On Friday, we had our Physics test. We (the tenth grade students) have the basic introduction to Radioactivity and a few nuclear reactions in our syllabus. In the test, the following question was asked:
Identify $x$ in the following nuclear reaction and state its mass:
$_{12}^{24}Mg + x \rightarrow _{11}^{23}Na + _{1}^{1}H$
Here's what I did:
I noticed that the sum of the masses and atomic numbers of the reactants and products is constant:
Right Hand side (without $x$):
Total sum of mass = 24
Total sum of atomic numbers = 12Left Hand side:
Total mass = 23 + 1 = 24
Total sum of atomic numbers = 11 + 1 = 12
Since there is no difference in mass or charge, I wrote that $x$ is a massless, chargeless, photon or $\gamma$ particle.
But the source of confusion:
After the test, a few of my friends said the $x$ is an anti-neutrino ($\bar{\nu}$), which is also a massless, chargeless particle. But a $\bar{\nu}$ is released only during the conversion of a neutron right?
$_{0}^{1}n \rightarrow _{+1}^{1}p + _{-1}^{0}e + \bar{\nu}$
How is this applicable in this regard?
Is either of the two answers correct?
If so, which is the right one? If not, what is the correct answer?