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Who ordered that? An unexpected new particle shakes the Standard Model

By Brian Dodson
September 19, 2012
Who ordered that? An unexpected new particle shakes the Standard Model
High-energy particle collision similar to those which may be giving us a glimpse of a new light boson outside the Standard Model (Image: Shutterstock)
High-energy particle collision similar to those which may be giving us a glimpse of a new light boson outside the Standard Model (Image: Shutterstock)
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Schematic presentation of the fundamental particles of the Standard Model of Particle Physics, lacking only the recently discovered Higgs boson (Image: MissMJ)
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Schematic presentation of the fundamental particles of the Standard Model of Particle Physics, lacking only the recently discovered Higgs boson (Image: MissMJ)
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High-energy particle collision similar to those which may be giving us a glimpse of a new light boson outside the Standard Model (Image: Shutterstock)
3/3
High-energy particle collision similar to those which may be giving us a glimpse of a new light boson outside the Standard Model (Image: Shutterstock)
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In the mid-1930s, physicists thought they knew all the subatomic particles of nature – the proton, neutron, and electron of the atom. However, in 1936 the muon was discovered – a new particle having such surprising properties that Nobel laureate I.I. Rabi quipped, "who ordered that?" when informed of the discovery. Evidence that a new light boson may exist has recently been published. Such a boson is not part of the Standard Model (SM) of particle physics. If its existence is confirmed, physicists will confront another "who ordered that?" moment.

The unexpected new light boson, named the E(38) boson for now, is awaiting additional independent verification at present. If so verified, it was discovered at the Nuclotron superconducting particle accelerator at the Joint Institute for Nuclear Research in Dubna, near Moscow. The E(38) appears to have a mass of about 2.5 percent of a proton (38 MeV vs 938 MeV) – lighter than any elementary particle other than neutrinos or electron/positrons. This energy range has been investigated in countless experiments over at least six decades, with few if any previous hints of the existence of a light particle.

The suggestion has been made that the E(38) may not couple electromagnetically. If the E(38) were a stable particle it would be a prime candidate for making up part or all of the cosmological dark matter. However, the E(38) boson is unstable, with a extremely short half-life, so the identity of dark matter is still one of nature's well-kept secrets.

Schematic presentation of the fundamental particles of the Standard Model of Particle Physics, lacking only the recently discovered Higgs boson (Image: MissMJ)
Schematic presentation of the fundamental particles of the Standard Model of Particle Physics, lacking only the recently discovered Higgs boson (Image: MissMJ)

There are an enormous number of particles predicted by the SM – so far with considerable accuracy. There are also a host of composite particles containing two or three quarks. However, within the SM the lightest boson heavier than the electron (0.511 MeV energy) is a pion having a mass of 135 MeV. Further, there appears no source within the SM from whence a new boson with a mass of 38 MeV might appear.

A true physicist is more excited by evidence that cherished ideas are to some degree wrong than by evidence that reconfirms them. Therefore, should the observation and confirmation of the E(38) boson stand the test of time, a search for how to expand or correct the Standard Model will quickly be the research topic du jour in the particle physics community. However, the particle is not yet well enough established to begin risking careers for its sake. The world of science will be waiting for a sign that helps decide which way to jump.

Source: ArXiv

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ScienceDark MatterPhysicsParticle physicsThe Standard ModelElementary particlesBosonsResearch
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Brian Dodson

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mrfixitrick
Particles, smarticles...they are all simply whirling magnetic fields!
Eef van Beveren
You forget to mention the evidence presented in http://arxiv.org/abs/arXiv:1102.1863 , http://arxiv.org/abs/arXiv:1202.1739 and http://arxiv.org/abs/arXiv:1204.3287 .
voluntaryist
mrfixitrick: "... simply whirling magnetic fields!" ? And what is a magnetic field? Not what is does, or looks like, but, What is it? Einstein would have loved to answer that. So would Tesla.
Gregg Eshelman
Still don't know what a magnetic field *is* or how it does what it does.
Take two magnets of equal mass, one permanent, one electromagnetic. Stick them to the underside of a sheet of steel.
The electromagnet stays there only as long as electric energy is running through its coil. The amount of energy needed to hold it against the force of gravity is easy to calculate and easy to know where it comes from. Cut off the energy input and gravity pulls it down.
But what of the permanent magnet? It will stay stuck to the underside of that sheet of steel, defying gravity forever. Where is the energy source? Permanent magnets are "outside the loop" of the formula that defines energy and work. Any inefficiency? The magnet never spontaneously gets warmer, a sure sign of energy being used/converted to another form.
That's part of why so many experimenters work with permanent magnets seeking to discover a "free" source of energy, because a permanent magnet stuck to something where any other object would fall is a "perpetual *motionless* machine". ;-)
Could this new discovery be a key to how the magnetic force works in permanent magnets?
Charles Bosse
Not to rain on anyone's parade, but energy is still conserved by magnets (which, in spite of ICP we really do understand moderately well). If you use magnet A to create magnet B, magnet A gets weaker (and loses some energy to heat). Even just sticking a piece of ferrous material near a magnet causes some loss to heat, and some loss in changing the domains (little magnetic areas in ferrous materials) to stop averaging to zero and start sort of pointing in a similar direction. Eventually all permanent magnets fizzle and align to Earth's background field - eventually can be a very long time for some materials, but it's not long if you pull energy from the magnet or heat it up, no matter how good your magnet is.
If you're clever, you might think that superconductors or other novel materials are a nice way around this. While these materials are interesting, they do not violate conservation of energy - so no such luck.
Ralf Biernacki
@Gregg: NO energy is used by either magnet in clinging to the steel plate, just as no energy is consumed by a chandelier hanging from a ceiling. The reason many people make that error is because our muscles DO consume energy while staying immobile (in the contracted mode). This is just an imperfection of our muscles, and the energy is actually wasted (converted into heat), just like the electrical energy in the electromagnet. If our muscles were like clam muscles, able to "latch" and hold the clamshell closed at no energy cost, we wouldn't be prone to making that error. Likewise, if that electromagnet had current circulating in a closed superconducting coil, it would just hang there with no external power input---which is roughly what the permanent magnet is doing. It only takes work to _move_ an object against resistance; it takes no work to just hold it there.