6533b7dbfe1ef96bd126f79f
RESEARCH PRODUCT
Triangle mechanism in τ → f1(1285)πντ decay
Eulogio OsetLuis Rocasubject
PhysicsNuclear and High Energy PhysicsMass distribution010308 nuclear & particles physicsPropagatorState (functional analysis)Coupling (probability)01 natural sciencesResonance (particle physics)lcsh:QC1-999Distortion (mathematics)Loop (topology)Singularity0103 physical sciencesAtomic physics010306 general physicslcsh:Physicsdescription
Abstract We show that the τ − decay into f 1 ( 1285 ) π − ν τ is dominated by a triangle loop mechanism with K ⁎ , K ¯ ⁎ and K (or K ¯ ) as internal lines, which manifests a strong enhancement reminiscent of a nearby singularity present in the narrow K ⁎ limit and the near K ¯ ⁎ K ⁎ threshold of the internal K ⁎ propagators. The f 1 ( 1285 ) is then produced by its coupling to the K ⁎ K ¯ and K ¯ ⁎ K which is obtained from a previous model where this resonance was dynamically generated as a molecular K ⁎ K ¯ (or K ¯ ⁎ K ) state using the techniques of the chiral unitary approach. We make predictions for the f 1 π mass distribution which significantly deviates from the phase-space shape, due to the distortion caused by the triangle mechanism and the K ⁎ K ¯ threshold. We find a good agreement with the experimental value within uncertainties for the integrated partial decay width, which is a clear indication of the importance of the triangle mechanism in this decay and supports the dynamical origin of the f 1 ( 1285 ) as a K ⁎ K ¯ and K ¯ ⁎ K molecular state.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2018-07-01 | Physics Letters B |