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The study of $\gamma\gamma\to\gamma\psi(2S)$ at Belle
- Source :
- Physical review / D 105(11), 112011 (2022). doi:10.1103/PhysRevD.105.112011
- Publication Year :
- 2022
- Publisher :
- Deutsches Elektronen-Synchrotron, DESY, Hamburg, 2022.
-
Abstract
- Physical review / D 105(11), 112011 (2022). doi:10.1103/PhysRevD.105.112011<br />Using $980~\rm fb^{-1}$ of data on and around the $\Upsilon(nS)(n=1,2,3,4,5)$ resonances collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider, the two-photon process $\gamma\gamma\to \gamma\psi(2S)$ is studied from $\sqrt{s} = 3.7$ to $4.2~{\rm GeV}$ for the first time. Evidence is found for a structure in the invariant mass distribution of $\gamma\psi(2S)$ at $M_1 = 3921.3\pm 2.4 \pm 1.6~{\rm MeV}/c^2$ with a width of $\Gamma_1 = 0.0\pm 5.3 \pm 2.0~{\rm MeV}$ and a significance of $4.0\sigma$ including systematic uncertainties, and another structure is seen at $M_2 = 4014.4\pm 4.1 \pm 0.5~{\rm MeV}/c^2$ with a width of $\Gamma_2 = 6\pm 16 \pm 6~{\rm MeV}$ and a global significance of $2.8\sigma$ including the look-elsewhere effect, if the mass spectrum is parametrized with the incoherent sum of two Breit-Wigner functions. The upper limits of the widths are determined to be $\Gamma_1^{\rm UL} = 11.5~{\rm MeV}$ and $\Gamma_2^{\rm UL} = 39.3~{\rm MeV}$ at 90% confidence level. The production rates are determined to be $\Gamma_{\gamma\gamma}{\cal B}(R_1\to\gamma\psi(2S)) = 8.2\pm 2.3\pm 0.9~{\rm eV}$ assuming $(J^{PC}, |\lambda|) =(0^{++}, 0)$ and $1.6\pm 0.5\pm 0.2~{\rm eV}$ with $(2^{++}, 2)$ for the first structure and $\Gamma_{\gamma\gamma}{\cal B}(R_2\to\gamma\psi(2S)) = 5.3\pm 2.7\pm 2.5~{\rm eV}$ with $(0^{++}, 0)$ and $1.1\pm 0.5\pm 0.5~{\rm eV}$ with $(2^{++}, 2)$ for the second one. Here, the first errors are statistical and the second systematic.<br />Published by Inst., Melville, NY
- Subjects :
- two-photon [exchange]
data analysis method
BELLE
annihilation [electron positron]
electron positron: annihilation
High Energy Physics - Experiment
width [mass]
mass: width
KEK-B
width: upper limit
[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]
ddc:530
structure
mass spectrum: (photon psi(3685))
branching ratio [width]
psi(3685)
upper limit [width]
exchange: two-photon
3.7-4.2 GeV-cms
(photon psi(3685)) [mass spectrum]
width: branching ratio
statistical [error]
electron positron: colliding beams
Breit-Wigner
error: statistical
photon photon --> photon psi(3685)
colliding beams [electron positron]
experimental results
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- Physical review / D 105(11), 112011 (2022). doi:10.1103/PhysRevD.105.112011
- Accession number :
- edsair.doi.dedup.....bf4f553119849b4f015ca64d5e367003
- Full Text :
- https://doi.org/10.3204/pubdb-2022-06613