Pseudorapidity (η) distributions of charged particles produced in proton-proton collisions at a centre-of-mass energy of 8 TeV are measured in the ranges |η| < 2.2 and 5.3 < |η| < 6.4 covered by the CMS and TOTEM detectors, respectively. The data correspond to an integrated luminosity of L = 45 µb −1 . Measurements are presented for three event categories. The most inclusive category is sensitive to 91-96 % of the total inelastic proton-proton cross section. The other two categories are disjoint subsets of the inclusive sample that are either enhanced or depleted in single diffractive dissociation events. The data are compared to models used to describe high-energy hadronic interactions. None of the models considered provide a consistent description of the measured distributions.

The TOTEM experiment has made a precise measurement of the elastic proton-proton differential cross-section at the centre-of-mass energy √ s = 8 TeV based on a high-statistics data sample obtained with the β * = 90 m optics. Both the statistical and systematic uncertainties remain below 1 %, except for the t-independent contribution from the overall normalisation. This unprecedented precision allows to exclude a purely exponential differential cross-section in the range of fourmomentum transfer squared 0.027 < |t| < 0.2 GeV 2 with a significance greater than 7 σ. Two extended parametrisations, with quadratic and cubic polynomials in the exponent, are shown to be well compatible with the data. Using them for the differential cross-section extrapolation to t = 0, and further applying the optical theorem, yields total cross-section estimates of (101.5 ± 2.1) mb and (101.9 ± 2.1) mb, respectively, in agreement with previous TOTEM measurements.This article is dedicated to the memory of Prof. E. Lippmaa and Prof. M. Lo Vetere who passed away recently

This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC. The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. After introducing the physics studies that will most profit from the addition of these new detectors, we discuss in detail the optimization and the performance of the first TOF detector installed in the LHC in November 2015.

Proton-proton elastic scattering at the LHC energy of s = 7 TeV The TOTEM Collaboration, G. Antchev, P. Aspell et al.Measurement of proton-proton elastic scattering and total cross-section at The TOTEM Collaboration, G. Antchev, P. Aspell et al.-LHC optics measurement with proton tracks detected by the Roman pots of the TOTEM experiment The TOTEM Collaboration, G Antchev, P Aspell et al. Abstract -TOTEM has measured the differential cross-section for elastic proton-proton scattering at the LHC energy of √ s = 7 TeV analysing data from a short run with dedicated large-β * optics. A single exponential fit with a slope B = (20.1 ± 0.2 stat ± 0.3 syst ) GeV −2 describes the range of the four-momentum transfer squared |t| from 0.02 to 0.33 GeV 2 . After the extrapolation to |t| = 0, a total elastic scattering cross-section of (24.8 ± 0.2 stat ± 1.2 syst ) mb was obtained. Applying the optical theorem and using the luminosity measurement from CMS, a total proton-proton cross-section of (98.3 ± 0.2 stat ± 2.8 syst ) mb was deduced which is in good agreement with the expectation from the overall fit of previously measured data over a large range of center-of-mass energies. From the total and elastic pp cross-section measurements, an inelastic pp cross-section of (73.5 ± 0.6open access editor's choice 21002-p1The TOTEM Collaboration (G. Antchev et al.) Introduction. -The observation of the rise of the total cross-section with energy was one of the highlights at the ISR, the first CERN collider [1][2][3][4]. Some indirect indications for this unforeseen phenomenon had already come earlier from high-energy cosmic-ray showers [5][6][7]. A long series of total proton-antiproton cross-section measurements followed in the last decades both at the CERN SppS collider [8,9] and at the TEVATRON [10][11][12][13].In this letter, we report the first measurement of the total and elastic proton-proton cross-sections at the CERN Large Hadron Collider (LHC) using the optical theorem together with the luminosity provided by the CMS experiment [14,15]. With a dedicated beam optics configuration (β * = 90 m) TOTEM has measured the differential crosssection of elastic scattering for four-momentum transfer squared values |t| to 2 × 10 −2 GeV 2 , making the extrapolation to the optical point at |t| = 0 possible. This allows the determination of the elastic scattering cross-section as well as the total cross-section.

-At the LHC energy of √ s = 7 TeV, under various beam and background conditions, luminosities, and Roman Pot positions, TOTEM has measured the differential cross-section for proton-proton elastic scattering as a function of the four-momentum transfer squared t. The results of the different analyses are in excellent agreement demonstrating no sizeable dependence on the beam conditions. Due to the very close approach of the Roman Pot detectors to the beam center (≈ 5σ beam ) in a dedicated run with β * = 90 m, |t|-values down to 5 · 10 −3 GeV 2 were reached. The exponential slope of the differential elastic cross-section in this newly explored |t|-region remained unchanged and thus an exponential fit with only one constant B = (19.9±0.3) GeV −2 over the large |t|-range from 0.005 to 0.2 GeV 2 describes the differential distribution well. The high precision of the measurement and the large fit range lead to an error on the slope parameter B which is remarkably small compared to previous experiments. It allows a precise extrapolation over the non-visible cross-section (only 9%) to t = 0. With the luminosity from CMS, the elastic crosssection was determined to be (25.4 ± 1.1) mb, and using in addition the optical theorem, the total pp cross-section was derived to be (98.6 ± 2.2) mb. For model comparisons the t-distributions are tabulated including the large |t|-range of the previous measurement (TOTEM Collaboration (Antchev G. et al.), EPL, 95 (2011) 41001).open access