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Positrons beam dump experiments have unique features to search for very narrow resonances coupled superweakly to $e^+ e^-$ pairs. Due to the continue loss of energy from soft photon bremsstrahlung, in the first few radiation lengths of the dump a positron beam can continuously scan for resonant production of new resonances via $e^+$ annihilation off an atomic $e^-$ in the target. In the case of a dark photon $A$ kinetically mixed with the photon, this production mode is of first order in the electromagnetic coupling $alpha$, and thus parametrically enhanced with respect to the $O(alpha^2)$ $e^+e^- to gamma A$ production mode and to the $O(alpha^3)$ $A$ bremsstrahlung in $e^--$nucleon scattering so far considered. If the lifetime is sufficiently long to allow the $A$ to exit the dump, $A to e^+e^-$ decays could be easily detected and distinguished from backgrounds. We explore the foreseeable sensitivity of the Frascati PADME experiment in searching with this technique for the $17,$MeV dark photon invoked to explain the $^8$Be anomaly in nuclear transitions.
High energy positron annihilation is a viable mechanism to produce dark photons ($A^prime$). This reaction plays a significant role in beam-dump experiments using experiments using multi-GeV electron-beams on thick targets by enhancing the sensitivit
A wealth of new physics models which are motivated by questions such as the nature of dark matter, the origin of the neutrino masses and the baryon asymmetry in the universe, predict the existence of hidden sectors featuring new particles. Among the
We consider the light $Z$ explanation of the muon $g-2$ anomaly. Even if such a $Z$ has no tree-level coupling to electrons, in general one will be induced at loop-level. We show that future beam dump experiments are powerful enough to place stringen
A novel mechanism to produce and detect Light Dark Matter in experiments making use of GeV electrons (and positrons) impinging on a thick target (beam-dump) is proposed. The positron-rich environment produced by the electromagnetic shower allows to p
The review of using of compton backscattering method for determination of the beam energy in collider experiments is given.