Measurement of the forward charged-particle pseudorapidity density inppcollisions at √s = 7 TeV with the TOTEM experiment

The TOTEM experiment has measured the charged-particle pseudorapidity density dN(ch)/d eta in pp collisions at root s = 7TeV for 5.3 < |eta| < 6.4 in events with at least one charged particle with transverse momentum above 40MeV/c in this pseudorapidity range. This extends the analogous measurement performed by the other LHC experiments to the previously unexplored forward eta region. The measurement refers to more than 99% of non-diffractive processes and to single and double diffractive processes with diffractive masses above similar to 3.4GeV/c(2), corresponding to about 95% of the total inelastic cross-section. The dN(ch)/d eta has been found to decrease with |eta|, from 3.84 +/- 0.01(stat) +/- 0.37(syst) at |eta| = 5.375 to 2.38 +/- 0.01(stat) +/- 0.21(syst) at |eta| = 6.375. Several MC generators have been compared to data; none of them has been found to fully describe the measurement. Copyright CERN for the benefit of the TOTEM Collaboration. Published by the EPLA under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.