====== Missing baryons problem ======

Baryons are the sub-atomic particles primarily responsible for an object's mass. They are named after the Greek word // βαρύς //(//barýs//) for 'heavy'. They include protons and neutrons. When cosmologists calculate the amount of baryonic matter which the universe should contain as a consequence of the Big Bang (using the maths of the Standard Model), the result does not correlate with actual cosmological observations.

Roughly half of the baryonic matter which the calculations predict appears to be 'missing'. The so-called 'Missing Baryons Problem'.

Various conclusion have been drawn, all with profound implications for cosmology and particle physics. Either :

1) The maths of the Standard Model is wrong

2) The observations are wrong

3) The missing matter has been altered in some unknown way by some as yet unknown process.

Some research groups are now suggesting that some of the missing baryonic matter is, in fact, observable. See a 2017 paper published in //arXiv// [[https://arxiv.org/abs/1709.10378v2|Missing baryons in the cosmic web revealed by the Sunyaev-Zel'dovich effect]]

//Note:// The 'Missing Baryons Problem' is separate and distinct from the 'missing matter' as implied by [[content:physics:cosmology:dark_matter]]theories.

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Also see : [[content:physics:quantum_physics:proton_mass]]