What is {time of discovery or invention} of {W or Z boson} that is {statement is subject of} is {UA2 experiment} ?
When was the W or Z boson discovered?
SELECT ?obj WHERE { wd:Q211922 p:P575 ?s . ?s ps:P575 ?obj . ?s pq:P805 wd:Q1157111 }
select distinct ?obj  where {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> <http://wikidata.dbpedia.org/resource/Q211922> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P575> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> ?obj .
?statement <http://www.wikidata.org/entity/P805> <http://wikidata.dbpedia.org/resource/Q1157111>
} 

What is the date when the W or Z boson was discovered?