Abstract
The TOTEM collaboration has measured the proton–proton total cross section at sqrt{s}=13~hbox {TeV} with a luminosity-independent method. Using dedicated beta ^{*}=90~hbox {m} beam optics, the Roman Pots were inserted very close to the beam. The inelastic scattering rate has been measured by the T1 and T2 telescopes during the same LHC fill. After applying the optical theorem the total proton–proton cross section is sigma _mathrm{tot}=(110.6~pm ~3.4) mb, well in agreement with the extrapolation from lower energies. This method also allows one to derive the luminosity-independent elastic and inelastic cross sections: sigma _mathrm{el}=(31.0~pm ~1.7)~hbox {mb} and sigma _mathrm{inel}=(79.5~pm ~1.8)~hbox {mb}.
Highlights
This paper presents the first measurement of th√e total proton– proton cross section at a center of mass energy s = 13 TeV; the measurement is luminosity independent
The TOTEM experimental setup consists of two inelastic telescopes T1 and T2 to detect charged particles coming from inelastic pp collisions and the Roman Pot detectors (RP) to detect elastically scattered protons at very small angles
The inelastic telescopes are placed symmetrically on both sides of Interaction Point 5 (IP5): the T1 telescope is based on cathode strip chambers (CSCs) placed at ±9 m and covers the pseudorapidity range 3.1 ≤ |η| ≤ 4.7; the T2 telescope is based on gas electron multiplier (GEM) chambers placed at ±13.5 m and covers the pseudorapidity range 5.3 ≤ |η| ≤ √6.5
Summary
The TOTEM experimental setup consists of two inelastic telescopes T1 and T2 to detect charged particles coming from inelastic pp collisions and the Roman Pot detectors (RP) to detect elastically scattered protons at very small angles. As the fraction of events with all final state particles beyond the instrumented region has to be estimated using phenomenological models, the excellent acceptance in TOTEM minimizes the dependence on such models and provides small uncertainty on the inelastic rate measurement. The Roman Pot (RP) units used for the present measurement are located on both sides of the IP at distances of ±213 m (near) and ±220 m (far) from IP5. The horizontal RP overlaps with the two verticals and allows for a precise relative alignment of the detectors within the unit. A complete description of the TOTEM detector is given in [9,11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
