Single top production via gluon fusion at CERN LHC

Eilam, Gad
Frank, Mariana
Turan, İsmail
We calculate the one-loop flavor violating top quark decay t -> cgg in the minimal supersymmetric standard model. We discuss the branching ratios obtained with minimal flavor violation, as well as with soft-supersymmetry induced general flavor violation. Based on this rate we calculate the cross section for the single top quark production via gluon fusion, gg -> t (c) over bar, and evaluate its contribution to the cross section for single top quark production in pp collisions at the Large Hadron Collider. We calculate all contributions coming from the standard model and charged Higgs loops, as well as gluino (and neutralino)-up-type squarks, and chargino-down-type squarks loops. Our numerical results show that the gluino and the chargino contributions are largest over the whole parameter range in the unconstrained minimal supersymmetric standard model. While in general the gluino contributions dominate the cross section, this result depends on the supersymmetric flavor violating parameters in the up and down squark sector, the relative mass of the gauginos, and whether or not the grand unified theory relationships between gaugino masses are satisfied. In the most promising scenarios, the pp -> t (c) over bar + (t) over barc + X cross section at the Large Hadron Collider can reach a few hundred fb.


Rare decay of the top t -> cgg in the standard model
Eilam, G; Frank, M; Turan, İsmail (American Physical Society (APS), 2006-03-01)
We calculate the one-loop flavor changing neutral current top quark decay t -> cgg in the standard model. We demonstrate that the rate for t -> cgg exceeds the rate for a single gluon emission t -> cg by about 2 orders of magnitude, while the rate for t -> cq (q) over bar q=u is slightly smaller than for t -> cg.
Rare decay of the top quark t -> cl(l)over-bar and single top quark production at the ILC
Frank, Mariana; Turan, İsmail (American Physical Society (APS), 2006-10-01)
We perform a complete and detailed analysis of the flavor changing neutral current rare top quark decays t -> cl(+)l(-) and t -> c nu(i)(nu) over bar (i) at one-loop level in the standard model, two Higgs doublet models (I and II), and in minimal supersymmetric standard model (MSSM). The branching ratios are very small in all models, O(10(-14)), except for the case of the unconstrained MSSM, where they can reach O(10(-6)) for e(+)e(-), mu(+)mu(-), and nu i (nu) over bari, and O(10(-5)) for tau(+)tau(-). Thi...
Two Higgs doublet model and lepton polarization in the B -> K tau(+)tau(-) decay
Alıyev, Tahmasıb; Savcı, Mustafa; Özpineci, Altuğ (IOP Publishing, 1998-01-01)
The decay width, forward-backward asymmetry and tau lepton longitudinal and transversal polarization for the exclusive B --> K tau(+)tau(-) decay in a two Higgs doubler model are computed. It is shown that the forward-backward asymmetry and longitudinal polarization of the tau lepton are very effective tools for establishing near physics.
t -> cg,c gamma,cZ in the left-right supersymmetric model
Frank, M; Turan, İsmail (American Physical Society (APS), 2005-08-01)
We analyze top-quark flavor violating decays into a charm quark and a gluon, photon, or Z boson in a supersymmetric model incorporating left-right symmetry. We include loop calculations involving contributions from scalar quarks, gluinos, charginos, and neutralinos. We perform the calculations first assuming the minimal (flavor-diagonal) scalar quark scenario and then allowing for arbitrary mixing between the second and the third generation of scalar quarks, in both the up and the down sectors. In each case...
Light vector meson octet-decuplet baryon vertices in QCD
Alıyev, Tahmasıb; Özpineci, Altuğ; Savcı, Mustafa (American Physical Society (APS), 2010-03-01)
The strong coupling constants between light vector mesons and octet-decuplet baryons are calculated in framework of the light cone QCD sum rules, taking into account SU(3) flavor symmetry breaking effects. It is shown that all strong coupling constants can be represented in terms of a single universal function. Size of the SU(3) symmetry breaking effects are estimated.
Citation Formats
G. Eilam, M. Frank, and İ. Turan, “Single top production via gluon fusion at CERN LHC,” PHYSICAL REVIEW D, pp. 0–0, 2006, Accessed: 00, 2020. [Online]. Available: