().

Antichastica po otnosheniyu k neitrino. Eksperimental'nye dannye pokazyvayut, chto s elektronom, myuonom i taonom (tau-leptonom) associiruyutsya tri razlichnyh tipa neitrino i sootvetstvenno tri tipa antineitrino: elektronnoe (), myuonnoe () i taonnoe (). Prinyato opredelyat' antineitrino kak legkii neitral'nyi lepton, obrazuyushiisya v processah slabogo vzaimodeistviya vmeste s sootvetstvuyushim otricatel'no zaryazhennym leptonom. Naprimer, opredelyaetsya kak chastica, rozhdayushayasya vmeste s v raspade . Takoe opredelenie antineitrino predpolagaet, chto kazhdomu tipu leptonov sootvetstvuet svoe sohranyayusheesya leptonnoe chislo (elektronnoe, myuonnoe, tau-leptonnoe). Spin antineitrino raven 1/2. Vo vseh nablyudavshihsya processah rozhdeniya i vzaimodeistviya antineitrino obladaet opredelennoi - pravoi - spiral'nost'yu. Vopros o sushestvovanii antineitrino s levoi spiral'nost'yu ostaetsya otkrytym. Etot vopros osobenno vazhen v svyazi s vozmozhnym nalichiem u neitrino massy. Esli massa neitrino - dirakovskaya (t. e. neitrino opisyvaetsya chetyrehkomponentnoi volnovoi funkciei, udovletvoryayushei uravneniyu Diraka), to dolzhny sushestvovat' i sostoyaniya antineitrino s levoi spiral'nost'yu. Esli massa neitrino - maioranovskaya (t. e. neitrino - massivnaya maioranovskaya chastica), to neitrino okazyvaetsya istinno neitral'nym fermionom i nablyudaemye sostoyaniya neitrino i antineitrino yavlyayutsya raznymi spiral'nymi sostoyaniyami odnoi istinno neitral'noi chasticy.