Elastic differential cross-section $\mathrm{d}\ddot{I}ƒ/\mathrm{d}t$ at $\sqrt{s}=$2.76 TeV and implications on the existence of a colourless 3-gluon bound state

Abstract

The proton-proton elastic differential cross section $\mathrm{d}\ddot{I}ƒ/\mathrm{d}t$ has been measured by the TOTEM experiment at $\sqrt{s}=2.76$ TeV energy with $β^{*}=11$ m beam optics. The Roman Pots were inserted to 13 times the transverse beam size from the beam, which allowed to measure the differential cross-section of elastic scattering in a range of the squared four-momentum transfer ($|t|$) from $0.36$ GeV${}^2$ to $0.74$ GeV${}^2$. The differential cross-section can be described with an exponential in the $|t|$-range between $0.36$ GeV${}^2$ and $0.54$ GeV${}^2$, followed by a diffractive minimum (dip) at $|t_{\mathrm{dip}}|=0.61\pm 0.03$ GeV${}^2$ and a subsequent maximum (bump). The ratio of the $\mathrm{d}\ddot{I}ƒ/\mathrm{d}t$ at the bump and at the dip is $1.7\pm 0.2$. When compared to the $\mathrm{p}\bar{\mathrm{p}}$ measurement of the D0 experiment at $\sqrt{s}=1.96$ TeV, a significant difference can be observed. Under the condition that the effects due to the energy difference between TOTEM and D0 can be neglected, the result provides evidence for a colourless 3-gluon bound state exchange in the $t$-channel of the proton-proton elastic scattering.

75 authors, 17 pages, 10 figures, 3 tables