23-29 June 2019
Asia/Ho_Chi_Minh timezone
15th Rencontres du Vietnam

Recent Elastic and Total Cross-Section Measurements by TOTEM

Jun 25, 2019, 12:00 PM


Quy Nhon, Vietnam
Elastic Scattering and Total Cross Section Session 3


Mario Deile (CERN)


The TOTEM experiment at the interaction point 5 of the LHC has measured the total, elastic and inelastic proton-proton cross sections in a centre-of-mass energy range from 2.76 to 13 TeV, mostly in dedicated fills with special beam optics.

Most recently, TOTEM has performed a series of detailed measurements at $\sqrt{s}$ = 13 TeV. The total, elastic and inelastic proton-proton cross-sections were determined using the luminosity-independent method based on the optical theorem.
Elastic scattering data in the Coulomb-nuclear interference region, at squared four-momentum transfers down to |t| ~ 8 x $10^{-4}$ GeV$^{2}$ allowed the first measurement of the rho parameter at sqrt(s) = 13 TeV, where rho is the ratio between the real and the imaginary part of the nuclear elastic scattering amplitude at t = 0. This measurement, combined with the TOTEM total cross-section results, led to the exclusion of all the models classified and published by COMPETE. The rho and sigma_tot results obtained by TOTEM are compatible with
predictions of a colourless 3-gluon bound state exchange in the t-channel of proton-proton elastic scattering, as postulated by alternative theoretical models both in the Regge-like framework and in the modern QCD framework.
On the large |t| side the elastic differential cross-section measurement was
pushed to 4 GeV$^{2}$. Thanks to very high statistics, the dip-bump structure
between 0.4 and 0.8 GeV$^{2}$ was surveyed with unprecedented precision. At
higher |t|-values up to the end of the observed range no further structure
is present.
The presentation will conclude with an outlook on measurements planned for LHC Run 3.

Primary author

Presentation materials