3 years ago

The triplet photoproduction on a free electron as a possible way to search for a dark photon.

N.P. Merenkov, M.I. Konchatnij, G.I. Gakh

The process of the triplet production on a free electron, $\gamma e^-\to e^+e^-e^-$, has been investigated as a reaction where a dark photon, $A'$, is produced as a virtual state with subsequent decay into a $e^+e^-$-pair. This effect arises due to the so-called kinetic mixing and is characterized by the small parameter $\epsilon$ describing the coupling strength relative to the electric charge e.

The search of $A'$ in this process has advantage because the background to the $A'$ signal is pure QED. This QED background is described by eight Feynman diagrams taking into account the identity of final electrons. As concern $A'$, we leave its contribution in Compton-like diagrams only since, in this case, the virtual dark photon is time-like and its propagator has the Breit-Wigner form. So, near the resonance $A'$ can manifest itself. The contribution of $A'$ in Borsellino diagrams is negligible since, in this case, the virtual dark photon is space-like, the $A'$ propagator does not peak and effect is proportional at least to $\epsilon^2$. We calculate the distributions over the invariant masses of the both produced $e^+e^-$ pairs and search for the kinematical region where the Compton-like diagrams contribution is not suppressed as compared with the Borsellino one. We estimate what value of the parameter $\epsilon$, as a function of the dark photon mass, can be obtained at given number of the measured events.

Publisher URL: http://arxiv.org/abs/1711.01770

DOI: arXiv:1711.01770v1

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.