TOTEM, detector and physics

The TOTEM (TOTal cross section, Elastic scattering and diffractiondissociation Measurement at the LHC) experiment, located at theinteraction point 5 of the LHC, has measured the total, elastic andinelastic proton-proton cross-sections, using a luminosity independentmethod, based on the optical theorem, in a center-of-mass energy rangefrom 2.76 to 13 TeV. The elastic scattering was investigated in a widerange of the squared four-momentum transfer $|t|$ allowing studyof the Coulomb-nuclear interference region down to $|t| \sim 8\times10^{-4}$ GeV$^{2}$. This made possible the first measurement of the $\rho$parameter at $\sqrt{s} = 13$ TeV, $\rho$ being the ratio between the realand the imaginary part of the nuclear elastic scattering amplitude at$t = 0$. This measurement, combined with the total cross-sectionresults, led to the exclusion of all the models classified andpublished by the COMPETE Collaboration. The results obtained by TOTEMare indeed compatible with predictions of a colourless 3-gluon boundstate exchange in the t-channel of proton-proton elastic scattering,as postulated by alternative theoretical models both in the Regge-likeframework and in the modern QCD framework.In this contribution the TOTEM experiment detectors and results willbe described, along with the actual experiment status, the futurephysics program for the LHC Run~3.