Let be a field of characteristic zero admitting a biquadratic field extension. We give an example of a torus over whose classifying stack is stably rational and such that in the Grothendieck ring of algebraic stacks over . We also give an example of a finite étale group scheme over such that is stably rational and .
"On the motivic class of an algebraic group." Algebra Number Theory 14 (4) 855 - 866, 2020. https://doi.org/10.2140/ant.2020.14.855