A search for a dark baryon is performed for the first time in the two-body decay Ξ−→π−+invisible using (10.087 ± 0.044) × 109 J / ψ events collected at a center-of-mass energy of s=3.097GeV with the BESIII detector at the BEPCII collider. No significant signal is observed, and the 90% (95%) confidence level upper limits on the branching fraction B(Ξ−→π−+invisible) are determined to be 4.2×10−5 (5.2×10−5), 6.9×10−5 (8.4×10−5), 6.5×10−4 (7.6×10−4), 1.1×10−4 (1.3×10−4) and 4.5×10−5 (5.5×10−5), under the dark baryon mass hypotheses of 1.07 GeV/ c 2, 1.10 GeV/ c 2, mjavax.xml.bind.JAXBElement@2eba2eaf (1.116 GeV/ c 2), 1.13 GeV/ c 2, and 1.16 GeV/ c 2, respectively. The constraints obtained on the Wilson coefficients Cus,sL and Cus,sR are more stringent than the previous limits derived from the LHC searches for the colored mediators.
Search for a dark baryon in the Ξ− → 𝜋− + invisible decay
Garzia, I.;Melendi, F. M.;
2026
Abstract
A search for a dark baryon is performed for the first time in the two-body decay Ξ−→π−+invisible using (10.087 ± 0.044) × 109 J / ψ events collected at a center-of-mass energy of s=3.097GeV with the BESIII detector at the BEPCII collider. No significant signal is observed, and the 90% (95%) confidence level upper limits on the branching fraction B(Ξ−→π−+invisible) are determined to be 4.2×10−5 (5.2×10−5), 6.9×10−5 (8.4×10−5), 6.5×10−4 (7.6×10−4), 1.1×10−4 (1.3×10−4) and 4.5×10−5 (5.5×10−5), under the dark baryon mass hypotheses of 1.07 GeV/ c 2, 1.10 GeV/ c 2, mjavax.xml.bind.JAXBElement@2eba2eaf (1.116 GeV/ c 2), 1.13 GeV/ c 2, and 1.16 GeV/ c 2, respectively. The constraints obtained on the Wilson coefficients Cus,sL and Cus,sR are more stringent than the previous limits derived from the LHC searches for the colored mediators.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
