A Comment on the Higgs
Posted by on Thursday, November 13, 2014 Under: Particle Physics
In the last few days, there have been several news articles in the popular media suggesting that the LHC did not discover the Higgs boson and that what they saw might be something else. This is unlikely to be true, but it has lead to several people asking me for my opinions on the issue. And so for those who have been asking, here is a very brief summary of these claims.
The simplest model of the Higgs boson involves a single particle, relatively heavy compared to other fundamental particles, that behaves as if it is not spinning, and that interacts with other particles proportional to their mass. After more than forty years of searching a particle with these properties was produced and detected at the Large Hadron Collider in Switzerland. I don't think that anyone has any serious doubts that this particle is the Higgs boson.
However nature does not always choose the simplest solution. In the decades that theorists got to play with the Higgs model without experimental data getting in the way, we developed dozens of variations on the Higgs model. For example, there are reasons in supersymmetric theories (which are still only speculative, with no experimental evidence but many theoretical motivations) to expect that there will be at least two Higgs bosons, maybe four. The particle that the LHC detected might be one of two or one of four Higgs bosons, in which case they can expect to find a few more.
Another theory that was developed as an alternative to the Higgs mechanism was technicolour theory. Unfortunately this is too complicated to review in this article (I might write a review of it in future if the demand exists), but I will simply say that there are ways to introduce a new force into the Standard Model of particle physics which provides mass to matter in a different manner than the Higgs boson does. The LHC discovery would appear to remove the need for technicolour theory, but recently it was shown that some of the particles that are used in technicolour could form a bound state that has similar properties to the Higgs boson. If that is true, then what the LHC saw was not a fundamental particle, but rather a system similar to a traditional atom but composed of unknown particles, and which behaves as if it was a Higgs boson.
Both of these alternative to the minimal Higgs model are possible, and can be made to fit with the data. Whether that somewhat remote possibility is worth a headline in major newspapers is a matter for journalism students to debate. Occam's Razor would dictate that they are unnecessary baggage to the Higgs model.
In any case, this spring the LHC is going to start a new run of data collection and one of the focuses will be to further study the properties of the original particle that they discovered. Maybe in a year or two one of the alternative models will be shown to be correct. Maybe it will remain a minimal Higgs boson. Only time will tell.
The simplest model of the Higgs boson involves a single particle, relatively heavy compared to other fundamental particles, that behaves as if it is not spinning, and that interacts with other particles proportional to their mass. After more than forty years of searching a particle with these properties was produced and detected at the Large Hadron Collider in Switzerland. I don't think that anyone has any serious doubts that this particle is the Higgs boson.
However nature does not always choose the simplest solution. In the decades that theorists got to play with the Higgs model without experimental data getting in the way, we developed dozens of variations on the Higgs model. For example, there are reasons in supersymmetric theories (which are still only speculative, with no experimental evidence but many theoretical motivations) to expect that there will be at least two Higgs bosons, maybe four. The particle that the LHC detected might be one of two or one of four Higgs bosons, in which case they can expect to find a few more.
Another theory that was developed as an alternative to the Higgs mechanism was technicolour theory. Unfortunately this is too complicated to review in this article (I might write a review of it in future if the demand exists), but I will simply say that there are ways to introduce a new force into the Standard Model of particle physics which provides mass to matter in a different manner than the Higgs boson does. The LHC discovery would appear to remove the need for technicolour theory, but recently it was shown that some of the particles that are used in technicolour could form a bound state that has similar properties to the Higgs boson. If that is true, then what the LHC saw was not a fundamental particle, but rather a system similar to a traditional atom but composed of unknown particles, and which behaves as if it was a Higgs boson.
Both of these alternative to the minimal Higgs model are possible, and can be made to fit with the data. Whether that somewhat remote possibility is worth a headline in major newspapers is a matter for journalism students to debate. Occam's Razor would dictate that they are unnecessary baggage to the Higgs model.
In any case, this spring the LHC is going to start a new run of data collection and one of the focuses will be to further study the properties of the original particle that they discovered. Maybe in a year or two one of the alternative models will be shown to be correct. Maybe it will remain a minimal Higgs boson. Only time will tell.
In : Particle Physics
I am a theoretical physicist & mathematician, with training in electronics, programming, robotics, and a number of other related fields.
