Constraining Unparticles from Top Physics at TeVatron

Abstract

We study and analyze the recent observations of the top pair production $σ(p\bar p\to t \bar t)$ at TeVatron through flavor conserving and flavor violating channels ${\it via}$ vector and tensor unparticles. The unparticle sector is considered with the possibility of being a color singlet or octet. The modified unparticle propagator is used to investigate the contribution of these unparticles to the observed $A_{FB}^{t\bar t}$ (forward backward asymmetry in top pair production) and the spin correlation at TeVatron. We have also studied the impact of the flavor violating couplings of unparticles to the third generation quarks on (a) pair production of same sign tops/antitops $σ(p\bar p\to tt+\bar t \bar t)$ at TeVatron and (b) the partial top decay width for $Γ_{\cal U}(t\to u\,{\cal U}^V)$. We find that a large region of parameter space is consistent with the measurements of \tt production cross-section, \afbt and spin correlation coefficient at TeVatron and observe that the top decay width measurement constrains the flavor violating coupling of vector unparticles more severely than the same sign top/antitop production at TeVatron. We also predict the best point-set in the model parameter space for specific choices of \du corresponding to $χ^2_{\rm min}$ evaluated using the \mttb spectrum of \afbt from the data set of Run II of TeVatron at the integrated luminosity 8.7 fb$^{-1}$. Our results and analysis are consistent even with unparticle theories having broken scale invariance as long as the infrared cut-off scale is much less than the top pair production threshold.