The reaction $e^+e^−→e^+e^−π^0π^0$ has been analyzed using 97pb$^{−1}$ of data taken with the Crystal Ball detector at the DESY $e^−e^+$ storage ring DORIS II at beam energies around 5.3 GeV. For the first time we have measured the cross section for $γγ→π^0π^0$ for π0π0 mvariant masses ranging from threshold to about 2 GeV. We measure an approximately flat cross section of about 10 nb for W=$mπ^0π^0<0.8$ GeV, which is below 0.6 GeV, in good agreement with a theoretical prediction based on an unitarized Born-term model. At higher invariant masses we observe formation of the f2(1270) resonance and a hint of the f0(975). We deduce the following two-photon widths: $Γγγ(f2(1270))=3.19±0.16±0.29$ 0.28 keV and $Γγγ(f0(975))<0.53 keV$ at 90% C.L. T...
Using the Crystal Ball detector at the DORIS II e+e- storage ring, we measure the \u3b7\u3c0 0\u3c0 ...
The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ...
The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ...
The reaction $e^+e^−→e^+e^−π^0π^0$ has been analyzed using 97pb$^{−1}$ of data taken with the Crysta...
The reaction e+e- -> e+e- pi0 pi0 has been analyzed using 97 pb-1 of data taken with the Crystal Bal...
The reaction e+e- -> e+e- pi0 pi0 has been analyzed using 97 pb-1 of data taken with the Crystal Bal...
Using the Crystal Ball detector at the DORIS II $e^+e^−$ storage ring, we measure the $ηπ^0π^0$ mass...
Using the Crystal Ball detector at the DORIS II $e^+e^−$ storage ring, we measure the $ηπ^0π^0$ mass...
We report a measurement of the differential cross section of π0 pair production in single-tag two-ph...
We report a measurement of the differential cross section of $\pi^0$ pair production in single-tag t...
The reactione+e- →e+e- ηπ0π0→e+e- 6γ has been analysed using the full data sample taken with the Cry...
The reactione+e- →e+e- ηπ0π0→e+e- 6γ has been analysed using the full data sample taken with the Cry...
Two-photon production of the exclusive final states $p\bar p+n\pi$ (n=0, 1, 2, and 3) has been inves...
We report a measurement of the differential cross section of pi(0) pair production in single-tag two...
We report a measurement of the differential cross section of pi(0) pair production in single-tag two...
Using the Crystal Ball detector at the DORIS II e+e- storage ring, we measure the \u3b7\u3c0 0\u3c0 ...
The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ...
The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ...
The reaction $e^+e^−→e^+e^−π^0π^0$ has been analyzed using 97pb$^{−1}$ of data taken with the Crysta...
The reaction e+e- -> e+e- pi0 pi0 has been analyzed using 97 pb-1 of data taken with the Crystal Bal...
The reaction e+e- -> e+e- pi0 pi0 has been analyzed using 97 pb-1 of data taken with the Crystal Bal...
Using the Crystal Ball detector at the DORIS II $e^+e^−$ storage ring, we measure the $ηπ^0π^0$ mass...
Using the Crystal Ball detector at the DORIS II $e^+e^−$ storage ring, we measure the $ηπ^0π^0$ mass...
We report a measurement of the differential cross section of π0 pair production in single-tag two-ph...
We report a measurement of the differential cross section of $\pi^0$ pair production in single-tag t...
The reactione+e- →e+e- ηπ0π0→e+e- 6γ has been analysed using the full data sample taken with the Cry...
The reactione+e- →e+e- ηπ0π0→e+e- 6γ has been analysed using the full data sample taken with the Cry...
Two-photon production of the exclusive final states $p\bar p+n\pi$ (n=0, 1, 2, and 3) has been inves...
We report a measurement of the differential cross section of pi(0) pair production in single-tag two...
We report a measurement of the differential cross section of pi(0) pair production in single-tag two...
Using the Crystal Ball detector at the DORIS II e+e- storage ring, we measure the \u3b7\u3c0 0\u3c0 ...
The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ...
The Crystal Ball detector has been used at the DORIS II storage ring at DESY to study the reactionγγ...