How can dark matter explain the need for modifications to the CDM model?

[mesogen]

Because of friction, a black hole is more of en effective target for ordinary matter than it is for dark matter. See

https://www.physicsforums.com/showthread.php?p=2000505#post2000505.

But if there is 5x as much dark matter, it should maybe compete to some degree with regular matter. I wonder if anyone has estimated the ratio of matter to dark matter that would tend to find its way into a black hole.

 

[mesogen]

From the other thread that you linked to (where I also see that, yes, someone has estimated the ratio):

This is why, I think, in the link you gave, Peirani and Pacheko say that "dark matter particles constitute a collisionless fluid".

So, if the particles of dark matter cannot collide at all, then can they superimpose will nilly? As in, dark matter particles can be in the same place at once, or a trillion of them can also occupy the same space all at once? There is absolutely no "collision" whatsoever? Wow.

 

[Dmitry67]

As in, dark matter particles can be in the same place at once, or a trillion of them can also occupy the same space all at once? There is absolutely no "collision" whatsoever? Wow.

1 Pauli exclusion principle can be applicable to these particles if they are fermions, so 'trillions' can not gather in the same place

2 Collision is possible but the probability is extremely low
As I understand, the collision occurs at the Sypersymmetry breaking energy
Such virtual particles are very rare.

 

[heldervelez]

...

Here's what my copy of the paper says, in its last para:
"..."
May I ask how you read "major patch" into this?

quoting from the above paper
"Even though some of the puzzles discussed here may be resolved by more complete observations or astrophysical
effects, the possible requirement of more fundamental modifications of the CDM model remains valid.
...
This improved effectiveness could possibly be provided by a mild
evolution of Newton’s constant G (higher G at z > 0.5)"

in the first bold I read "major patch" and in the second bold I read "lets rewrite the more fundamental laws of physics".
An hipotetical evolution of G, of T, of alfa, of L and may others and combinations of those constants or magnitudes have been tried. I've found pappers on G and on alfa.

Triyng to mess with G without providing a mechanism for such change is data fit. But until now the pursue has been unfruitfull.