The Heavy Photon Search experiment at Jefferson Laboratory

Marzio De Napoli,G Giardina,G Venanzoni,M Battaglieri,G Mandaglio,S Eidelman

doi:10.1051/epjconf/20159601010

Abstract

Many beyond Standard Model theories predict a new massive gauge boson, aka “dark” or “heavy photon”, directly coupling to hidden sector particles with dark charge. The heavy photon is expected to mix with the Standard Model photon through kinetic mixing and therefore couple weakly to normal charge. The Heavy Photon Search (HPS) experiment will search for the heavy photon at the Thomas Jefferson National Accelerator Facility (JLab), in the mass range 20-1000 MeV/c2 and coupling to electric charge ϵ 2 = α′/α in the range 10−5 to 10−10 . HPS will look for the e+ e− decay channel of heavy photons radiated by electron Bremsstrahlung, employing both invariant mass search and detached vertexing techniques. The experiment employs a compact forward spectrometer comprising silicon microstrip detectors for vertexing and tracking and an electromagnetic calorimeter for particle identification and triggering.

Highlights

The existence of an additional U(1) gauge symmetry in nature is predicted by several beyond the Standard Model theories [1, 2]
The heavy photon is expected to mix with the Standard Model photon through kinetic mixing and couple weakly to normal charge
The Heavy Photon Search (HPS) experiment will search for the heavy photon at the Thomas Jefferson National Accelerator Facility (JLab), in the mass range 20-1000 MeV/c2 and coupling to electric charge 2 = α /α in the range 10−5 to 10−10

Summary

Introduction

The existence of an additional U(1) gauge symmetry in nature is predicted by several beyond the Standard Model theories [1, 2]. The associated gauge boson A , called "dark" or "heavy photon", can mix kinematically with the photon through quantum loops of heavy particles that carry both the standard model hypercharge and the dark force equivalent [3, 4]. This kinetic mixing results in an effective interaction magnetic current JEμM, eAμ JEμ M of the A suppressed relative to to the the electroelectron charge e by a factor. The lack of excess in the antiproton-to-proton ratio suggests a mass of A lower than

The HPS Experiment

Experimental setup

Findings

HPS reach