Probing Gluon Bose Correlations in Deep Inelastic Scattering

We study correlations originating from the quantum nature of gluons in a hadronic wave function. Bose-Einstein correlation between identical particles lead to the enhancement in the number of pairs of gluons with the same quantum numbers and small relative momentum. We show that these preexisting correlations can be probed in deep inelastic scattering experiments at high energy. Specifically, we consider diffractive dijet plus a third jet production. The azimuthal dependence displays a peak at the zero relative angle between the transverse momentum imbalance of the photon-going dijet and the transverse momentum of the hadron-going jet. Our calculations explicitly show that the peak originates from Bose enhancement. Comparing electron-proton to electron-nucleus collisions, we demonstrate that the nuclear target enhances the relative strength of the peak. With the future high luminosity electron-ion collider the proposed measurements of gluon Bose enhancement become experimentally feasible.

Figure 1

Schematic diagram showing the trijet production in ${\gamma }^{*}N$ collisions. Bose-Einstein correlations in the hadron wave function lead to the increase in the cross section of the trijet production, when the transverse momenta ${\mathbf{p}}_3\approx \pm ({\mathbf{p}}_1+{\mathbf{p}}_2)$.

Figure 2

The normalized trijet correlation as a function of the azimuthal angle between the vector of the momentum imbalance of the photon-going dijet $\mathbf{\Delta }$ and the momentum of the nucleus going jet ${\mathbf{p}}_3$. The magnitudes of both vectors are selected to be equal $|\mathbf{\Delta }|=|{\mathbf{p}}_3|=10\mathrm{GeV}$ and $p_1=10\mathrm{GeV}$, $Q_s=2\mathrm{GeV}$, $Q=1\mathrm{GeV}$.

Figure 3

The input parameters are the same as in Fig. 2 with $p_2=2\mathrm{GeV}$, but varying the ultraviolet cutoff in the momentum integrals. This illustrates that the peak at $\theta =0$ originates in the momentum region where $\mathbf{k}\approx -\mathrm{\Delta }$ and thus is indeed due to the Bose-Einstein correlations.

Figure 4

The normalized trijet correlation for different values of the saturation scales.