Exploring detection of nuclearites in a large liquid scintillator neutrino detector

We take the JUNO experiment as an example to explore nuclearites in the future large liquid scintillator detector. Comparing to the previous calculations, the visible energy of nuclearites across the liquid scintillator will be reestimated for the liquid scintillator based detector. Then the JUNO sensitivities to the nuclearite flux are presented. It is found that the JUNO projected sensitivities can be better than $7.7\times {10}^{-17}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}{\mathrm{sr}}^{-1}$ for the nuclearite mass $10^{15}\mathrm{GeV}\le M\le 10^{24}\mathrm{GeV}$ and initial velocity ${10}^{-4}\le {\beta }_0\le {10}^{-1}$ with a 20 year running. Note that the JUNO will give the most stringent limits for downgoing nuclearites with $1.6\times 10^{13}\mathrm{GeV}\le M\le 4.0\times 10^{15}\mathrm{GeV}$ and a typical galactic velocity ${\beta }_0={10}^{-3}$.

Figure 1

The maximal zenith angles ${\theta }_{\max }$ below which the local velocity of nuclearite satisfies ${\beta }_1>0$ (solid lines) and ${\beta }_1>{\beta }_{\min }$ (dashed lines) for 5 typical initial velocities ${\beta }_0$ at the ground level. In Sec. 4, we shall describe the minimal local velocity ${\beta }_{\min }$.

Figure 2

The modeled photon electron efficiency per photon as a function of the wavelength $\lambda$.

Figure 3

Left panel: the visible energy of nuclearite per unit track length $d{E}_{\text{vis}}/dx$ as a function of nuclearite mass for 5 typical ${\beta }_1$; Right panel: the ratio of $d{E}_{\text{vis}}/dx$ and $dE/dx$ as a function of ${\beta }_1$.

Figure 4

The minimal local velocity ${\beta }_{\min }$ above which nuclearites can satisfy the assumed JUNO trigger.

Figure 5

The JUNO 90% C.L. flux upper limits to the all direction (left) and downgoing (right) nuclearites with the local velocity ${\beta }_1>{\beta }_{\min }$ and the effective LS radius $R_{\mathrm{eff}}=17.52\mathrm{m}$ for a 20 yr running. The black and red dotted lines describe the JUNO most optimistic limits with ${\beta }_1>0$ and $R_{\mathrm{eff}}=17.7\mathrm{m}$ in the initial velocity ${\beta }_0={10}^{-3}$ case.