Yes. It is possible
The spermatozoa deposited by a man into the female genital tract (during sexual intercourse and subsequent ejaculation) can last for very few days before the actual fertilization.
If a woman has sex with a man, and within few hours later on have sex with another man; if two egg cells(ova) were released from her ovaries via ovulation, then there’s a tendency that the fertilization of the two ova by the two different spermatozoa(from both men she had sex with) may occur around the same time.
Thus, producing dizygotic/fraternal twins of two different fathers(since the sperm came from two different men).
This phenomenon is called “heteropaternal superfecundation” in clinical Embryology