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تسجيل مستخدم جديدMeasurement of the $Upsilon$ polarizations in $pp$ collisions at $sqrt{s}$=7 and 8TeV
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The polarization of the $Upsilon(1S)$, $Upsilon(2S)$ and $Upsilon(3S) $mesons, produced in $pp$ collisions at centre-of-mass energies $sqrt{s}$=7 and 8TeV, is measured using data samples collected by the LHCb experiment, corresponding to integrated luminosities of 1 and 2fb$^{-1}$, respectively. The measurements are performed in three polarization frames, using $Upsilontomu^+mu^-$ decays in the kinematic region of the transverse momentum $p_{T}(Upsilon)<30GeV/c$, and rapidity $2.2<y(Upsilon)<4.5$. No large polarization is observed.
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The production of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons in proton-proton collisions at the centre-of-mass energy of sqrt(s)=7 TeV is studied with the LHCb detector. The analysis is based on a data sample of 25 pb-1 collected at the Large Ha
dron Collider. The Upsilon mesons are reconstructed in the decay mode Upsilon -> mu+ mu- and the signal yields are extracted from a fit to the mu+ mu- invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the Upsilon transverse momentum pT and rapidity y, over the range pT < 15 GeV/c and 2.0 < y < 4.5. The cross-sections times branching fractions, integrated over these kinematic ranges, are measured to be sigma(pp -> Upsilon(1S) X) x B(Upsilon(1S)->mu+ mu-) = 2.29 {pm} 0.01 {pm} 0.10 -0.37 +0.19 nb, sigma(pp -> Upsilon(2S) X) x B(Upsilon(2S)->mu+ mu-) = 0.562 {pm} 0.007 {pm} 0.023 -0.092 +0.048 nb, sigma(pp -> Upsilon(3S) X) x B(Upsilon(3S)->mu+ mu-) = 0.283 {pm} 0.005 {pm} 0.012 -0.048 +0.025 nb, where the first uncertainty is statistical, the second systematic and the third is due to the unknown polarisation of the three Upsilon states.
The polarizations of prompt J/psi and psi(2S) mesons are measured in proton-proton collisions at sqrt(s) = 7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 inverse femtobar
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The production of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb^{-1} collected in proton-proton collision
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The production cross-sections of $Upsilon(1S)$, $Upsilon(2S)$ and $Upsilon(3S)$ mesons in proton-proton collisions at $sqrt{s}$= 13 TeV are measured with a data sample corresponding to an integrated luminosity of $277 pm 11$ $rm pb^{-1}$ recorded by
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