Squark pair production in the MSSM with explicitCPviolation

Abstract

We analyze effects of the CP-odd soft phases in the MSSM on the pair productions of colored superpartners in pp collisions at the LHC energies. We find that, among all pair-production processes, those of the scalar quarks in the first and second generations are particularly sensitive to the CP-odd phases, more precisely, to the phases of the gluinos and neutralinos. We compute pair-production cross sections, classify various production modes according to their dependencies on the gluino and neutralino phases, perform a detailed numerical analysis to determine individual as well as total cross sections, and give a detailed discussion of 2. electric dipole moment (EDM) bounds. We find that pair productions of first and second generation squarks serve as a viable probe of the CP violation sources in the gaugino sector of the theory even if experiments cannot determine chirality, flavor and electric charge of the squarks produced.

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]. The photon-induced channels are typically more important for the pair production of lighter stops [28], and have a reduced impact on squark-anti-squark [29] and gluino-squark production [30].…”

SUSY parameter determination at the LHC using cross sections and kinematic edges

“…Their impact on the inclusive cross sections summed over all squark species is generically small. However, interference effects between the exchange of electroweak gauge bosons and QCD contributions can become large for the production of two SU(2) doublet squarks pp →q Lq ′ L [41,42]. For SPS1a-type scenarios, the electroweak effects are moderate, but they may be larger for more general models, in particular those without gaugino mass unification.…”

“…Here we suppress the SU(2) quantum numbers of the squarksq = (q L ,q R ) and do not explicitly state the chargeconjugated processes. The squark and gluino production cross sections are known including next-to-leading order (NLO) SUSY-QCD corrections [31][32][33][34], the summation of soft gluon emission [35][36][37][38][39], as well as electroweak contributions and corrections [40][41][42][43][44][45][46]. The strength of the SUSY-QCD interactions and thus the production rate is set by the gauge and the Yukawa couplings of the qqg and qqg interactions, respectively.…”