My current research involves making a prediction for data collected by the TOTEM experiment at the LHC. The experiment is primarily designed to measure the total inelastic and elastic scattering cross sections, and accordingly all the results I've seen from the TOTEM collaboration show $\sigma_\text{inel}(\sqrt{s})$ or $\sigma_\text{el}(\sqrt{s})$. But the calculation I'm doing outputs (essentially) the differential cross section $\frac{\mathrm{d}^3\sigma}{\mathrm{d}^2 \mathbf{p}_\perp \mathrm{d}\eta}$ at a specific value of the pseudorapidity $\eta$ and transverse momentum $p_\perp$.

Is TOTEM's T2 detector capable of recording $p_\perp$ and $\eta$ for its detected events, so that it could bin them and thus report the differential cross section? Or is it only capable of measuring total event counts? In the latter case it wouldn't be much use to make a prediction of the differential cross section; I'd have to integrate to get the total cross section.

  • $\begingroup$ David, it looks like they may have some limited sensitivity to scattering angle, but little ability to resolve either $s$ or $\eta$. I'd suggest getting their technical design report (likely available on arXiv) and looking in there. $\endgroup$ – dmckee --- ex-moderator kitten Jun 11 '13 at 19:43
  • $\begingroup$ Hmmm...I see they are using a GEM for T2 which implies very good spacial resolution. What I can't determine on the web site is if they have an analyzing magnet. Without one you are stuck with scattering angle (but better resolution than I initially thought). With a magnet they may be able to resolve momentum as well which implies getting both $s$ and $\eta$. $\endgroup$ – dmckee --- ex-moderator kitten Jun 11 '13 at 19:49
  • $\begingroup$ Ah, now that's the kind of thing I wouldn't have known. (theorist == clueless about detector components) I'll try to track down that report when I have some more time. $\endgroup$ – David Z Jun 11 '13 at 19:50

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