Precision Determination of the Neutral Weak Form Factor of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Ca</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>48</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>
D. Adhikari, H. Al-Bataineh, D. Androić, K. Aniol, David Armstrong, T. Averett, C. Ayerbe Gayoso, S. Barcus, Vincenzo Bellini, R. Beminiwattha, Jay Benesch, H. Bhatt, D. Bhatta Pathak, D. Bhetuwal, B. Blaikie, J. Boyd, Q. Campagna, A. Camsonne, G. D. Cates, Y. Chen, C. Clarke, J. C. Cornejo, S. Covrig Dusa, M. M. Dalton, P. Datta, A. Deshpande, D. Dutta, Charles Feldman, E. Fuchey, C. Gal, D. Gaskell, T. Gautam, Michael Gericke, C. Ghosh, I. Halilovic, O. Hansen, O. Hassan, F. Hauenstein, W. Henry, C. J. Horowitz, Christopher Jantzi, Siyu Jian, S. Johnston, D. Jones, S. Kakkar, Sumudu Katugampola, C. E. Keppel, P. M. King, David E. King, K.S. Kumar, T. Kutz, N. Lashley-Colthirst, Graham Leverick, H. Liu, N. Liyanage, J. Mammei, R. Mammei, M. McCaughan, D. McNulty, D. Meekins, Carrington Metts, R. Michaels, M. Mihovilovič, M. M. Mondal, J. Napolitano, A. Narayan, D. Nikolaev, V. Owen, C. Palatchi, Jie Pan, B. Pandey, S. Park, K. Paschke, M. Petrusky, M. L. Pitt, S. Premathilake, B. Quinn, Robert Radloff, S. Rahman, M. N. H. Rashad, A. Rathnayake, Brendan T. Reed, P. E. Reimer, R. K. Richards, S. Riordan, Y. Roblin, S. Seeds, A. Shahinyan, P. A. Souder, M. Thiel, Y. Tian, G. M. Urciuoli, E. W. Wertz, B. Wojtsekhowski, B. Yale, Ye Tao, A. S. Yoon, Weizhi Xiong, A. Zec, W. Zhang
Abstract
We report a precise measurement of the parity-violating (PV) asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{48}Ca. We measure A_{PV}=2668±106(stat)±40(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(q=0.8733 fm^{-1})=0.1304±0.0052(stat)±0.0020(syst) and the charge minus the weak form factor F_{ch}-F_{W}=0.0277±0.0055. The resulting neutron skin thickness R_{n}-R_{p}=0.121±0.026(exp)±0.024(model) fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.