I am reading an article on experimental nuclear physics. The article is about deuteron and triton production in Pb + Pb collisions. In the article they mention the coalescence factor which is given by:(adsbygoogle = window.adsbygoogle || []).push({});

[itex]B_{A}=A\frac{2s_{A}+1}{2^{A}}R^{N}_{np}\left(\frac{h^{3}}{m_{p}\gamma V}\right)^{A-1}[/itex]

The coalescence factor has something to do with the formation of light clusters A(Z,N). So A is the mass number of the cluster, the R_np thing is the ratio of neutrons to protons participating in the collision, gamma is just the lorentz factor related to the velocity of the cluster and V is the volume of of particles at freeze-out (after hadronization, when there are no more strong interactions between the nucleons). I don't know what s_A is though. I have worked out the units for A = 2 to be:

[itex]s_{A}\cdot \frac{ev^{2}s}{m}+\frac{ev^{2}s}{m}[/itex]

But i don't know the units of s_A. I was hoping for this to turn out unit-less, since it could then be interpreted as a sort of probability of a cluster A(Z,N) to form. Now i'm not sure what it is.

I apologize if this post was supposed to go in homework. Technically it is a sort of homework question, since i am supposed to present the article as an exam tomorrow. But i figured that there was a bigger chance that someone could help me with this on the HEP board.

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# What is the coalescence factor?

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