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Observation of a Near-Threshold Structure in the <math><msup><mi>K</mi><mo>+</mo></msup></math> Recoil-Mass Spectra in <math><mrow><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>−</mo></mrow></msup><mo>→</mo><msup><mrow><mi>K</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>(</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>−</mo></mrow></msubsup><msup><mrow><mi>D</mi></mrow><mrow><mo>*</mo><mn>0</mn></mrow></msup><mo>+</mo><msubsup><mrow><mi>D</mi></mrow><mrow><mi>s</mi></mrow><mrow><mo>*</mo><mo>−</mo></mrow></msubsup><msup><mrow><mi>D</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>)</mo></mrow></math>
- Source :
- Physical Review Letters
- Publication Year :
- 2021
- Publisher :
- APS, 2021.
-
Abstract
- We report a study of the processes of e+e−→K+Ds−D*0 and K+Ds*−D0 based on e+e− annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb−1. An excess of events over the known contributions of the conventional charmed mesons is observed near the Ds−D*0 and Ds*−D0 mass thresholds in the K+ recoil-mass spectrum for events collected at s=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5−2.6+1.8±2.1) MeV/c2 and (12.8−4.4+5.3±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into Ds−D*0 and Ds*−D0. However, the properties of the excess need further exploration with more statistics.
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Physical Review Letters
- Accession number :
- edsair.od......3000..4c9f5953cac73e0c4b0a576b3432b363