Desert (particle physics)

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In the Grand Unified Theory of particle physics, the desert refers to a theorized gap in energy scales, between the TeV scale[clarification needed] and the GUT scale, in which no interactions appear.

It can also be described as a gap in the lengths involved, with no new physics below 10−18 m (the currently probed length scale) and above 10−31 m (the GUT length scale).

The idea of the desert was motivated by the observation of approximate, order of magnitude, gauge coupling unification at the GUT scale.[further explanation needed] Adding interactions at an intermediate scale generically disrupts[why?] the gauge coupling unification.

Standard model particles[edit]

All the Standard Model particles were discovered below the energy scale of approximately 1012 eV or 1 TeV.

The desert[edit]

Above these energies, desert theory predicts no particles will be discovered until reaching the scale of approximately 1025 eV[why?]. According to the theory, measurements of TeV-scale physics at the LHC and the near-future ILC will allow extrapolation all the way up to the GUT scale.

The particle desert's negative implication is that experimental physics will simply have nothing more fundamental to discover, over a very long period of time. Depending on the rate of the increase in experiment energies, this period might be a hundred years or more. Presumably, even if the energy achieved in the LHC, ~ 1013 eV, were increased by up to 12 orders of magnitude, this would only result in producing more copious amounts of the particles known today, with no underlying structure being probed. The aforementioned timespan might be shortened by observing the GUT scale through a radical development in accelerator physics, or by a non-accelerator observational technology, such as examining tremendously high energy cosmic ray events, or another, yet undeveloped technology.

Alternatives to the desert exhibit particles and interactions unfolding with every few orders of magnitude increase in the energy scale.

MSSM Desert[edit]

With the Minimal Supersymmetric Standard Model, adjustment of parameters can make this unification exact[further explanation needed]. This unification is not unique.

Mirror matter desert[edit]

Scenarios like the Katoptron model can also lead to exact unification after a similar energetic desert. If neutrino masses are due to a seesaw mechanism, the seesaw scale should lie within the desert.[why?]

External links[edit]

  • Wolchover, Natalie (9 August 2016). "What No New Particles Means for Physics". Quanta Magazine. Simons Foundation. Retrieved 19 December 2016.