Check this book out 

A Zeptospace Odyssey 

There is a table in this book similar to the periodic table of elements we all know from chemistry. It is a periodic table of elementary particles . There is a gap-like space in that table much like the gap which was in the periodic table of elements before many new elements were discovered.
You could easily expect the gap to be the place of some undiscovered elementary particles which are force carriers of another yet undiscovered force ; i.e. The Force Of Life !

Read the book and check the table for yourself .
You won't regret.