In contrast, fermions are usually associated with matter (although in quantum physics the distinction between the two concepts is not clear cut).Bosons may be either elementary, like photons, or composite, like mesons.All observed bosons have integer spin, as opposed to fermions, which have half-integer spin.. 
ìpéjọ́nípa ṣẹlẹ̀ gidigidi ní apágúúsù orílẹ̀-èdè Amẹ́ríkà láti 1890 dé àwọn ọdún 1920, pẹ̀lú 1892 bíi ọdún tó ṣẹlẹ̀ jùlọ.. 