Related papers: GeV ALP from TeV Vector-like leptons
In hidden-sector models, axion-like particles (ALPs) can couple to heavy neutral leptons (HNLs), leading to rich phenomenologies. We study ALPs produced from $D$- and $B$-meson decays via quark-flavor-violating couplings, and decaying…
I suggest a practical particle model as an extension to the standard model. The model has a TeV scale $U(1)_{B-L}$ symmetry and it contains the fourth generation fermions with the TeV scale masses, in which including a cold dark matter…
Light pseudoscalar resonances that couple to the Standard Model via non-renormalizable operators, such as axions and axion-like particles (ALPs), generate contributions to the renormalization group evolution equations of couplings of…
Several extensions of the Standard Model predict the existence of Axion-Like Particles (ALPs), very light spin-zero bosons with a two-photon coupling. ALPs can give rise to observable effects in very-high-energy astrophysics. Above roughly…
The seesaw and leptogenesis commonly depend on the masses of same particles, and thus are both realized at the same scale. In this work, we demonstrate a new possibility to realize a TeV-scale neutrino seesaw and a natural high-scale…
We review the physics case for very weakly coupled ultralight particles beyond the Standard Model, in particular for axions and axion-like particles (ALPs): (i) the axionic solution of the strong CP problem and its embedding in well…
The exploration of long-lived particles in the MeV-GeV region is a formidable task but it may provide us a unique access to dark sectors. Fixed-target facilities with sufficiently energetic and intense proton beams are an ideal tool for…
We present a search for the direct production of a light pseudoscalar $a$ decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process ${e^+e^-\to\gamma a, a \to\gamma\gamma}$ in the mass range…
Axion-like particles (ALPs), hypothetical pseudoscalar particles that couple to photons, are among the most actively investigated candidates for new physics beyond the Standard Model. Their interaction with gamma rays in the presence of…
Axion-like particles (ALPs) are predicted in many extensions of the Standard Model, and their masses can naturally be well below the electroweak scale. In the presence of couplings to electroweak bosons, these particles could be emitted in…
We investigate the potential of type II supernovae (SNe) to constrain axion-like particles (ALPs) coupled simultaneously to nucleons and electrons. ALPs coupled to nucleons can be efficiently produced in the SN core via nucleon-nucleon…
A predictive framework for supersymmetry at the TeV scale is presented, which incorporates the Ciafaloni-Pomarol mechanism for the dynamical determination of the \mu parameter of the MSSM. It is replaced by (\lambda S), where S is a singlet…
We study the possibility of probing the existence of a light, invisible, axion-like particle (ALP) $a$ in leptonic decays of the $Z$ boson at the proposed high-energy $e^+e^-$ colliders, CEPC and FCC-ee. Both projects plan to run at the $Z$…
We study the effective Lagrangian for the Axion-Like Particle (ALP) arising in a class of composite Higgs models. We discuss the peculiarities of the coupling to the quark sector specific of these models, including flavor violating terms.…
In this paper, we explore the phenomenology of massive Axion-Like Particles (ALPs) coupled to quarks and gluons, dubbed 'QCD ALPs', with an emphasis on the associated low-energy observables. ALPs coupled to gluons and quarks not only induce…
Axion-like particles (ALPs) arise in a variety of theoretical contexts and can, in general, mediate flavor violating interactions and parity non-conservation. We consider lepton flavor violating ALPs with GeV scale or larger masses which…
The problem of the origin of the mu parameter in the Minimal Supersymmetric Standard Model can be solved by introducing singlet supermultiplets with non-renormalizable couplings to the ordinary Higgs supermultiplets. The Peccei-Quinn…
Observational evidences of nonzero neutrino masses and the existence of dark matter request physics beyond standard model. A model with extra scalars and leptonic vector-like fermions is introduced. By imposing a Z_2 symmetry, the neutrino…
A fermion can be chiral or vectorlike with respect to a given symmetry, depending on its coupling to the corresponding gauge boson. Vectorlike fermions have a distinct property that their left-handed and right-handed components behave in…
The theoretical calculation of pseudo-scalar leptonic decay widths into an invisible ALP, $M \to \ell\, \nu_\ell\, a$, is reviewed. Assuming generic flavour-conserving ALP couplings to SM fermions and a generic ALP mass, $m_a$, the latest…