1 2   fm ) ▁and ▁perhaps ▁explain ▁the ▁decay ▁of ▁these ▁ 8 Be ▁excited ▁states . ▁A ▁ 2 0 1 8 ▁r er un ▁of ▁this ▁experiment ▁found ▁the ▁same ▁anom alous ▁particle ▁scatter ing , ▁and ▁set ▁a ▁nar ro wer ▁mass ▁range ▁of ▁the ▁proposed ▁fifth ▁bos on , ▁ ▁Me V / c 2 . ▁While ▁further ▁experiments ▁are ▁needed ▁to ▁cor ro bor ate ▁these ▁observations , ▁the ▁influence ▁of ▁a ▁fifth ▁bos on ▁has ▁been ▁proposed ▁as ▁" the ▁most ▁straightforward ▁possibility ". ▁ ▁Ro le ▁in ▁stell ar ▁nucle os yn thesis ▁ ▁In ▁stell ar ▁nucle os yn thesis , ▁two ▁hel ium - 4 ▁nuc lei ▁may ▁col lide ▁and ▁f use ▁into ▁a ▁single ▁b ery l li um - 8 ▁nucle us . ▁B ery l li um - 8 ▁has ▁an ▁extremely ▁short ▁half - life ▁( 8 . 1 9   seconds ), ▁and ▁dec ays ▁back ▁into ▁two ▁hel ium - 4 ▁nuc lei . ▁This , ▁along ▁with ▁the ▁un bound ▁nature ▁of ▁ 5 He ▁and ▁ 5 Li , ▁creates ▁a ▁bott l ene ck ▁in ▁Big ▁Bang ▁nucle os yn thesis ▁and ▁stell ar ▁nucle os yn thesis , ▁for ▁it ▁necess it ates ▁a ▁very ▁fast ▁reaction ▁rate . ▁This ▁imp edes ▁formation ▁of ▁heav ier ▁elements ▁in ▁the ▁former , ▁and ▁limits ▁the ▁yield ▁in ▁the ▁latter ▁process . ▁If ▁the ▁b ery l li um - 8 ▁coll ides ▁with