Electroweak contributions to squark pair production at the CERN LHC

Abstract

In this paper we compute electroweak contributions to the production of squark pairs at hadron colliders. These include the exchange of electroweak gauge bosons in the s−channel as well as electroweak gaugino exchange in the t− and/or u−channel. In many cases these can interfere with the dominant QCD contributions. As a result, we find sizable contributions to the production of two SU (2) doublet squarks. At the LHC, they amount to 10 to 20% for typical mSUGRA (or CMSSM) scenarios, but in more general scenarios they can vary between −40 and +55%, depending on size and sign of the SU (2) gaugino mass. The electroweak contribution to the total squark pair production rate at the LHC is about 3.5 times smaller.

Squark–anti-squark pair production at the LHC: the electroweak contribution

“…Besides the QCD-based production mechanisms, there are also partonic processes of electroweak origin, like diagonal and non-diagonal squark pair production from qq annihilation [27,28]. They proceed through s-channel photon and Z exchange, and also through neutralino/chargino exchange in the t-channel (ifQ is different fromt), yielding terms of O(α 2 ) and O(α s α).…”

“…They proceed through s-channel photon and Z exchange, and also through neutralino/chargino exchange in the t-channel (ifQ is different fromt), yielding terms of O(α 2 ) and O(α s α). Due to interference between the tree-level QCD and electroweak amplitudes forQ =t, the electroweak contributions can also become sizable, reaching values up to 20% [27].…”

Improved squark and gluino mass limits from searches for supersymmetry at hadron colliders

“…The cross sections for the squark and gluino pair-production processes (1) have been known at next-to-leading order in SUSY-QCD [9][10][11][12] for some time. Electroweak corrections to the O(α 2 s ) tree-level production [19][20][21][22][23] and the electroweak Born production channels of O(αα s ) and O(α 2 ) [24,25] are significant for the pair production of SU(2)-doublet squarksq L and at large invariant masses in general, but they are moderate for total cross sections summed over all squark species.…”

Hadronic production of squark-squark pairs: the electroweak contributions

“…For squark-(anti)-squark production processes, the qq (qq)-channels can rise the LO cross section by up to 20% [24,25]. These contributions have also been studied in the context of non-minimal flavor violation [26] and explicit CP violation [27].…”