Hadron Fiducial Cuts for the CLAS E5 Data

We have developed selection cuts for positively-charged hadrons from the $D(\vec e,e^\prime p)n$ reaction in the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. CLAS measures the scattering of electron and photon beams on nuclear targets and is a large, complex, particle detector. For accurate measurements we select data from regions of CLAS where its response is well understood and not changing quickly. We use fiducial cuts to define the regions of CLAS where the azimuthal dependence of positive hadrons is constant. First, a trapezoidal function is fitted to this azimuthal dependence in a particular scattering angle and momentum bin of a proton or positive pion. Next, the limits of the trapezoid's plateau are fitted as a function of the hadron scattering angle for each momentum bin. Last, the parameters of this second generation fit are, in turn, fitted as functions of hadron momentum to give us well-behaved functions defining the active region of CLAS. We will discuss the details of this method and apply it to the the electrodisintegration of the deuteron in the $D(\vec e,e^\prime p)n$ reaction. The data were collected at two beam energies, 2.6 GeV and 4.2 GeV. Different magnetic field polarities were used for the 2.6-GeV data to cover a broader $\rm Q^2$ range.