Elastic differential cross-section measurement at $\sqrt{s}=13$ TeV by TOTEM

Abstract

The TOTEM collaboration has measured the elastic proton-proton differential cross section $\mathrm{d}\ddot{I}ƒ/\mathrm{d}t$ at $\sqrt{s}=13$ TeV LHC energy using dedicated $β^{*}=90$ m beam optics. The Roman Pot detectors were inserted to 10$\ddot{I}ƒ$ distance from the LHC beam, which allowed the measurement of the range $[0.04$ GeV${}^2$$;4$GeV${}^2$$]$ in four-momentum transfer squared $|t|$. The efficient data acquisition allowed to collect about 10${}^9$ elastic events to precisely measure the differential cross-section including the diffractive minimum (dip), the subsequent maximum (bump) and the large-$|t|$ tail. The average nuclear slope has been found to be $B=(20.40\pm 0.002^{\mathrm{stat}}\pm 0.01^{\mathrm{syst}})$GeV${}^{-2}$ in the $|t|$-range $0.04$GeV${}^2$ to $0.2$GeV${}^2$. The dip position is $|t_{\mathrm{dip}}|=(0.47\pm 0.004^{\mathrm{stat}}\pm 0.01^{\mathrm{syst}})$GeV${}^2$. The differential cross section ratio at the bump vs. at the dip $R=1.77\pm 0.01^{\mathrm{stat}}$ has been measured with high precision. The series of TOTEM elastic pp measurements show that the dip is a permanent feature of the pp differential cross-section at the TeV scale.

76 authors, 20 pages, 11 figures, 5 tables