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تسجيل مستخدم جديدSearch for a Dark Photon in Electro-Produced $e^{+}e^{-}$ Pairs with the Heavy Photon Search Experiment at JLab
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The Heavy Photon Search experiment took its first data in a 2015 engineering run using a 1.056 GeV, 50 nA electron beam provided by CEBAF at the Thomas Jefferson National Accelerator Facility, searching for an electro-produced dark photon. Using 1.7 days (1170 nb$^{-1}$) of data, a search for a resonance in the $e^{+}e^{-}$ invariant mass distribution between 19 and 81 MeV/c$^2$ showed no evidence of dark photon decays above the large QED background, confirming earlier searches and demonstrating the full functionality of the experiment. Upper limits on the square of the coupling of the dark photon to the Standard Model photon are set at the level of 6$times$10$^{-6}$. In addition, a search for displaced dark photon decays did not rule out any territory but resulted in a reliable analysis procedure that will probe hitherto unexplored parameter space with future, higher luminosity runs.
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The Heavy Photon Search experiment took its first data in a 2015 engineering run at the Thomas Jefferson National Accelerator Facility, searching for a prompt, electro-produced dark photon with a mass between 19 and 81 MeV/$c^2$. A search for a reson
ance in the $e^{+}e^{-}$ invariant mass distribution, using 1.7 days (1170 nb$^{-1}$) of data, showed no evidence of dark photon decays above the large QED background, confirming earlier searches and demonstrating the full functionality of the experiment. Upper limits on the square of the coupling of the dark photon to the Standard Model photon are set at the level of 6$times$10$^{-6}$. Future runs with higher luminosity will explore new territory.
One of the interesting portals linking a dark sector and the standard model (SM) is the kinetic mixing between the SM $U(1)_Y$ field with a new dark photon $A$ from a $U(1)_{A}$ gauge interaction. Stringent limits have been obtained for the kinetic m
ixing parameter $epsilon$ through various processes. In this work, we study the possibility of searching for a dark photon interaction at a circular $e^+e^-$ collider through the process $e^+ e^-to gamma A^{prime *} to gamma mu^+mu^-$. We find that the constraint on $epsilon^2$ for dark photon mass in the few tens of GeV range, assuming that the $mu^+mu^-$ invariant mass can be measured to an accuracy of $0.5%m_{A}$, can be better than $3times 10^{-6}$ for the proposed CEPC with a ten-year running at 3$sigma$ (statistic) level, and better than $2times 10^{-6}$ for FCC-ee with even just one-year running at $sqrt{s} = 240$ GeV, better than the LHC and other facilities can do in a similar dark photon mass range. For FCC-ee, running at $sqrt{s}=160$ GeV, the constraint can be even better.
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 pp-->pppi^0 re
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We are building an experiment to search for dark matter in the form of dark photons in the nano- to milli-eV mass range. This experiment is the electromagnetic dual of magnetic detector dark radio experiments. It is also a frequency-time dual experim
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