Gluon Fusion Contribution to VHjVHj Production at Hadron Colliders

We study the associated production of an electroweak vector boson and the Higgs boson with a jet via gluon-gluon fusion. At the leading order, these processes occur at one-loop level. The amplitudes of these one-loop processes are gauge invariant and finite. Therefore, their contributions towards the corresponding hadronic cross sections and kinematic distributions can be calculated separately. We present results for the Large Hadron Collider and its discussed upgrades. We find that the gluon-gluon one-loop process gives dominant contribution to the $\gamma H j$ production. We observe a destructive interference effect in the $gg\to Z H j$ amplitude. We also find that in the high transverse momentum and central rapidity region, the $ZHj$ production cross section via gluon-gluon fusion becomes comparable to the cross section contributions coming from quark-quark and quark-gluon channels.Comment: 12 pages, 6 figures, 2 tables. Version to appear in PL

Effect of Anomalous Couplings on the Associated Production of a Single Top Quark and a Higgs Boson at the LHC

We consider the production of a single top quark in association with a Higgs boson at the LHC. In particular, we compute the cross sections for the processes $p p \to t h j$, $t h b$, $t h W$, $t h j j$, $t h j b$, $t h W j$, $t h W b$ in the presence of the anomalous $Wtb, WWh$ and $tth$ couplings. We find that the anomalous $Wtb$ and $tth$ couplings can enhance the cross sections significantly. We also analyze a few signatures and show that, if these couplings are indeed anomalous, then with enough data, one should be able to observe the production of the Higgs boson in association with single top quark.Comment: 15 pages, 4 figures, 5 tables. Typos fixed, reference added. Journal versio

Gluon fusion contribution to HBBHBB (B=H,γ,ZB = H,\gamma, Z) at the LHC

We have calculated one-loop amplitudes for the production of Higgs boson in association with two electroweak bosons ($H,\gamma,Z$) via gluon-gluon fusion. We present preliminary results for the total cross section at 8, 13 and 100 TeV center-of-mass energies at $pp$ colliders. We study the interference effect and, also comment on the effect of new physics in terms of anomalous couplings of the Higgs boson in these processes.Comment: Proceedings for QCD@Work 201

Production of a KK-graviton and a Vector Boson in ADD Model via Gluon fusion

In the models with large extra-dimensions, we examine the production of a vector boson (\gamma / Z) in association with the Kaluza-Klein (KK) modes of the graviton via gluon fusion. At the leading order, the process takes place through quark-loop box and triangle diagrams and it is ultraviolate finite. We report the results for the LHC. We also discuss the issues of anomaly and decoupling of heavy quarks in the amplitude.Comment: 12 pages, 8 figures, some references and a note in the appendix adde

ttHttH Anomalous Coupling in Double Higgs Production

We study the effects of top-Higgs anomalous coupling in the production of a pair of Higgs boson via gluon fusion at the Large Hadron Collider (LHC). The introduction of anomalous $ttH$ coupling can alter the hadronic double Higgs boson cross section and can lead to characteristic changes in certain kinematic distributions. We perform a global analysis based on available LHC data on the Higgs to constrain the parameters of $ttH$ anomalous coupling. Possible overlap of the predictions due to anomalous $ttH$ coupling with those due to anomalous trilinear Higgs coupling is also studied. We briefly discuss the effect of the anomalous $ttH$ coupling on the $HZ$ production via gluon fusion which is one of the main backgrounds in the $HH \to \gamma\gamma b {\bar b}$ channel.Comment: 22 pages, 22 figures, 4 tables. Text reorganized, main results unchanged, new plots and references added. Journal versio

Unraveling the CP phase of top-Higgs coupling in associated production at the LHC

We study the sensitivity of top polarization observables to the CP phase $\zeta_t$ in the top Yukawa coupling in the process $pp\to thj$ at the 14 TeV high-luminosity run of the Large Hadron Collider (HL-LHC). We calculate the top polarization in this process as well as an azimuthal asymmetry of the charged lepton arising from the decay of the top in the lab frame. We find that the dependence of this lab-frame azimuthal asymmetry on the phase $\zeta_t$ closely resembles the dependence of the top polarization on $\zeta_t$. As compared to the cross section, which is sensitive to $\zeta_t$ for larger values, the lepton azimuthal asymmetry can provide a sensitive measurement of $\zeta_t$ for smaller values.Comment: 8 pages, 6 figures, Matches Published Version in Phys. Lett.