Erratum to: Comparison of the Z/γ* + jets to γ + jets cross sections in pp collisions at √s = 8

Erratum to: JHEP10(2015)128. ArXiv ePrint: 1505.06520. The online version of the original article can be found at http://dx.doi.org/10.1007/JHEP10(2015)128

Violenza e diritto nell'era nucleare

A search has been performed for long-lived particles that could have come to rest within the CMS detector, using the time intervals between LHC beam crossings. The existence of such particles could be deduced from observation of their decays via energy deposits in the CMS calorimeter appearing at times that are well separated from any proton–proton collisions. Using a data set corresponding to an integrated luminosity of 18.6fb-1 of 8TeV proton–proton collisions, and a search interval corresponding to 281 h of trigger livetime, 10 events are observed, with a background prediction of 13.2+3.6−2.5 events. Limits are presented at 95 % confidence level on gluino and top squark production, for over 13 orders of magnitude in the mean proper lifetime of the stopped particle. Assuming a cloud model of R-hadron interactions, a gluino with mass ≲1000GeV and a top squark with mass ≲525GeV are excluded, for lifetimes between 1 μs and 1000s. These results are the most stringent constraints on stopped particles to date

Suppression of non-prompt J/psi, prompt J/psi, and Upsilon(1S) in PbPb collisions at root s(NN)=2.76 TeV

Yields of prompt and non-prompt J/ψ, as well as Y(1S) mesons, are measured by the CMS experiment via their μ +μ - decays in PbPb and pp collisions at √/s NN = 2.76 TeV for quarkonium rapidity |y| < 2.4. Differential cross sections and nuclear modification factors are reported as functions of y and transverse momentum pT, as well as collision centrality. For prompt J/ψ with relatively high pT (6.5 < pT < 30 GeV/c), a strong, centrality-dependent suppression is observed in PbPb collisions, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. In the same kinematic range, a suppression of non-prompt J/ψ, which is sensitive to the in-medium b-quark energy loss, is measured for the first time. Also the low-pT Y(1S) mesons are suppressed in PbPb collisions. © CERN

Party government : a rationalistic conception

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