Speaker
Prof.
Satyanarayan Nandi
(Oklahoma State University (US))
Description
New physics at the TeV scale is highly anticipated at the LHC. New particles with color, if within the LHC energy reach, will be copiously produced. One such particle is a diquark, having the quantum numbers of two quarks, and can be a scalar or a vector. It will decay to two light quarks, or two top quarks, or a top and a light quark, (up or down type depending on the quantum number of the produced diquark). If singly produced, it can be looked for as a dijet resonance, or as giving extra contribution to the single top production or tt production. In this talk, we consider a diquark having the quantum number of (ud) type, its resonance production, and the subsequent decay to tb, giving rise to excess contribution to the single top production. Even though the diquark mass is large, its strong resonance production dominate the weak production of tb for a wide range of the diquark mass. Also its subsequent decay to tb produce a very hard b-jet compared to the usual electroweak production. In addition, the missing energy in the final state event is much larger from the massive diquark decays. Thus, with suitable cuts, the final state with b, bar{b} and a charged lepton together with large missing energy stands out compared to the Standard Model background. We make a detailed study of both the signal and the background. We find that such a diquark is accessible at the 7 TeV LHC upto a mass of about 3.3 TeV with the luminosity 1 fb^{-1}, while the reach goes up to about 4.3 TeV with a luminosity of 10 fb^{-1}. I will also briefly review the other aspects of diquark production, such as top pair production (tt) and the asociated signal at the LHC.
Summary
Detailed study of top physics at the LHC, and any deviation from the Standard Model expectation can give us hint for new physics. One such possibility is the existence of a diquark state accessible at the LHC energy. Its production leads to significal deviation in the single top and tt productions which can be isolated with suitable cuts on the final state particles. In this talk, I will review the work of our group, as well as other works on the diquark effects on the top physics. Our work is cotained
arXiv:1201.2917v1 [hep-ph] .
Primary author
Prof.
Satyanarayan Nandi
(Oklahoma State University (US))
Co-authors
Mr
Durmus Karabacak
(Oklahoma State University)
Dr
Santosh Rai
(Oklahoma State University)
