Which of these particle physics processes occurs at a higher rate? As in the title! The processes are:
$$cud \to sud + u\bar d$$
$$cud \to udd + \bar su$$
Obviously in the first one, the $c$ quark decays into an $s$ quark, and in the second, the $c$ quark decays into a d quark, so I'm guessing flavour mixing comes into the answer. My thinking would be that it's more likely to "keep" its flavour, and so the first option happens more often, but I'm not sure of the reasoning behind that.
 A: The s quark is characterized by strangeness = -1 and the anti_s quark +1

The terms strange and strangeness predate the discovery of the quark, and were adopted after its discovery in order to preserve the continuity of the phrase; strangeness of anti-particles being referred to as +1, and particles as −1 as per the original definition. For all the quark flavour quantum numbers (strangeness, charm, topness and bottomness) the convention is that the flavour charge and the electric charge of a quark have the same sign.

Here is a table of the possible quark decays:

The equivalent antiquark table has a bar over the decayed quark of the table above and appropriate charge changes for the W and further reactions.
When antiparticles decay, they decay to antiparticles, baryon  and antibaryon number is a conserved number and an antiquark has to have a -1/3  baryon number.
Here are the quantum numbers of quarks


c quark decays into a d quark,

This is not an allowed decay, 
A charmed quark can only decay to an s quark, not an anti-s, or any other quark than s. The second line is also  violating flavor number conservation: anti-s flavor suddenly appears.
