (2014)
DOI: 10.1103/PhysRevLett.112.191803
Links
PIO Contact:
Marina Komori, Kavli Institute for the Physics and Mathematics of the Universe, The University of Tokyo
Email：press_at_ipmu.jp