arXiv subjects

Taras V. Zagoskin

Publications and source records attributed to Taras V. Zagoskin.

3 recordsLinked to original sources

arXiv2018

Higgs boson $ZZ$ couplings in Higgs-strahlung at the ILC

We derive the fully differential cross section of the Higgs-strahlung process $f \bar{f} \to Z \to Z (\to f_Z \bar{f}_Z) X (\to f_X \bar{f}_X)$, where $f$, $f_Z$, and $f_X$ are arbitrary fermions and $X$ is a spin-zero particle with arbitrary couplings to $Z$ bosons and fermions. This process with $f = e$ and $X = h$ ($h$ denotes the Higgs boson) is planned to be measured at the ILC to put constraints on the couplings $g_1$, $g_2$, $g_3$ of the Higgs boson to $Z$ bosons. Using the obtained fully differential cross section, we define observables measurement of which yields the tightest constraints on the couplings. Explicit dependences of these observables on $g_i$ are derived.

hep-ph↗

arXiv2018

The Higgs boson decay into ZZ decaying to identical fermion pairs

In order to investigate various decay channels of the Higgs boson $h$ or the hypothetical dilaton, we consider a neutral particle $X$ with zero spin and arbitrary $CP$ parity. This particle can decay into two off-mass-shell $Z$ bosons ($Z_1^*$ and $Z_2^*$) decaying to identical fermion-antifermion pairs ($f \bar{f}$): $X \to Z_1^* Z_2^* \to f \bar{f} f \bar{f}$. We derive analytical formulas for the fully differential width of this decay and for the fully differential width of $h \to Z_1^* Z_2^* \to 4 \ell$ ($4 \ell$ stands for $4 e$, $4 μ$, or $2 e 2 μ$). Integration of these formulas yields some Standard Model histogram distributions of the decay $h \to Z_1^* Z_2^* \to 4 \ell$, which are compared with corresponding Monte Carlo simulated distributions obtained by ATLAS and with ATLAS experimental data.

hep-ph↗

arXiv2015

Decays of a neutral particle with zero spin and arbitrary CP parity into two off-mass-shell Z bosons

Effects are investigated of CP symmetry violation in the decay of a scalar particle X (the Higgs boson) into two off-mass-shell Z bosons both decaying into a fermion-antifermion pair, $X \to Z_1^* \, Z_2^* \to f_1 \bar{f_1} \, f_2 \bar{f_2}$. The most general form of the amplitude of the transition $X \to Z_1^* Z_2^*$, wherein the boson X may not have definite CP parity, is considered. Limits of applicability of the narrow-Z-width approximation used when obtaining differential widths of the decay under consideration are determined. Various observables connected with the structure of the amplitude of the decay $X \to Z_1^* Z_2^*$ are studied. These observables are analyzed in the Standard Model, as well as in models conceding indefinite CP parity of the Higgs boson. An experimental measurement at the LHC of angular and invariant mass distributions of the decay $X \to Z_1^* Z_2^* \to f_1 \bar{f_1} f_2 \bar{f_2}$ can give information about the CP properties of the Higgs boson and its interaction with the Z boson.

hep-ph↗