Chromo-electroweak interference and parity-violating asymmetries in the production of an electroweak boson + two jets in hadron collisions

Abstract

In the Standard Model the process $q\bar{q}\rightarrow q\bar{q}V$ (where $V=W^\pm,Z^0$ or $\gamma$) can occur via gluon exchange and also via $W^\pm$ or $Z^0$ exchange. The corresponding chromodynamic and electroweak amplitudes can interfere with one another. These interference cross sections are largest when the exchanged $W^\pm$ or $Z^0$ is on-shell when they are also odd under parity. Interference cross sections computed using helicity-amplitude techniques are presented for all interesting subprocesses as well as for the processes $q\bar{q}\rightarrow q\bar{q} l\bar{l}$ in which the lepton pair $l\bar{l}$ comes from the decay of $V$ on-shell. Parity-violating asymmetries are defined and presented at the parton level and for the hadronic processes $pp$ or $p\bar{p}\rightarrow V$ + 2 jets or $l\bar{l}$ + 2 jets. These asymmetries are independent of the polarizations of all particles involved, and do not require that the flavors of the jet partons be measured. They are generally of order 0.01 pb at energies $\sqrt{s} \gtrsim 1$ TeV.