Single top quark production in $t$-channel at the LHC in Noncommutative   Space-Time
  We study the production cross section of the $t$-channel single top quark at the LHC in the noncommutative space-time. It is shown that the deviation of the $t$-channel single top cross section from the Standard Model value because of noncommutativity is significant when $|\vec{\theta}| \gtrsim 10^{-4}$ GeV$^{-2}$. Using the present experimental precision in measurement of the $t$-channel cross section, we apply upper limit on the noncommutative parameter. When a single top quark decays, there is a significant amount of angular correlation, in the top quark rest frame between the top spin direction and the direction of the charged lepton momentum from its decay. We study the effect of noncommutativity on the spin correlation and we find that depending on the noncommutative scale, the angular correlation can enhance considerably. Then, we provide limits on the noncommutative scale for various possible relative uncertainties on the spin correlation measurement. 
Seyed Yaser Ayazi, Sina Esmaeili and Mojtaba Mohammadi Najafabadi
hep-ph