Heidelberg 2015 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
HK: Fachverband Physik der Hadronen und Kerne
HK 53: Heavy Ion Collisions and QCD Phases 6
HK 53.3: Talk
Thursday, March 26, 2015, 15:15–15:30, T/HS1
Searching for a Dark Photon with HADES — •Carina Ungethuem for the HADES collaboration — TU Darmstadt
Approximately 25 % of our universe consists of dark matter (DM). It is possible that the DM
(DM) interacts with the visible matter via a U(1) gauge boson, the so called U-boson (A’, γ’ or dark photon).
The standard model (SM) is thereby supplemented with an additional sector characterized by the U(1)’ symmetry, which gives the
counterpart to the SM U(1) symmetry. The kinetic mixing of the U(1) and U(1)’ symmetry groups gives a natural connection between the
SM and DM. The dark photon is constrained to be in the MeV to GeV range and should have a small width of Γu ≪ 1 MeV/c2. Such models are
also proposed to explain some recent puzzling astrophysical observations, as well as to solve the sofar unexplained deviation between the
measured and calculated values of the muon anomaly. We present a search for the e+e− decay of such a hypothetical dark photon in inclusive dielectron
spectra measured by HADES in the Au (1.23 GeV) + Au reaction. An upper limit on the kinetic mixing parameter at 90% CL
has been obtained for a mass range lower than 0.6 GeV/c2 and is compared with the present world data set. We are aiming at a lowering of the
upper limit for masses below 0.1 GeV/c2 in order to exclude a further part of the parameter region favored by the muon g-2 anomaly.
Supported by: VH-NG-823, Helmholtz Alliance HA216/EMMI and GSI