Editing Extended periodic table (section)

=====Quark matter=====
{{main|Continent of stability|QCD matter}}
It has also been posited that in the region beyond ''A''&nbsp;>&nbsp;300, an entire "[[continent of stability]]" consisting of a hypothetical phase of stable [[quark matter]], comprising freely flowing [[up quark|up]] and [[down quark|down]] quarks rather than [[quark]]s bound into protons and neutrons, may exist. Such a form of matter is theorized to be a ground state of [[baryonic matter]] with a greater binding energy per [[baryon]] than [[nuclear matter]], favoring the decay of nuclear matter beyond this mass threshold into quark matter. If this state of matter exists, it could possibly be synthesized in the same fusion reactions leading to normal superheavy nuclei, and would be stabilized against fission as a consequence of its stronger binding that is enough to overcome Coulomb repulsion.<ref name="udQM">{{cite journal |last1=Holdom |first1=B. |last2=Ren |first2=J. |last3=Zhang |first3=C. |title=Quark matter may not be strange |date=2018 |journal=Physical Review Letters |volume=120 |issue=1 |pages=222001-1–222001-6 <!-- Deny Citation Bot-->|doi=10.1103/PhysRevLett.120.222001|pmid=29906186 |arxiv=1707.06610 |bibcode=2018PhRvL.120v2001H |s2cid=49216916 }}</ref>

Calculations published in 2020<ref name=udQMnew>{{cite journal |last1=Cheng-Jun |first1=Xia |last2=She-Sheng |first2=Xue |last3=Ren-Xin |first3=Xu |last4=Shan-Gui |first4=Zhou |title=Supercritically charged objects and electron-positron pair creation |doi=10.1103/PhysRevD.101.103031 |journal=Physical Review D |year=2020 |volume=101 |issue=10 |pages=103031|arxiv=2001.03531 |bibcode=2020PhRvD.101j3031X |s2cid=210157134 }}</ref> suggest stability of up-down quark matter (udQM) nuggets against conventional nuclei beyond ''A''&nbsp;~&nbsp;266, and also show that udQM nuggets become supercritical earlier (''Z''<sub>cr</sub>&nbsp;~&nbsp;163, ''A''&nbsp;~&nbsp;609) than conventional nuclei (''Z''<sub>cr</sub>&nbsp;~&nbsp;177, ''A''&nbsp;~&nbsp;480).