[Physics] Why are “heavier” particles harder to detect than “lighter” ones


Something I have read multiple times that I've never intuitively understood is that "heavier" particles are harder to detect than "lighter" ones… For example, I quote from Stephen Hawking's "The Grand Design" in relation to supersymmetry:

But various calculations that physicists have performed indicate that the partner particles corresponding to the particles we observe ought to be a thousand times as massive as a proton, if not even heavier. That is too heavy for such particles to have been seen in any experiments to date, but there is hope that such particles will eventually be created in the Large Hadron Collider in Geneva.

Could someone please explain, in simple terms, why heavy particles are harder to detect? Intuitively (to me, a non-physicist) it would seem that it should be the other way around, because a particle with more mass should interact more strongly with other matter.

Best Answer

They are harder to detect for mainly two reasons:

First, because they decay very quickly into lighter particles. Infact the heaviest elementary particle we know of ( top quark ) decay's so rapidly it is theoretically and technically impossible to measure it in any other way than indirectly through its decay products.

This poses another problem as to what statistical and theoretical basis one can with some certainty claim detection of such particles.

Another problem is that of production, since they have more mass, they require much more energy to produce, thus larger and more expensive accelerators.

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