arXiv subjects

Yohei Nakashima

Publications and source records attributed to Yohei Nakashima.

2 recordsLinked to original sources

arXiv2026

Dark photon and U(1)$_{B-L}$ gauge boson from dark Higgs boson decays at FASER and SHiP

We study the sensitivity to dark photons and U(1)$_{B-L}$ gauge bosons produced via dark Higgs boson decays at the FASER and SHiP experiments. In addition to pair production of these vector bosons from both on-shell and off-shell dark Higgs boson decays, a new production process of single vector boson associated with the standard model particles is taken into account. Constraints on the parameter space of dark photon are derived with including the latest results from the FASER experiment. The expected sensitivity regions to the dark photon and U(1)$_{B-L}$ gauge boson of the future FASER2 and SHiP experiments are presented. The sensitivity to the U(1)$_{B-L}$ model with freeze-in sterile neutrino dark matter is also discussed.

hep-ph↗

arXiv2024

Dark photon pair production via off-shell dark Higgs at FASER

We consider a dark photon model in which the dark U(1) gauge symmetry is spontaneously broken by a vacuum expectation value of a new scalar boson. We focus on the ForwArd Search ExpeRiment (FASER) and calculate its sensitivity to the dark photon produced from the off-shell decay of the new scalar boson. It is found that the off-shell production extends the sensitivity region beyond the kinematical threshold of the on-shell decay of the scalar boson, and that the sensitivity region can be spanned to unexplored region. We also show the parameter space in which perturbative calculation is valid for the unitarity of an S matrix.

hep-ph↗