TY - JOUR
T1 - Symmetry breaking and the decays ψ′ → J ψπ0(η) and J ψ → η(η′) γ
AU - Langacker, Paul
N1 - Funding Information:
The isospin violating decay 4' ~ 4 rr0 has recently been observed \[1,2\]b y the Crystal Ball and MARK II collaborations at SPEAR. The Crystal Ball group \[1\ ] finds a large branching ratio B(4' ~ 47r 0) = (0.08 -+ 0.02 + 0.02) %. They also fired B(4' ~ 4r/) = (2.06 + 0.10 -+ 0.58) %, somewhat lower than the old average \[3,4\] of (4.2 -+ 0.7) %. The ratio R =B(~b' ~ 47rO)/B(4 ' 4r/) is less subject to systematic uncertainties. The Crystal Ball result is \[1\]R = (39 -+ 10) × 10 -3. Similar results have been found by the MARK II group \[2\]. The first theoretical discussion of the 4' "~ ¢7r 0 decay was by Segre and Weyers \[5\]w, ho suggested that the decay could proceed via n°-r/mixing, as shown in fig. la. It was subsequently pointed out by Work supported in part by the Department of Energy under contracts DE-AC03-76SF00515 and EY-76-C-02-3071.
PY - 1980/3/10
Y1 - 1980/3/10
N2 - The theoretical mechanisms for the decays ψ′ → ψπ0 and ψ′ → ψη, which violate SU2 and SU3, respectively discussed. It is argued that symmetry breaking in the decay amplitudes may be as important as π0 -η -η′ mixing. The π0 -η mechanism ψ′ → ψν → ψπ0 leads to Γ(ψ′ → ψπ0) = (3.3±1.0) × 10-3 Γ(ψ′ → ψν), but this number may be enhanced by a factor as large as 12 by π0-η′ mixing and isospin violation in the decay amplitude. The related decays ψ → ηγ and ψ → η′γ are also discussed.
AB - The theoretical mechanisms for the decays ψ′ → ψπ0 and ψ′ → ψη, which violate SU2 and SU3, respectively discussed. It is argued that symmetry breaking in the decay amplitudes may be as important as π0 -η -η′ mixing. The π0 -η mechanism ψ′ → ψν → ψπ0 leads to Γ(ψ′ → ψπ0) = (3.3±1.0) × 10-3 Γ(ψ′ → ψν), but this number may be enhanced by a factor as large as 12 by π0-η′ mixing and isospin violation in the decay amplitude. The related decays ψ → ηγ and ψ → η′γ are also discussed.
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U2 - 10.1016/0370-2693(80)90971-5
DO - 10.1016/0370-2693(80)90971-5
M3 - Article
AN - SCOPUS:4243991831
VL - 90
SP - 447
EP - 450
JO - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
JF - Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
SN - 0370-2693
IS - 4
ER -