# How does this formula relate to particle creation?

1. Feb 1, 2013

### AbsoluteZer0

Hi,

ΔEΔt ≥$\frac{h}{4\pi}$

How does this formula relate to particle creation? I understand that it is relevant to the uncertainty principle, but that is essentially all that I am aware of. Does this formula indicate that when a particle with energy 'E' exists for time 't' it then decays?

Thanks,

Last edited: Feb 1, 2013
2. Feb 1, 2013

### Staff: Mentor

Both are related to quantum physics, but I don't see a direct relation between particle creation and this uncertainty relation.
For short-living particles, the uncertainty relation gives them a natural width in their mass.

3. Feb 1, 2013

### The_Duck

What this formula means is that if a particle only exists for a short time $\Delta t$, then its energy is necessarily uncertain by an amount $\Delta E = h / 4 \pi \Delta t$. For example, the mass of the rho meson is nominally 770 MeV. However, the rho meson is extremely short-lived: $\Delta t \approx 4 \times 10^{-24}$ seconds, so we actually observe rho mesons with a range of masses, with the extent of that range being about $\Delta E = 145$ MeV. So it wouldn't be uncommon to observe a rho meson with mass 700 MeV, for instance.

See http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/parlif.html