On Zeros of Certain Cusp Forms of Integral Weight for Full Modular Group

We prove that the cusp form Sigma' (c(1)z + d(1))(-(k-sigma)) (c(2)z + d(2))(-sigma) of weight k >= 280 for the full modular group, where the sum is taken over the nonzero pairs of integers (c(j), d(j)) for j = 1, 2 with c(2)d(1) not equal c(1)d(2), and 55/4 < sigma < k/20, has at least left perpendicular k-2 sigma/6 sigma right perpendicular - 2 zeros on the arc A = {e(i theta) vertical bar pi/2 < theta < 2 pi/3}.