相关论文: SANCnews: Sector ffbb
In this paper we describe the implementation of the processes f_1 bar-f_1 H A --> 0 into the framework of SANC system. Here A stands for a photon and f_1 -- for a massless fermion whose mass is neglected everywhere besides arguments of…
In this paper we present the results of the implementation of the decay t -> b f1 f1 into the SANC system (f1 is a massless fermion). The new aspect of the work is the combination of QCD and EW corrections. All calculations are done at the…
The implementation of the process $\gamma\gamma \to ZZ$ at the one-loop level within {\tt SANC} system multi-channel approach is considered. The derived one-loop scalar form factors can be used for any cross channel after an appropriate…
In this paper we describe the implementation of the SM process $\gamma\gamma\to\gamma\gamma$ through a fermion and boson loops into the framework of SANC system. The computations of this process takes into account non-zero mass of loop…
In this paper we describe the implementation of the QED process $\gamma\gamma\to\gamma\gamma$ through a fermion loop into the framework of SANC system. The computations of this process takes into account non-zero mass of loop-fermion. We…
The scale of fermion mass generation can, as shown by Appelquist and Chanowitz, be bounded from above by relating it to the scale of unitarity violation in the helicity nonconserving amplitude for fermion-anti-fermion pairs to scatter into…
We study 1D fermions with photoassociation or with a narrow Fano-Feshbach resonance described by the Boson-Fermion resonance model. Using thebosonization technique, we derive a low-energy Hamiltonian of the system. We show that at low…
The most general basis of operators parametrizing a low-scale departure from the SM particle content is constructed. The SM gauge invariance is enforced, and operators of lowest dimensions are retained separately for a new light neutral…
We investigate a bilayer honeycomb lattice model of spin-1/2 fermions at half-filling with local Heisenberg coupling of fermion spins across the two layers. Using variational Monte Carlo (VMC) simulation, we demonstrate that the system…
We study the transition form factors between pseudoscalar and vector mesons using a covariant fermion field theory model in $(3+1)$ dimensions. Performing the light-front calculation in the $q^+ =0$ frame in parallel with the manifestly…
We analyze a new class of FCNC processes, the $f \to f^{\prime} \, \bar{\gamma}$ decays of a fermion $f$ into a lighter (same-charge) fermion $f^{\prime}$ plus a {\it massless} neutral vector boson, a {\it dark photon} $\bar{\gamma}$. A…
PROPHECY4f is a Monte Carlo event generator for precise simulations of the Higgs-boson decay H -> WW/ZZ -> 4fermions, supporting leptonic, semileptonic, and four-quark final states. Both electroweak and QCD corrections are included.…
We consider the $D4-D8-\bar{D8}$ brane system which serves as ultraviolet completion of the Nambu-Jona-Lasinio model, where the only degrees of freedom carrying baryon charge are fermions. By turning on chemical potential for this charge…
The Holstein model of spinless fermions interacting with dispersionless phonons in one dimension is studied by a Green's function Monte Carlo technique. The ground state energy, first fermionic excited state, density wave correlations, and…
The unitarity limit describes interacting particles where the range of the interaction is zero and the scattering length is infinite. We present precision benchmark calculations for two-component fermions at unitarity using three different…
The Standard Model contributions to the processes $\gamma \gamma \to \gamma \gamma$, $\gamma Z$ and ZZ at sufficiently high energies, are found to be helicity conserving and almost purely imaginary. This is due to the W-loop contribution,…
A computer program ee4fgamma for calculating cross sections of any four fermion final state of e+e--annihilation at high energy and the corresponding bremsstrahlung reaction that is possible in the framework of the Standard Model is…
We present a scheme for integrating the matrix element of an arbitrary e^+e^-\to f_1f_2\bar f_3\bar f_4 process over the complete four-fermion phase space, or its any part, by means of the Monte Carlo technique. The presented algorithm has…
We present a quantum Monte Carlo method which allows calculations on many-fermion systems at finite temperatures without any sign decay. This enables simulations of the grand-canonical ensemble at large system sizes and low temperatures.…
Investigation of composite Higgs models (CHMs) is of importance in contemporary particle physics. In this article, we present lattice computations of the chimera baryon masses in $Sp(4)$ gauge theory with two and three Dirac flavours of…