# Natural unit conversions within HEP

In HEP, with the $$\hbar = c = 1 \;.$$ We have $$\hbar c = 200 \;\mathrm{MeV \cdot fm}$$

1 second is equivalent to $$10^{-25}$$ GeV. How these relations are used to convert seconds to GeV, GeV to seconds.

• Punctuation related to block-set equations is generally typeset on the same line as the equation, and it is typical to use either a thin-space (\,) or a central dot (\cdot) to separate unit symbols. – dmckee Oct 24 at 16:07
• You have studied WP and found it lacking? – Cosmas Zachos Oct 24 at 18:51
• – anna v Oct 25 at 4:03

In natural units, seconds and gigaelectronvolts (i.e., time and energy) are inversely related. You cannot convert GeV to seconds, but you can convert GeV$$^{-1}$$ to seconds.

The value of the reduced Planck constant is

$$\hbar=1.055\times 10^{-34}\text{ J}\cdot\text{s}=6.582\times 10^{-25}\text{ GeV}\cdot\text{s}.$$

If you use units where it is $$1$$, then you are taking

$$1\text{ GeV}^{-1}=6.582\times 10^{-25}\text{ s}.$$

• formulas missing – anna v Oct 25 at 3:58
• in my browser There is nothing after t"reduced Plamnck constant" nor after "you are taking". I am using Chrome. – anna v Oct 26 at 4:15
• @annav They show just fine for me. Can you see formulas in other posts, or is it just this one? – Chris Oct 26 at 4:34
• This is the first time I have observed this. I will try Firefox. – anna v Oct 26 at 4:36
• On Firfox it is OK !!!!! – anna v Oct 26 at 4:39