How do I to disable the x or y axis in a7 physics ? Is possible ?

thats impossible

No, it´s not.
Look at ackphysX.h for these:

#define NX_BF_FROZEN_POS_X (1<<1) // Enable/disable freezing for this body/actor.
#define NX_BF_FROZEN_POS_Z (1<<2)
#define NX_BF_FROZEN_POS_Y (1<<3)

A7.

Many apologies.

But maybe you can use some invisible walls to restrict the entities.
Depends on your project, of course.