Related papers: A search for the dark photon in the OKA experiment
We propose an experiment to search for invisible decays of orthopositronium (o-Ps) with a 90% confidence sensitivity in the branching ratio as low as $10^{-8}$. Evidence for this decay mode would unambigously signal new physics: either the…
We report a search for a dark photon using $14.9$~fb$^{-1}$ of $e^+e^-$ annihilation data taken at center-of-mass energies from 4.13 to 4.60~GeV with the BESIII detector operated at the BEPCII storage ring. The dark photon is assumed to be…
That massless dark photons could exist and have flavor-changing magnetic-dipole interactions with down-type light quarks is an attractive possibility which may be realized in various new-physics scenarios. It is potentially testable not…
The first search for the $B_s^0\rightarrow K^-\pi^+\gamma$ decay in the range $796<m(K^-\pi^+)<1800\,\text{MeV/}c^2$ is performed using data from proton-proton collisions collected by the LHCb experiment at centre-of-mass energies of 7, 8,…
The results of a new search for positronium decays into invisible final states are reported. Convincing detection of this decay mode would be a strong evid ence for new physics beyond the Standard Model (SM): for example the existence of…
The presently world largest data sample of pi0 --> gamma e+e- decays containing nearly 5E5 events was collected using the WASA detector at COSY. A search for a dark photon U produced in the pi0 --> gamma U --> gamma e+e- decay from the…
Using a data set of 2.93 fb$^{-1}$ taken at a center-of-mass energy $\sqrt{s}$ = 3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a dark photon. We examine the…
A sample of $1.69\times 10^7$ fully reconstructed $\pi^0\to\gamma e^+e^-$ decay candidates collected by the NA48/2 experiment at CERN in 2003--2004 is analysed to search for the dark photon ($A'$) production in the $\pi^0\to\gamma A'$ decay…
A search for the light pseudoscalar sgoldstino production in three-body K- decay K- --> pi-pi0 P has been performed with the ISTRA+ detector exposed to the 25 GeV negative secondary of the U-70 proton synchrotron. No signal is seen. Upper…
The branching ratio in the charged-pion kinetic energy region of 55 to 90 MeV for the direct photon emission in the K- --> pi- pi0 gamma decay has been measured using in-flight decays detected with the ISTRA+ setup operating in the 25 GeV/c…
We present a search for the e+e- decay of a hypothetical dark photon, also names U vector boson, in inclusive dielectron spectra measured by HADES in the p (3.5 GeV) + p, Nb reactions, as well as the Ar (1.756 GeV/u) + KCl reaction. An…
We present a new result on the K^+ --> pi^+ pi^0 gamma decay measurement using stopped kaons. The best fit to the decay spectrum comprised of 10k events gives a branching ratio for the direct photon emission of [3.8+-0.8(stat)+-0.7(syst)]…
We performed a search for a light pseudoscalar particle $X$ in the decay $K_L^0->pi0pi0X$, $X->\gamma\gamma$ with the E391a detector at KEK. Such a particle with a mass of 214.3 MeV/$c^2$ was suggested by the HyperCP experiment. We found no…
The first search for the rare kaon decay $\kppnn$ has been performed by the E391a collaboration at the KEK 12-GeV proton synchrotron. An upper limit of $4.7\times10^{-5}$ at the 90 % confidence level was set for the branching ratio of the…
Neutron dark decays have been suggested as a solution to the discrepancy between bottle and beam experiments, providing a dark matter candidate that can be searched for in halo nuclei. The free neutron in the final state following the decay…
This paper describes a search for dark photons ($\gamma_d$) in proton-proton collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider (LHC). The dark photons are searched for in the decay of Higgs bosons ($H \to \gamma\gamma_d$)…
We report on a direct search for a three-body decay of the orthopositronium into a photon and two penetrating particles, o-Ps -> gamma + X1 + X2. The existence of this decay could explain the discrepancy between the measured and the…
We study the $ZH$ associated production followed by the Higgs $H\to \gamma \bar{\gamma}$ decay into a photon plus an invisible and massless dark photon, at future high-energy $e^+e^-$ facilities. Large $H\to \gamma \bar{\gamma}$ decay rates…
The experimental status of the $K \to \pi \nu \bar{\nu}$ search is presented. The $K \to \pi \nu \bar{\nu}$ decay is sensitive to New Physics because it is theoretically pristine and highly suppressed. The $K_L^0 \to \pi^0 \nu \bar{\nu}$…
Searches for the exclusive decays of the Higgs boson to an $\omega$ meson and a photon or a $K^{*}$ meson and a photon can probe flavour-conserving and flavour-violating Higgs boson couplings to light quarks, respectively. Searches for…