Search for pair production of third-generation scalar leptoquarks and top squarks in proton–proton collisions at s=8 TeV

Leptoquark induced rare decay amplitudesh→τ∓μ±andτCheung1, Keung2, Tseng3 2016Phys. Rev. D

“…They put a limit of 685 GeV at 95% CL on m χ [30]. On the other hand, both ATLAS [31] and CMS [32] searched for the third generation LQ with electric charge −2/3 decaying into ab antiquark and a tau lepton (similar to Ω −2/3 in this work), and put a limit of 534 and 740 GeV, respectively.…”

“…That is a very identifiable signature. Both ATLAS [31] and CMS [30,32] collaborations have searched for the third generation leptoquarks via pair production by strong interaction. The CMS have searched for the third generation LQ with electric charged −1/3 (similar to the χ −1/3 of this work) decaying to a top quark and a tau lepton.…”

Fundamental Fermion Interactions via Vector Bosons of Unified SU(2)⊗SU(4) Gauge Fields

“…As free quarks do not exist but immediately hadronize, the result of the X-boson decay will be hadron-lepton pairs which should be directly observable. The search for pair production of third-generation scalar leptoquarks in protonproton collisions at LHC beyond 200 GeV up to 8 TeV has recently been reviewed [23]. There are probably many possible X-boson decay channels, given the multitude of hadrons and leptons of the three generations, and thus the decay signature expected near 35 GeV may in all not be clean and easily discernable.…”

“…We like to stress that the traces of the Q and R matrices vanish, in compliance with the general property of the SU(8) symmetrygroup generators, consisting of the 63 traceless 8 × 8 unitary matrices. Consequently, 3(q + + q − ) + l + + l − = 0, which is obvious from (23). The gray charge brings about a new force (yielding what we may call Quantum Gray-Charge Dynamics, QGD) acting on the fermions, but differs essentially from the electromagnetic (QED) and strong (QCD) forces, which both are mediated by massless vector bosons (photons and gluons) related with the symmetry groups U(1) and SU(3) that is a subgroup of SU(4) considered here.…”

“…Examples of such SM extensions include the above cited GUT models. Leptoquarks can decay, for instance into a pair of quark and lepton, and therefore experimental searches were already suggested to focus on such pair production caused by leptoquarks [23].…”