We perform an analysis of the three-pion system with quantum numbers JPC=1++ produced in the weak decay of τ leptons. The interaction is known to be dominated by the axial meson a1(1260). We build a model based on approximate three-body unitary and fix the free parameters by fitting it to the ALEPH data on τ-→π-π+π-ντ decay. We then perform the analytic continuation of the amplitude to the complex energy plane. The singularity structures related to the ππ subchannel resonances are carefully addressed. Finally, we extract the a1(1260) pole position mp(a1(1260))-iΓp(a1(1260))/2 with mp(a1(1260))=(1209±4-9+12) MeV, Γp(a1(1260))=(576±11-20+89) MeV.
Pole position of the a1(1260) from τ -decay / Mikhasenko, M.; Pilloni, A.; Jackura, A.; Albaladejo, M.; Fernández-Ramírez, C.; Mathieu, V.; Nys, J.; Rodas, A.; Ketzer, B.; Szczepaniak, A. P.. - In: PHYSICAL REVIEW D. - ISSN 2470-0010. - 98:9(2018). [10.1103/PhysRevD.98.096021]
Pole position of the a1(1260) from τ -decay
Pilloni, A.;
2018
Abstract
We perform an analysis of the three-pion system with quantum numbers JPC=1++ produced in the weak decay of τ leptons. The interaction is known to be dominated by the axial meson a1(1260). We build a model based on approximate three-body unitary and fix the free parameters by fitting it to the ALEPH data on τ-→π-π+π-ντ decay. We then perform the analytic continuation of the amplitude to the complex energy plane. The singularity structures related to the ππ subchannel resonances are carefully addressed. Finally, we extract the a1(1260) pole position mp(a1(1260))-iΓp(a1(1260))/2 with mp(a1(1260))=(1209±4-9+12) MeV, Γp(a1(1260))=(576±11-20+89) MeV.| File | Dimensione | Formato | |
|---|---|---|---|
|
Pilloni_Pole-position.pdf
accesso aperto
Tipologia:
Versione editoriale (versione pubblicata con il layout dell'editore)
Licenza:
Creative commons
Dimensione
1.09 MB
Formato
Adobe PDF
|
1.09 MB | Adobe PDF |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
