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→Observed abundance of lithium: add academic sources for the statements about stellar diffusion/mixing, and rephrase so the description is more detailed. |
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[[Image:SolarSystemAbundances.svg|thumb|center|800px|Abundances of the chemical elements in the Solar System. Hydrogen and helium are most common, residuals within the paradigm of the Big Bang.<ref>{{cite book |last1=Stiavelli |first1=M. |year=2009 |title=From First Light to Reionization the End of the Dark Ages |url=https://books.google.com/books?id=iCLNBElRTS4C&pg=PA8 |page=8 |publisher=[[Wiley-VCH]] |___location=Weinheim, Germany |isbn=9783527627370|bibcode=2009fflr.book.....S }}</ref> Li, Be and B are rare because they are poorly synthesized in the Big Bang and also in stars; the main source of these elements is [[cosmic ray spallation]].]]
Older stars seem to have less lithium than they should, and some younger stars have much more.<ref name="MWoo">{{cite web|title=The Cosmic Explosions That Made the Universe|url=http://www.bbc.com/earth/story/20170220-the-cosmic-explosions-that-made-the-universe|last=Woo|first=M.|date=21 Feb 2017|website=earth|publisher=BBC|url-status=live|archiveurl=https://web.archive.org/web/20170221214442/http://www.bbc.com/earth/story/20170220-the-cosmic-explosions-that-made-the-universe|archivedate=21 February 2017|access-date=21 Feb 2017|quote=A mysterious cosmic factory is producing lithium. Scientists are now getting closer at finding out where it comes from|df=dmy-all}}</ref> One proposed model is that lithium produced during a star's youth sinks beneath the star's atmosphere (where it is obscured from direct observation) due to effects the authors describe as "turbulent mixing" and "diffusion," which are suggested to increase or accumulate as the star ages.<ref>{{Cite journal |last=Richard |first=O. |last2=Michaud |first2=G. |last3=Richer |first3=J. |date=2005-01-20 |title=Implications of WMAP Observations on Li Abundance and Stellar Evolution Models |url=https://doi.org/10.1086/426470 |journal=The Astrophysical Journal |language=en |volume=619 |issue=1 |pages=538–548 |doi=10.1086/426470 |issn=0004-637X}}</ref> Spectroscopic observations of stars in [[NGC 6397]], a metal-poor globular cluster, are consistent with an inverse relation between lithium abundance and age, but a theoretical mechanism for diffusion has not been formalized.<ref>{{Cite journal |last=Korn |first=A. J. |last2=Grundahl |first2=F. |last3=Richard |first3=O. |last4=Barklem |first4=P. S. |last5=Mashonkina |first5=L. |last6=Collet |first6=R. |last7=Piskunov |first7=N. |last8=Gustafsson |first8=B. |date=August 2006
[[File:Nova Centauri 2013 ESO.jpg|thumb|[[Nova Centauri 2013]] is the first in which evidence of lithium has been found.<ref>{{cite web|title=First Detection of Lithium from an Exploding Star|url=http://www.eso.org/public/news/eso1531/|accessdate=29 July 2015|url-status=dead|archiveurl=https://web.archive.org/web/20150801001700/http://www.eso.org/public/news/eso1531/|archivedate=1 August 2015|df=dmy-all}}</ref>]]
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Under the assumptions of all correct calculation, solutions [[beyond the standard model|beyond]] the existing [[Standard Model]] or standard cosmology might be needed.<ref name="fields11" />
Dark matter decay and [[supersymmetry]] provide one possibility, in which decaying dark matter scenarios introduce a rich array of novel processes that can alter light elements during and after BBN, and find the well-motivated origin in supersymmetric cosmologies. With the fully operational [[Large Hadron Collider]] (LHC), much of minimal supersymmetry lies within reach, which would revolutionize particle physics and cosmology if discovered;<ref name="fields11" /> however, results from the ATLAS experiment in 2020 have excluded many supersymmetric models.<ref>{{Cite journal|last=Collaboration|first=Atlas|date=2020-10-27|title=Search for squarks and gluinos in final states with jets and missing transverse momentum using 139 fb$^{-1}$ of $\sqrt{s}$ =13 TeV $pp$ collision data with the ATLAS detector|url=https://arxiv.org/abs/2010.14293v2|language=en|doi=10.1007/JHEP02(2021)143|arxiv=2010.14293 }}</ref>
Changing [[fundamental constants]] can be one possible solution, and it implies that first, atomic transitions in metals residing in high-[[redshift]] regions might behave differently from our own. Additionally, Standard Model couplings and particle masses might vary; third, variation in nuclear physics parameters is needed.<ref name="fields11" />
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