Model-independent search for T violation with T2HK and DUNE

A bstract We consider the time reversal ( T ) transformation in neutrino oscillations in a model-independent way by comparing the observed transition probabilities at two different baselines at the same neutrino energy. We show that, under modest model assumptions, if the transition probability $$ {P}_{\nu_{\mu}\to {\nu}_e} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>P</mml:mi> <mml:mrow> <mml:msub> <mml:mi>ν</mml:mi> <mml:mi>μ</mml:mi> </mml:msub> <mml:mo>→</mml:mo> <mml:msub> <mml:mi>ν</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:mrow> </mml:msub> </mml:math> around E ν ≃ 0 . 86 GeV measured at DUNE is smaller than the one at T2HK the T symmetry has to be violated. Experimental requirements needed to achieve good sensitivity to this test for T violation are to obtain enough statistics at DUNE for E ν ≲ 1 GeV (around the 2nd oscillation maximum), good energy resolution (better than 10%), and near-detector measurements with a precision of order 1% or better.