(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Mass of neutrino = 0

Mass of proton/neutron = 1 GeV

Mass of tau = 2 GeV

2. Relevant equations

Energy of neutrino in lab = e

Energy of neutrino in CM = e0

3. The attempt at a solution

In the centre of mass frame, we will take the momentum of the neutron to be e0/c, c = speed of light.

CoE in CM: e0 + sqrt(m_n^2*c^4 + e0^2) = (m_p + m_tau)c^2

this gives e0 =1.33 GeV

therefore the velocity of CM in lab frame = (e0/c)/(m_v + m_n) = e0/(c*m_n) = 1.33c > c.

Cannot find where I'm doing the mistake!!

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# Homework Help: Threshold Energy of neutrino

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