Measurement of prompt Jψ\psi pair production in pp collisions at \sqrt s = 7 Tev

Production of prompt J/ ψ meson pairs in proton-proton collisions at s s√ = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb −1 . The two J/ ψ mesons are fully reconstructed via their decays into μ + μ − pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ ψ pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/ ψ transverse momentum ( p T J/ ψ ) and rapidity (| y J/ ψ |): | y J/ ψ | 6.5 GeV/ c ; 1.2 4.5 GeV/ c . The total cross section, assuming unpolarized prompt J/ ψ pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ ψ polarization imply modifications to the cross section ranging from −31% to +27%

Measurements of the t(t)Overbar charge asymmetry using the dilepton decay channel in pp collisions at root s=7 TeV

The tt¯ charge asymmetry in proton-proton collisions at s√ = 7 TeV is measured using the dilepton decay channel (ee, e μ , or μμ ). The data correspond to a total integrated luminosity of 5.0 fb −1 , collected by the CMS experiment at the LHC. The tt and lepton charge asymmetries, defined as the differences in absolute values of the rapidities between the reconstructed top quarks and antiquarks and of the pseudorapidities between the positive and negative leptons, respectively, are measured to be A C = −0 . 010 ± 0 . 017 (stat . ) ± 0 . 008 (syst . ) and AlepC = 0 . 009 ± 0 . 010 (stat . ) ± 0 . 006 (syst . ). The lepton charge asymmetry is also measured as a function of the invariant mass, rapidity, and transverse momentum of the tt¯ system. All measurements are consistent with the expectations of the standard model

Block driving chain (gall's chain) of the increased load capability

В статті розглядається нова конструкція ланки ланцюга, що відрізняється від попередніх новим виконанням бічних пластин з відбортовкою отворів. Запропонована конструкція забезпечує підвищення навантажувальної здатності ланцюга і довговічності роботи у важких умовах експлуатації, а також зниження матеріаломісткості виготовлення ланцюга.The article "Block Driving Chain (Gall's Chain) of the increased Load Capability" by A.Bondarenko and M.Mikhailov deals with a new design of the chain link that differs essentially from the previosly used by employing lateral plates having drawn down holes along the contour. The suggested design provides the increase for the load capability of the chain and durability of its operation under rigorous service as well as the reduction of the material consumption in the process of chain manufacturing

On the mechanism of cross slip in Ni \u3c inf\u3e 3 AI

The mechanical properties of Ll2 intermetallic alloys have been previously described by models based on the assumption that cube cross slip is the rate-limiting step. In this study, it was demonstrated that the cube cross-slip event must be reversible under a change in loading direction. This observation allows the cross-slip models to remain consistent with cyclic deformation data. Additionally, this observation was used as a critical test of the available cross-slip models. It was demonstrated that the rate-limiting step cannot be a total cross-slip event, in which both α/2(110) superpartial dislocations cross slip to the cube plane. Conversely, the limited cross-slip event proposed by Paidar, Pope, and Vitek (PPV) was demonstrated to be consistent with the reversibility constraint. This lends additional experimental support to the PPV model. © 1989 The Metallurgical Society of AIME