Antideuteron production in $\mathit{\Upsilon }(nS)$ decays and in $e^{+}{e}^{-}\to q\overline{q}$ at $\sqrt{s}\approx 10.58\mathrm{GeV}$

We present measurements of the inclusive production of antideuterons in $e^{+}{e}^{-}$ annihilation into hadrons at $\approx 10.58\mathrm{GeV}$ center-of-mass energy and in $\mathit{\Upsilon }(1S,2S,3S)$ decays. The results are obtained using data collected by the BABAR detector at the PEP-II electron-positron collider. Assuming a fireball spectral shape for the emitted antideuteron momentum, we find $\mathcal{B}(\mathit{\Upsilon }(1S)\to \overline{d}X)=(2.81\pm 0.49(\text{stat}{)}_{-0.24}^{+0.20}(\text{syst}))\times {10}^{-5}$, $\mathcal{B}(\mathit{\Upsilon }(2S)\to \overline{d}X)=(2.64\pm 0.11(\text{stat}{)}_{-0.21}^{+0.26}(\text{syst}))\times {10}^{-5}$, $\mathcal{B}(\mathit{\Upsilon }(3S)\to \overline{d}X)=(2.33\pm 0.15(\text{stat}{)}_{-0.28}^{+0.31}(\text{syst}))\times {10}^{-5}$, and $\sigma (e^{+}{e}^{-}\to \overline{d}X)=(9.63\pm 0.41(\text{stat}{)}_{-1.01}^{+1.17}(\text{syst})\mathrm{fb}$.

Figure 1

Normalized residuals of the combined $dE/dx$ for antideuteron candidates in the Onpeak $\mathit{\Upsilon }(2S)$ data sample, with fit PDFs superimposed. Entries have been weighted, as detailed in the text. The solid (blue) line is the total fit, the dashed (blue) line is the $\overline{d}$ signal peak, and the dotted (red) line is the background.

Figure 2

Measured antideuteron differential spectra in (a) $\mathit{\Upsilon }(2S)$, (b) $\mathit{\Upsilon }(3S)$, (c) $\mathit{\Upsilon }(1S)$ decays, and (d) $e^{+}{e}^{-}\to q\overline{q}$ at a c.m. energy of $\approx 10.58\mathrm{GeV}$. The points with inner (black) error bars give the measurements and their associated statistical uncertainties, the outer (red) error bars give the quadratic sum of the statistical and systematic uncertainties, and the dashed (blue) curves show the fit to Eq. (2). Subfigure (c) also includes the CLEO results with dashed error bars for comparison.