Discovery potential of stable and near-threshold doubly heavy tetraquarks at the LHC

Understand

We study the LHC discovery potential of the double-bottom tetraquarks $bb \bar u \bar d$, $bb \bar u \bar s$ and $bb \bar d \bar s$, the lightest of which having $J^P=1^+$, called $T^{\{bb\}}_{[\bar u \bar d]}$, $T^{\{bb\}}_{[\bar u \bar s]}$ and $T^{\{bb\}}_{[\bar d \bar s]}$, are expected to be stable against strong decays.

• Employing the Monte Carlo generators MadGraph5$\_$aMC@NLO and Pythia6, we simulate the process $pp\to \bar b b\bar b b$ and calculate the $b b$-diquark jet configurations, specified by the invariant mass interval $m_{bb} < M_{T^{\{bb\}}_{[\bar q \bar q']}} + \Delta M$.
• Estimates of $\Delta M$ from the measured product $\sigma(pp \to B_c^+ +X){\cal B}(B_c^+\to J/\psi\pi^+)$ are presented and used to to get the $b b$-diquark jet cross sections in double-bottom hadrons $\sigma(pp \to H_{\{bb\}} +X)$, where $H_{\{bb\}} $ represent tetraquarks and baryons.
• This is combined with the LHCb data on the fragmentation $b \to \Lambda_b$ and $b \to B$ to obtain $\sigma(pp\to T^{\{bb\}}_{[\bar u\bar d]} +X) = (2.4 ^{+0.9}_{-0.6})\ \text{nb} $, and about a half of this for the $T^{\{bb\}}_{[\bar{u}\bar{s}]}$ and $T^{\{bb\}}_{[\bar d \bar s]}$.