Diff of two .root files

I diffed two .root files which contain the same numerical values stored in a tree but which were made on different days and I am very confused about why they are different. Does anyone have any idea why the diff would say that the binary files are different? When I do cmp, I find that the first difference occurs for char 48.

Here is the head of what hexdump gives for the first file:

0000000 6f72 746f 0000 e2cd 0000 6400 880d 15e0
0000010 880d a7df 0000 6e00 0000 0100 0000 a800
0000020 0004 0000 0d01 ce88 00d6 1000 00d1 9601
0000030 1601 6e44 117b 97e1 cf17 8a65 be89 00ef
0000040 0000 0000 0000 0000 0000 0000 0000 0000
*
0000060 0000 0000 0000 e400 0400 0000 8000 de44
0000070 079c 6400 0100 0000 6400 0000 0000 5405
0000080 6946 656c 2f42 6164 6174 622f 756c 2f65
0000090 6e61 656c 6976 2f6e 754d 6e6f 6553 656c

and for the second file:

0000000 6f72 746f 0000 e2cd 0000 6400 880d 15e0
0000010 880d a7df 0000 6e00 0000 0100 0000 a800
0000020 0004 0000 0d01 ce88 00d6 1000 00d1 af01
0000030 5f9f 6dc2 11ed 97e1 cf17 8a65 be89 00ef
0000040 0000 0000 0000 0000 0000 0000 0000 0000
*
0000060 0000 0000 0000 e400 0400 0000 8000 dd44
0000070 150d 6400 0100 0000 6400 0000 0000 5405
0000080 6946 656c 2f42 6164 6174 622f 756c 2f65
0000090 6e61 656c 6976 2f6e 754d 6e6f 6553 656c

Okay, maybe this contains the answer: