Measurement of the total cross section from elastic scattering in  pp  collisions at s = 8   TeV with the ATLAS detector

Aaboud, M; Aad, G; Abbott, B; Abdallah, J; Abdinov, O; Abeloos, B; Aben, R; AbouZeid, O S; Abraham, N L; Abramowicz, H; Abreu, H; Abreu, R; Abulaiti, Y; Acharya, B S; Adachi, S; Adamczyk, L; Adams, D L; Adelman, J; Adomeit, S; Adye, T; Affolder, A A; Agatonovic-Jovin, T; Agricola, J; Aguilar-Saavedra, J A; Ahlen, S P; Ahmadov, F; Aielli, G; Akerstedt, H; Åkesson, T P A; Akimov, A V; Alberghi, G L; Albert, J

Measurement of the total cross section from elastic scattering in pp collisions at s = 8 TeV with the ATLAS detector

Journal Article

2016

Journal Title

Physics Letters, B

Link to Journal

https://dx.doi.org/10.1016/j.physletb.2016.08.020

Department

Department of Physics

Faculty

Faculty of Science

Abstract

A measurement of the total $pp$ cross section at the LHC at $sqrt{s}=8$ TeV is presented. An integrated luminosity of $500$ $mu$b${-1}$ was accumulated in a special run with high-$beta{star}$ beam optics to measure the differential elastic cross section as a function of the Mandelstam momentum transfer variable $t$. The measurement is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in the $-t$ range from $0.014$ GeV$2$ to $0.1$ GeV$2$ to extrapolate $trightarrow 0$, the total cross section, $sigma_{mathrm{tot}}(pprightarrow X)$, is measured via the optical theorem to be: $sigma_{mathrm{tot}}(pprightarrow X) = {96.07} ; pm 0.18 ; ({{stat.}}) pm 0.85 ; ({{exp.}}) pm 0.31 ; ({extr.}) ; {mb} ;,$ where the first error is statistical, the second accounts for all experimental systematic uncertainties and the last is related to uncertainties in the extrapolation $trightarrow 0$. In addition, the slope of the exponential function describing the elastic cross section at small $t$ is determined to be $B = 19.74 pm 0.05 ; ({{stat.}}) pm 0.23 ; ({{syst.}}) ; {GeV}{-2}$.