相关论文: Probing Invisible Vector Meson Decays with NA64 an…
The dark photon ($A'$) production through the mixing with the bremsstrahlung photon from the electron scattering off nuclei can be accompanied by the dominant invisible $A'$ decay into dark-sector particles. In this work we discuss the…
We investigate the prospects for detecting light leptophilic dark sectors with a missing-momentum experiment at NA64 running in muon mode. In particular, we consider models in which dark matter connects to the visible sector through a…
We present an initial design study for LDMX, the Light Dark Matter Experiment, a small-scale accelerator experiment having broad sensitivity to both direct dark matter and mediator particle production in the sub-GeV mass region. LDMX…
We discuss the mechanism to produce electron-specific dark matter mediators of spin-0 and spin-2 in the electron fixed target experiments such as NA64 and LDMX. The secondary positrons induced by the electromagnetic shower can produce the…
The Light Dark Matter eXperiment (LDMX) is a proposed fixed-target missing momentum search for sub-GeV thermal relic dark matter. LDMX aims to probe thermal dark matter targets with 1016 electrons on target. Such an approach requires a…
We describe an approach to detect dark matter and other invisible particles with mass below a GeV, exploiting missing energy-momentum measurements and other kinematic features of fixed-target production. In the case of an invisibly decaying…
Millicharged particles emerge as compelling candidates in numerous theoretically well-motivated extensions of the Standard Model. These hypothetical particles, characterized by an electric charge that is a small fraction of the elementary…
We report on a search for a new $Z'$ ($L_\mu-L_\tau$) vector boson performed at the NA64 experiment employing a high energy muon beam and a missing energy-momentum technique. Muons from the M2 beamline at the CERN Super Proton Synchrotron…
We report the first results on a direct search for a new 16.7 MeV boson (X) which could explain the anomalous excess of e+e- pairs observed in the excited Be-8 nucleus decays. Due to its coupling to electrons, the X could be produced in the…
The NA64 experiment consists of two detectors which are planned to be located at the electron (NA64e) and muon (NA64$\mu$) beams of the CERN SPS and start operation after the LHC long-stop 2 in 2021. Its main goals include searches for dark…
Among laboratory probes of dark matter, fixed-target neutrino experiments are particularly well-suited to search for light weakly-coupled dark sectors. In this paper, we show that the DAEdALUS source setup---an 800 MeV proton beam impinging…
Some extensions of the Standard Model consider inelastic dark matter (iDM) as an attractive candidate for sub-GeV DM of thermal origin that could be detected at modern accelerators. In the present paper, we calculate the production rate of…
We explore hypothetical vector particles, dark photons $\gamma'$, which mix with the Standard Model photons and thus mediate interactions with charged particles into the hidden sector. We study the elastic proton bremsstrahlung of dark…
We present the results of a missing-energy search for Light Dark Matter which has a new interaction with ordinary matter transmitted by a vector boson, called dark photon $A^\prime$. For the first time, this search is performed with a…
The Light Dark Matter eXperiment (LDMX) is proposed to employ a thin tungsten target and a multi-GeV electron beam to carry out a missing momentum search for the production of dark matter candidate particles. We study the sensitivity for a…
High luminosity colliders and fixed target facilities using proton beams are sensitive to new weakly coupled degrees of freedom across a broad mass range. Among the various production modes, bremsstrahlung is particularly important for dark…
Thermal dark matter models with particle $\chi$ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and…
We explore the sensitivity of collider experiments to a broad class of GeV-scale dark vector models of new physics via production in proton and neutron bremsstrahlung and initial state radiation. This is achieved using a new physically…
A light $Z'$ vector boson coupled to the second and third lepton generations through $L_{\mu}-L_{\tau}$ current with mass below 200 MeV provides a very viable explanation in terms of new physics to the recently confirmed $(g-2)_\mu$…
In rich dark sector models, dark photons heavier than tens of MeV can behave as semi-visible particles: their decays contain both visible and invisible final states. We present models containing multiple dark fermions which allow for such…