Passage of millicharged particles in the electron beam-dump: Refining constraints from SLACmQ and estimating sensitivity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>NA</mml:mi><mml:mn>64</mml:mn><mml:mi>e</mml:mi></mml:mrow></mml:math>
Physical review. D/Physical review. D.