Question: what is the nuclear symbol for a beta particle
[{'answer': 'β', 'provenance': [{'wikipedia_id': '37872', 'title': 'Beta particle', 'start_paragraph_id': 1, 'start_character': 64, 'end_paragraph_id': 1, 'end_character': 65, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '37872', 'title': 'Beta particle', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 312, 'bleu_score': 0.9632870032952191, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4712389435900822477}, 'section': 'Section::::Abstract.'}]}]