Group introduces six new particles to standard model to solve five enduring problems

February 20, 2017 by Bob Yirka, Phys.org report
Credit: APS/Alan Stonebraker

(Phys.org)—A quartet of researchers has boldly proposed the addition of six new particles to the standard model to explain five enduring problems. In their paper published in the journal Physical Review Letters, Guillermo Ballesteros with Université Paris Saclay, Javier Redondo with Universidad de Zaragoza, Andreas Ringwald with Max-Planck-Institut für Physik and Carlos Tamarit with Durham University describe the six particles they would like to add and why.

The standard theory is, of course, a model that has been developed over the past half-century by physicists to describe how the universe works, and includes such things as the electromagnetic, strong and weak interactions, and also describes what are believed to be the particles that play a role in it all. To date, the theory lists 17 and has stood up against rigorous testing, but it still does not include explanations for what are considered to be some fundamental things.

The researchers are quick to point out that they are not proposing any new physics. Instead, they have assembled what they believe are the most promising theories regarding several problems with the and their possible solutions, and have put them together as an outline of sorts for research moving forward.

The five theories targeted by the research team seek to answer four major questions and to correct a problem with another: What exactly is dark matter, what caused inflation to come about, why is a neutrino so light, and why is there more matter than antimatter? The new model also seeks to correct a theoretical problem regarding asymmetry in the strong force.

The team has named their new model SMASH for "Standard Model Axion See-saw Higgs portal inflation." The proposed are rho (to help explain inflation), the axion (to help explain dark matter) a color triplet fermion and three heavy right-handed neutrinos.

It is still far too early to predict whether the model will be accepted by the physics community, but one thing it has in its favor is that the predictions it makes are clear, which means they can be tested and either proved or disproved. It should be noted that the theory does not include such things as the hierarchy problem or deal with the cosmological constant.

Explore further: Multiple copies of the Standard Model could solve the hierarchy problem

More information: Guillermo Ballesteros et al. Unifying Inflation with the Axion, Dark Matter, Baryogenesis, and the Seesaw Mechanism, Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.118.071802

ABSTRACT
A minimal extension of the Standard Model (SM) providing a complete and consistent picture of particle physics and cosmology up to the Planck scale is presented. We add to the SM three right-handed SM-singlet neutrinos, a new vector-like color triplet fermion and a complex SM singlet scalar σ whose vacuum expectation value at ∼1011 GeV breaks lepton number and a Peccei-Quinn symmetry simultaneously. Primordial inflaton is produced by a combination of σ and the SM Higgs. Baryogenesis proceeds via thermal leptogenesis. At low energies, the model reduces to the SM, augmented by seesaw-generated neutrino masses, plus the axion, which solves the strong CP problem and accounts for the dark matter in the Universe. The model can be probed decisively by the next generation of cosmic microwave background and axion dark matter experiments.

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10 comments

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RNP
4.4 / 5 (7) Feb 20, 2017
Highly speculative, but interesting nonetheless. Open access copy of paper here: https://arxiv.org...5414.pdf

Related, much more detailed paper here: https://arxiv.org...1639.pdf

antialias_physorg
5 / 5 (8) Feb 20, 2017
Highly speculative, but interesting nonetheless.

Well, I think you're allowed to be highly speculative if the theory also makes very definite predictions (which this seems to do).

Weird is not necessarily bad (just weird and untestable - that's a bad combination)
RNP
4.2 / 5 (5) Feb 20, 2017
@antialias_physorg
Agreed. That is part of the reason it is interesting.
Da Schneib
5 / 5 (6) Feb 20, 2017
An interesting and coherent approach. This should get batted around a lot by the people most likely to be able to do something about it, both on the experimental and theoretical sides.

I wouldn't call it all that speculative; it's more a matter of putting together things that have been mooted before into a coherent framework to see which ones work together.
Osiris1
not rated yet Feb 20, 2017
Dark matter now has at least one particle, but how about the corresponding force, 'dark' energy? However this is a start, for now maybe two forces can be selected to cross product into a third force, etc, and lead to measurable dark energy.. If this force appears to counteract the gravitational force, then also it should also counteract the inertial force. The implications would be enormous.
baudrunner
3.7 / 5 (3) Feb 20, 2017
Sorry, if that's the way we are going to be inventing new particles, the entire Standard Model is at risk of losing credibility. Go ahead and point to that trail and tell me that's a photon, and go ahead and select any other of the unnamed trails based on some theory behind its behavior and call it an Axion. I really can't get aboard this one.
baudrunner
1 / 5 (2) Feb 20, 2017
DM and DE are explained by observation of the motions and relative positions of massive bodies in the order of millions of light years distant, producing results that appear to defy prediction. Example - two galaxies, one 10 million light years away and the other 7 million light years away that are 5 million light years apart. According to the accepted dogma, gravity occurs at light speed because Einstein said that nothing, EM waves or objects, could go faster (never mind that he also said, "I may be wrong"). What's wrong with this picture? The positional change of the nearer object is observed three million years ahead of the other's, and their mutual gravitational attraction occurs over a five million light year span. Taking into account this information is logical, and very smart, but the theory is wrong. DE and DM would probably disappear from the page when the understanding that gravity occurs instantaneously is observed.
Elmo_McGillicutty
2.3 / 5 (4) Feb 20, 2017
There are only two particles. All the rest are charge fragments........and only shortly exist when you break a charge.....then dissolve into EM. The only thing in an atom is -e and +e charge. A neutron is a co planar dipole.

All other dipoles are co axial. Such as H1.

Both particles and atoms are mechanical structures.
baudrunner
1 / 5 (2) Feb 21, 2017
The speed of gravity can be calculated by successively plugging very high values for it into the equations that yield D.M. until the D.M. amount reaches zero. Start with 10,000,000 miles per second, say. I think that being fixed on the paradigm that gravity occurs at light speed is just bad for science.
JIMBO
not rated yet Mar 06, 2017
Amid new evidence for Kev DM, this `fix-it' kit seems exciting, but lets face it. The axion has been searched for since the 1970s, & nothing found. Similar to SUSY, which also had a good theoretical justification. Yet SUSY is `Walking the Planck', & many experts predict that it will be shark bait NLT 2018.
The other selling point they make is that it fixes inflation. Inflation remains under a withering attack, & as we know from BICEP2, it too is walking the Planck. If primordial grav waves continue to be unobserved in the next few yrs., inflation will join the ranks of SUSY & be swimming w/the sharks.
This idea is such a patchwork, like nailing single shingles up to fix a leaky roof, that Occam would remove his razor & shred it.

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