he dominant emotion (Sthayi Bhava) of Hāsya Rasa is Hasa, which means mirth.
Explanation
Sthayi Bhava: A static emotion
Hāsya Rasa: The rasa created by the Sthayi Bhava of Hasa
Rasa: A temporary mental state that is the dominant emotion in a dramatic piece
Bhava: An emotion that creates a sense of enjoyment or experience
Bharata Muni's Natyashastra lists eight Sthayibhavas, each corresponding to a rasa.