Question

Can pair production take place in vacuum ? Explain

Answer 1

Answer:

ɪɴ ᴛʜᴇ ᴇᴍᴘᴛʏ sᴘᴀᴄᴇ ʏᴏᴜ ᴄᴀɴɴᴏᴛ ᴅᴇғɪɴᴇ ᴀ ᴄᴇɴᴛᴇʀ ᴏғ ᴍᴀss. ᴏɴ ᴛʜᴇ ᴄᴏɴᴛʀᴀʀʏ ᴀ ᴘᴀɪʀ ᴘᴀʀᴛɪᴄʟᴇ-ᴀɴᴛɪᴘᴀʀᴛɪᴄʟᴇ ʜᴀs ᴀ ᴄᴏᴍ ᴏғ ɪᴛs ᴏᴡɴ. ... ɪғ ʏᴏᴜ ʜᴀᴠᴇ ᴢᴇʀᴏ ᴘʜᴏᴛᴏɴs, ʙᴜᴛ ᴊᴜsᴛ ᴠᴀᴄᴜᴜᴍ ғʟᴜᴄᴛᴜᴀᴛɪᴏɴs, ʏᴏᴜ ʜᴀᴠᴇ ɴᴏᴛ ᴇɴᴏᴜɢʜ ᴇɴᴇʀɢʏ ᴛᴏ ᴄʀᴇᴀᴛᴇ ʀᴇᴀʟ ᴘᴀʀᴛɪᴄʟᴇs, ʙᴜᴛ ᴏɴʟʏ ᴠɪʀᴛᴜᴀʟ ᴘᴀɪʀs..

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Answer 2

Explanation:

• Originally Answered: why does pair production cannot occur in vacuum?

• Photons, from which pairs are created, have both energy & momentum, neither of which can be zero. Since there is no frame of reference in which the photon momentum is zero, you then have a violation of conservation of momentum.

• Taking this requirement into account, we can anticipate that pair production cannot take place in empty space; something must absorb the momentum (p=h/l =hf/c) of the initial photon.