Rashidul Islam

Anomalous Higgs couplings as a window to new physics

The initial data on the production and decay of the Higgs boson reported significant deviations from the Standard Model (SM) expectations, prompting much speculation about its couplings to the other particles. Although the latest data has veered towards conformity with the SM, there is yet room for a sizable deviation from the SM values of the coupling of the Higgs boson with

Probing anomalous couplings using di-Higgs production in electron–proton collisions

t\bar{t}

Investigating perturbative unitarity in the presence of anomalous couplings

, and to a smaller extent, of that with

Double Higgs production at FCC-he and prospects for measurements of self-coupling

W^+W^-

Constraining unparticles from top physics at the Tevatron

and

Scattering unitarity with effective dimension-6 operators

ZZ

Differential cross section for the Higgs boson production in 4-lepton channel and

. Keeping the fluid nature of the data in mind, this opens up an interesting avenue to explore regarding unitarity of gauge boson scattering and the stability of the electroweak vacuum in the presence of anomalous couplings. We show that, for some typical benchmark points, unitarity in gauge boson scattering breaks down between 1 and 10 TeV. We also show that if there are no new light degrees of freedom, the Higgs quartic coupling becomes negative at around the same point, making the electroweak vacuum unstable. Thus, some new ultraviolet completing new physics is demanded at that scale to cancel both these anomalous behaviours if such deviations from the SM couplings are indeed established.

k_T

Abstract A proposed high energy Future Circular Hadron-Electron Collider would provide sufficient energy in a clean environment to probe di-Higgs production. Using this channel we show that the azimuthal angle correlation between the missing transverse energy and the forward jet is a very good probe for the non-standard hhh and h h W W couplings. We give the exclusion limits on these couplings as a function of integrated luminosity at a 95% C.L. using the fiducial cross sections. With appropriate error fitting methodology we find that the Higgs boson self coupling could be measured to be g h h h ( 1 ) = 1.00 − 0.17 ( 0.12 ) + 0.24 ( 0.14 ) of its expected Standard Model value at s = 3.5 ( 5.0 ) TeV for an ultimate 10 ab − 1 of integrated luminosity.

-factorization

We perform a model independent analysis of the helicity amplitudes at high energy for all the

Unitarizing V V Scattering in Light Higgs Scenarios

2\ensuremath{\rightarrow}2