Elastic differential cross-section measurement at √s=13 TeV by TOTEM

The TOTEM collaboration has measured the elastic proton-proton differential cross section d σ/ d t at s=13 TeV LHC energy using dedicated β∗= 90 m beam optics. The Roman Pot detectors were inserted to 10σ distance from the LHC beam, which allowed the measurement of the range [0.04 GeV2; 4 GeV2] in four-momentum transfer squared |t|. The efficient data acquisition allowed to collect about 109 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±0.002stat±0.01syst)GeV- 2 in the |t|-range 0.04–0.2 GeV2. The dip position is |tdip|=(0.47±0.004stat±0.01syst)GeV2. The differential cross section ratio at the bump vs. at the dip R= 1.77 ± 0. 01 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.