Study of parton transverse momentum using jets from hadron interactions

We study the momentum unbalance in two-jet events which we have obtained with a two-arm calorimeter array at Fermilab. Although the unbalance is relatively sharply peaked near zero, the rms unbalance is considerably greater than that due to instrumental effects alone. We interpret the unbalance as being principally due to effects of parton transverse momentum $K_T$. We give results for the resolution-corrected rms unbalance (approximately equal to $K_T$) for a range of values of jet $p_T$. $\mathrm{pp}$ collisions are studied at three $s$ values, and ${\pi }^{+}p$ collisions are compared with them at two of these $s$ values. The results are compared with information on $K_T$ obtained from other experiments, principally experiments on dimuon production. Implications of the similarities and of the differences are discussed.