Related papers: Singlet Mesons in Dark $Sp(4)$ Theories
We investigate a perturbative extension of the Standard Model featuring elementary pseudo-Goldstone Higgs and dark matter particles. These are two of the five Goldstone bosons parametrising the SU(4)/Sp(4) coset space. They acquire masses,…
The appearance of a light composite $0^+$ scalar resonance in nearly conformal gauge-fermion theories motivates further study of the low energy structure of these theories. To this end, we present a nonperturbative lattice calculation of…
We present the spectrum of baryons in a new SU(4) gauge theory with fundamental fermion constituents. The spectrum of these bosonic baryons is of significant interest for composite dark matter theories. Here, we compare the spectrum and…
The massive Schwinger model with two flavors is studied in the strong coupling region by using light-front Tamm-Dancoff approximation. The mass spectrum of the lightest particles is obtained numerically. We find that the mass of the…
We consider models of accidental dark matter, namely models in which the dark matter is a composite state that is stable thanks to an accidental symmetry of the theory. The fundamental constituents are vectorlike fermions, taken to be…
We report the results of lattice numerical studies of the Sp(4) gauge theory coupled to fermions (hyperquarks) transforming in the fundamental and two-index antisymmetric representations of the gauge group. This strongly-coupled theory is…
The Higgs spectrum of the minimal composite Higgs model, based on the SO(5)/SO(4) coset, consists of a unique Higgs doublet whose phenomenology does not differ greatly from the Standard Model (SM). Nevertheless, extensions beyond this…
We report on the first lattice determination of the pseudoscalar meson $\eta_c$ light-cone distribution amplitude, using a set of three CLS $N_f=2$ ensembles at a pion mass $m_{\pi} \sim 270~\text{MeV}$ and lattice spacings $a \sim…
We present a non-perturbative lattice study of SU(4) gauge theory with two flavors of fermions in the fundamental representation and two in the two-index antisymmetric representation: a theory closely related to a minimal…
In view of the recent diboson resonant excesses reported by both ATLAS and CMS Collaborations, we suggest that a new weak singlet pseudo-scalar particle, $\eta_W$, may decay into two weak bosons while being produced in gluon fusion at the…
We perform calculations for the $\eta_c \to \eta \pi^+ \pi^-$ decay using elements of SU(3) symmetry to see the weight of different trios of pseudoscalars produced in this decay, prior to the final state interaction of the mesons. After…
We investigate the connection between simplified dark matter models featuring a $t$-channel scalar mediator and the Standard Model Effective Field Theory (SMEFT). We focus on scenarios with fermionic dark matter interacting with leptons,…
We examine simple extension of the standard model with a pair of fermions, one singlet and a doublet, in a common thread linking the dark matter problem with the smallness of neutrino masses associated with several exciting features. In the…
The new observation of CDMS II favors low mass WIMPs. Taking the CDMS II new results as inputs, we consider a SM singlet: the darkon as the dark matter candidate, which can be either scalar, fermion or vector. It is found that the simplest…
We propose an extended $3+1$ Higgs doublet model where the Standard Model (SM) gauge structure is enhanced by the discrete symmetry $Q_6 \times Z_2 \times Z_4$, and the fermion content is extended with right-handed Majorana neutrinos. The…
In any gauge extension of the standard model (SM) of quarks and leptons, there is a minimal set of fermion and scalar multiplets which encompasses all the particles and interactions of the SM. Included within this set, there may be a…
We investigate an one loop radiative neutrino mass model, where the loop particles, notably a singlet fermion ($\chi$), a doublet fermion ($\Psi$) and three generations of singlet scalars ($\phi_i, i=\{1,2,3\}$) are assumed to be odd under…
The minimal dark matter model is given a supersymmetric extension. A super SU(2)L quintuplet is introduced with its fermionic neutral component still being the dark matter, the dark matter particle mass is about 19.7 GeV. Mass splitting…
As discussed recently by Hooper and Tait, the singlino-like dark matter in the Minimal Supersymmetric Standard Model (MSSM) extended by a singlet Higgs superfield can give a perfect explanation for both the relic density and the Pamela…
The Singlet-Doublet model of dark matter is a minimal extension of the Standard Model with dark matter that is a mixture of a singlet and a non-chiral pair of electroweak doublet fermions. The stability of dark matter is ensured by the…