# The time between when the neutrinos are emitted in double-beta decay?

• A
Double-beta decay will emit two neutrinos.
But, are they simultaneously released or separated?

ohwilleke

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mfb
Mentor
Yes, they are emitted at the same time.

There are also many isotopes that will do a normal beta decay, where the produced nucleus will do another beta decay later, but that is not called double beta decay then.

ohwilleke and jedishrfu
Yes, they are emitted at the same time.

There are also many isotopes that will do a normal beta decay, where the produced nucleus will do another beta decay later, but that is not called double beta decay then.
I am serious in doubt "the same time". To be emitted at the same time is really a magic unless there are some physical mechanism to make them, otherwise "the same time" only means the instrument time resolution. If you have better instrument you will be able to detect they are NOT at the same time.

mfb
Mentor
To be emitted at the same time is really a magic unless there are some physical mechanism to make them
That physical mechanism is the double beta decay.

ohwilleke
Orodruin
Staff Emeritus
Homework Helper
Gold Member
The entire point with double beta decay is that the parent nucleus energetically cannot undergo single beta decay.

ohwilleke
The entire point with double beta decay is that the parent nucleus energetically cannot undergo single beta decay.
Are you sure?
What is the decay energy and branching fraction of calcium 48 single beta decay to scandium 48?

arivero
Orodruin
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Are you sure?
What is the decay energy and branching fraction of calcium 48 single beta decay to scandium 48?
That is something of an anomaly where single beta decay is allowed but not very favourable energetically compared to the double beta decay. However, the double decay is a higher order process. Together these effects happen to give similar decay widths for the two types of decay but it is not the general situation for double beta decaying nuclei.

ohwilleke
Staff Emeritus
2019 Award
There are two decays 48Ca -> 48Sc and 96Zr -> 96Mo where beta decay is almost but not quite energetically forbidden. However, the rates for these processes are substantially lower than for double beta decay: around 1000 for calcium and much larger for zirconium.

vanhees71