Does sin befall one who unintentionally tears a part of the Mushaf?

If your daughter's action resulted from your own shortcoming or negligence, then the sin is solely upon you. You must repent to Allah, increase your supplications for forgiveness, resolve never to repeat such an act, and engage more in good deeds and charity.

However, if there was no shortcoming on your part, then, Allah willing, there is no sin upon you. Nevertheless, you must keep thebook of Allah out of the reach of children. There is no sin on the daughter, as the pen is lifted from her.