Related papers: Light gauge boson in rare $K$ decay

We study rare three- and four-body kaon decays as a probe of light vector and axial-vector bosons coupled to non-conserved currents. We find that searches for $K_L \to \pi^0 \pi^0 (X\to e^+e^-)$ decays constrain the couplings of light $X$…

We evaluate constraints from flavor changing rare meson decays to a light vector boson $X$, followed by the decay of the on-shell $X$ into the SM fermions. The flavor changing meson decay emitting the light $X$ is induced by loop processes…

In this paper, we explore the constraints that the LHC can place on a massive gauge boson $X$ that predominantly couples to the third generation of fermions. Such a gauge boson arises in scenarios where the $B-L$ of the third generation is…

The rare Higgs boson decay $H\to Z\gamma$ is forbidden at tree-level. In the Standard Model, it is loop-mediated through a $W$ boson or a heavy quark. We analytically compute the QCD correction to the heavy quark loop, confirming earlier…

Single W and single gamma productions which are sensitive to the trilinear gauge coupling WWgamma have been studied at LEP. It isshown that single W production has particular sensitivity to the "anomalous" magnetic moment Kgamma of the W…

We searched for the $\mu^+\mu^-$ decay of a light vector gauge boson, also known as dark photon, in the $e^+ e^- \to \mu^+ \mu^- \gamma_{\rm ISR}$ process by means of the Initial State Radiation (ISR) method. We used 1.93~fb$^{-1}$ of data…

We present a detailed analysis of the rare exclusive Higgs-boson decays into a single vector meson and a photon and investigate the possibility of using these processes to probe the light-quark Yukawa couplings. We work with an effective…

The phenomenological model of an extra U(1) neutral gauge Z' boson coupled to heavy quarks is presented. In particular, we discuss the probability for a light $Z_{2}$ mass eigenstate decay into a bound state composed of heavy quarks via…

We recall how a new light gauge boson emerged in Supersymmetric extensions of the Standard Model with an extra singlet superfield, and how it could behave very much as a light pseudoscalar, with the corresponding symmetry broken at a scale…

A new exclusion limit for the electromagnetic production of a light U(1) gauge boson {\gamma}' decaying to e^+e^- was determined by the A1 Collaboration at the Mainz Microtron. Such light gauge bosons appear in several extensions of the…

We reconsider the lambda-SUSY model, in which the mass of the Higgs boson is raised already at tree level up to about 200 GeV via an additional interaction in the superpotential between the Higgs bosons and a Singlet, focusing on a scale…

A search was made for a new light gauge boson $X$ which might be produced in $\pi^{0}\to\gamma + X$ decay from neutral pions generated by 450-GeV protons in the CERN SPS neutrino target. The X's would penetrate the downstream shielding and…

The Grossman-Nir bound concept is robust, but the common perception of $K_L \to \pi^0\nu\bar\nu < 1.4 \times 10^{-9}$ may be circumvented. Because of the blinding $K\pi2$(3) decay, $K^+$ decay experiments such as E787/E949 and the currently…

We present a detailed calculation of the rare decay Z --> neutrino antineutrino photon photon via the quartic neutral gauge boson coupling Z-Z-photon-photon in the framework of the effective Lagrangian approach. The current experimental…

The processes of pair production of S- and P- wave charmonium, as well as the production of the tetraquark (cc \bar{c} \bar{c}) in the Higgs boson decays are investigated within the framework of relativistic quark model. Relativistic decay…

We report new experimental limits on the \pi^0 -> \gamma X decay of the neutral pion into a photon and a light boson X followed by the decay X -> e+e-. If this process exist, one would expect a flux of high energy X's produced from \pi^0's…

The realization that first- and second-generation Yukawa couplings can be probed by decays of the Higgs boson to a meson in association with a photon has renewed interest in such rare exclusive decays. We present here a detailed study of…

We study single production of exotic vectorlike $Y$ quark with electric charge $|Q_{Y}|=4/3$ and its subsequent decay at the High Luminosity LHC (HL-LHC). Most of the vector like quark (VLQ) decays have the electroweak $W$ bosons in the…

We explore quark interactions mediated by new gauge bosons of masses in the 0.3 - 50 GeV range. A tight upper limit on the gauge coupling of light Z' bosons is imposed by the anomaly cancellation conditions in conjunction with collider…

We present a new limit on the production of a light dark-force mediator with the KLOE detector at DAPHNE. This boson, called U, has been searched for in the decay phi --> eta U, U --> e+ e-, analyzing the decay eta --> pi0 pi0 pi0 in a data…