Proton

http://www.mpq.mpg.de/cms/mpq/en/news/press/10_07_08.html
http://www.nature.com/news/2010/100707/full/news.2010.337.html
http://www.membrana.ru/articles/inventions/2010/07/09/203400.html

proton rms charge radius 
 
 Value  0.8768 x 10-15 m  
 Standard uncertainty  0.0069 x 10-15 m   
 Relative standard uncertainty   7.8 x 10-3  
 Concise form  0.8768(69) x 10-15 m     

http://physics.nist.gov/cgi-bin/cuu/Value?rp#mid