REVIEW 4 cited by
On the nature of a₁(1420)
Not yet reviewed by Pith; the record is open.
This paper has not been read by Pith yet. Machine review is queued; the pith claim, tier, and objections will appear here once it completes.
SPECIMEN: schema-true, not a live event
T0 review · schema-true
One-sentence machine reading of the paper's core claim.
pith:XXXXXXXX · record.json · timestamp
On the nature of a₁(1420)
read the original abstract
The resonance-like signal with axial-vector quantum numbers $J^{PC}=1^{++}$ at a mass of $1420\,$MeV and a width of $140\,$MeV, recently observed by the COMPASS and VES experiments in the $f_0(980)\pi$ final state and tentatively called $a_1(1420)$, is discussed. Instead of a genuine new meson, we interpret this signal as a dynamical effect due to a singularity (branching point) in the triangle diagram formed by the processes $a_1(1260) \to K^\star \bar{K}$, $K^\star\to K\pi$, and $K \bar{K} \to f_0(980)$ (+ c.c). The amplitude for this diagram is calculated. The result exhibits a peak in the intensity with a sharp phase motion with respect to the dominant $a_1(1260) \to \rho \pi$ $S$-wave decay, in good agreement with the data. The branching ratio of $a_1(1260)\to f_0(980)\pi$ via the triangle diagram is estimated and compared to the dominant decay $a_1(1260)\to\rho\pi$.
Forward citations
Cited by 4 Pith papers
-
The $a_1(1420)$ in a Unitary Coupled-Channel Three-Body Approach
Nine-channel unitary three-body fits to COMPASS lineshapes reproduce the a1(1420) enhancement by triangle singularity without requiring a genuine a1(1420) pole.
-
Three-body unitary determination of the $f_1(1285)$ and $f_1(1420)$ pole positions
Fitting a spectator-isobar three-body unitary amplitude to BESIII K0S K0S pi0 data yields poles at (1277±2±1)-i(12±1±0) MeV for f1(1285) and (1435±2±7)-i(40±2±1) MeV for f1(1420), with the latter traced to a K Kbar* q...
-
The $a_1(1420)$ in a Unitary Coupled-Channel Three-Body Approach
Unitary coupled-channel three-body model fitted to COMPASS data reproduces the a1(1420) enhancement via triangle singularity, indicating no genuine resonance pole is required.
-
Effects of Final State Interactions on Landau Singularities
Triangle singularities mimicking resonances are analyzed in the presence of final-state rescattering using Landau equations and a scattering formalism enforcing two- and three-body unitarity.
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.