Isit possible to prevent an OS (dual boot) to access/mount any other partition?
On x86/x64, the operating system has full access to the system and underlying hardware. Unless you disable these drives in BIOS, the OS will be able to access them (and in fact, with UEFI the OS theoretically can enable them again).
Drive encryption is a possible solution, as is running the Ubuntu in a virtual machine. If you split the operating systems across different physical drives, you could disconnect the cables.
Besides that; I highly doubt that any security software would be searching for unmounted partitions, mount them and then start scanning them.