According to Official Guinness Records,
The largest broom (t-shaped) measured 11.68 m long (38 ft 3.84 in) and 6.04 m (19 ft 9.8 in) wide and was manufactured by Liane Scharnefski-Karle and Armin Karle and their team (all Germany) in Bad Schussenried-Kürnbach, Germany, on 29 April 2007.
For exact measurements of all other dimensions please check the attachments in the toolkit.
For a complete list of 2007 records, please visit 2007 Guinness Records in Germany.