Inhaltszusammenfassung

We have performed the first measurement of the coherent ψ(2S)ψ(2S) photo-production cross section in ultra-peripheral Pb--Pb collisions at the LHC. This charmonium excited state is reconstructed via the ψ(2S)→l+l−ψ(2S)→l+l− and ψ(2S)→J/ψπ+π−ψ(2S)→J/ψπ+π− decays, where the J/ψJ/ψ decays into two leptons. The analysis is based on an event sample corresponding to an integrated luminosity of about 22 μb−122 μb−1. The cross section for coherent ψ(2S)ψ(2S) production in the rapidity interval −0.9<y...We have performed the first measurement of the coherent ψ(2S)ψ(2S) photo-production cross section in ultra-peripheral Pb--Pb collisions at the LHC. This charmonium excited state is reconstructed via the ψ(2S)→l+l−ψ(2S)→l+l− and ψ(2S)→J/ψπ+π−ψ(2S)→J/ψπ+π− decays, where the J/ψJ/ψ decays into two leptons. The analysis is based on an event sample corresponding to an integrated luminosity of about 22 μb−122 μb−1. The cross section for coherent ψ(2S)ψ(2S) production in the rapidity interval −0.9<y<0.9−0.9<y<0.9 is View the MathML sourcedσψ(2S)coh/dy=0.83±0.19(stat+syst) mb. The ψ(2S)ψ(2S) to J/ψJ/ψ coherent cross section ratio is View the MathML source0.34−0.07+0.08(stat+syst). The obtained results are compared to predictions from theoretical models.» weiterlesen» einklappen

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DDC Sachgruppe:
Physik