I could not find any scientific papers that have done research into this phenomenon but the general reason given for wilted flowers to being resuscitated is given as the hot water being absorbed faster and I quote
> Florists use warm water only for resuscitating wilted flowers, because warm water is absorbed quickly. For restoring wilted stems, hot water (110 degrees Fahrenheit) is recommended. For woody or badly wilted stems, very hot water (180 to 200 degrees) is better. Florists then move them into a refrigerator (reference).
The reason for absorbtion faster is given as
luke warm water in a vase arrangement because warm water is “thinner” (has fewer air bubbles) and moves up the stem faster than cold water (reference) and Warm water molecules move faster than cold water molecules and so can be absorbed by flowers with greater ease (reference).