isoscalar

In particle physics, isoscalar refers to the scalar transformation of a particle or field under the SU(2) group of isospin.{{cite journal |last1=Bracco |first1=A.|author1-link=Angela Bracco |last2=Lanza |first2=E. G. |last3=Tamii |first3=A. |title=Isoscalar and isovector dipole excitations: Nuclear properties from low-lying states and from the isovector giant dipole resonance |journal=Progress in Particle and Nuclear Physics |date=1 May 2019 |volume=106 |pages=360–433 |doi=10.1016/j.ppnp.2019.02.001 |s2cid=127928945 |language=en |issn=0146-6410|doi-access=free |bibcode=2019PrPNP.106..360B |hdl=2434/716331 |hdl-access=free }} Isoscalars are a singlet state, with total isospin 0 and the third component of isospin 0, much like a singlet state in a 2-particle addition of spin. Mesons which have all flavor quantum numbers equal to zero, are known as isoscalars.