Measurement of the Bjorken Sum at very low $Q^2$

A. Deur, 2 J. P. Chen, S. E. Kuhn, C. Peng, M. Ripani, V. Sulkosky, 1, 2 K. Adhikari, 1, 7 M. Battaglieri, 5 V. D. Burkert, G. D. Cates, R. De Vita, G. E. Dodge, L. El Fassi, 7 F. Garibaldi, 9 H. Kang, M. Osipenko, J. T. Singh, K. Slifer, 11 J. Zhang, and X. Zheng Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA University of Virginia, Charlottesville, Virginia 22904, USA Old Dominion University, Norfolk, Virginia 23529, USA Duke University, Durham, NC 27708, USA INFN, Sezione di Genova, 16146 Genova, Italy College of William and Mary, Williamsburg, VA 23187, USA Mississippi State University, Mississippi State, Mississippi, MS 39762, USA INFN, Sezione di Roma, I-00185 Rome, Italy Istituto Superiore di Sanità, I-00161 Rome, Italy Seoul National University, Seoul, Korea University of New Hampshire, Durham, NH 03824, USA