Visualizing chemical states and defects induced magnetism of graphene oxide by spatially-resolved-X-ray microscopy and spectroscopy

[[abstract]]This investigation studies the various magnetic behaviors of graphene oxide (GO) and reduced graphene oxides (rGOs) and elucidates the relationship between the chemical states that involve defects therein and their magnetic behaviors in GO sheets. Magnetic hysteresis loop reveals that the GO is ferromagnetic whereas photo-thermal moderately reduced graphene oxide (M-rGO) and heavily reduced graphene oxide (H-rGO) gradually become paramagnetic behavior at room temperature. Scanning transmission X-ray microscopy and corresponding X-ray absorption near-edge structure spectroscopy were utilized to investigate thoroughly the variation of the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups, as well as the C 2p(σ*)-derived states in flat and wrinkle regions to clarify the relationship between the spatially-resolved chemical states and the magnetism of GO, M-rGO and H-rGO. The results of X-ray magnetic circular dichroism further support the finding that C 2p(σ*)-derived states are the main origin of the magnetism of GO. Based on experimental results and first-principles calculations, the variation in magnetic behavior from GO to M-rGO and to H-rGO is interpreted, and the origin of ferromagnetism is identified as the C 2p(σ*)- derived states that involve defects/vacancies rather than the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups on GO sheets.[[notice]]補正完

Measurement of the WZ production cross section in pp collisions at root s=13 Tev

Peer reviewe

Relative Modification of Prompt psi(2S) and J/psi Yields from pp to PbPb Collisions at root(S)(NN)=5.02 TeV

Peer reviewe

Search for physics beyond the standard model in events with two leptons of same sign, missing transverse momentum, and jets in proton-proton collisions at root s=13TeV

A data sample of events from proton–proton collisions with two isolated same-sign leptons, missing transverse momentum, and jets is studied in a search for signatures of new physics phenomena by the CMS Collaboration at the LHC. The data correspond to an integrated luminosity of 35.9 fb−1, and a center-of-mass energy of 13 TeV. The properties of the events are consistent with expectations from standard model processes, and no excess yield is observed. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos, squarks, and same-sign top quarks, as well as top-quark associated production of a heavy scalar or pseudoscalar boson decaying to top quarks, and on the standard model production of events with four top quarks. The observed lower mass limits are as high as 1500 GeV for gluinos, 830 GeV for bottom squarks. The excluded mass range for heavy (pseudo)scalar bosons is 350–360 (350–410) GeV. Additionally, model-independent limits in several topological regions are provided, allowing for further interpretations of the results

Search for resonant production of second-generation sleptons with same-sign dimuon events in proton-proton collisions at root s=13 TeV

A search is presented for resonant production of second-generation sleptons ( μ˜L , ν˜μ ) via the R-parity-violating coupling λ′211 to quarks, in events with two same-sign muons and at least two jets in the final state. The smuon (muon sneutrino) is expected to decay into a muon and a neutralino (chargino), which will then decay into a second muon and at least two jets. The analysis is based on the 2016 data set of proton-proton collisions at s√=13TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb−1 . No significant deviation is observed with respect to standard model expectations. Upper limits on cross sections, ranging from 0.24 to 730 fb , are derived in the context of two simplified models representing the dominant signal contributions leading to a same-sign muon pair. The cross section limits are translated into coupling limits for a modified constrained minimal supersymmetric model with λ′211 as the only nonzero R-parity violating coupling. The results significantly extend restrictions of the parameter space compared with previous searches for similar models

Search for supersymmetry in the multijet and missing transverse momentum final state in pp collisions at 13 TeV

Peer reviewe

Suppression and azimuthal anisotropy of prompt and nonprompt J/psi production in PbPb collisions at root S-NN=2.76 TeV

The nuclear modification factor RAA and the azimuthal anisotropy coefficient v2 of prompt and nonprompt (i.e. those from decays of b hadrons) J/ψ mesons, measured from PbPb and pp collisions at sNN−−−√=2.76 TeV at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta pT>6.5 GeV/c and rapidity |y|<2.4 , extending down to pT=3 GeV/c in the 1.6<|y|<2.4 range. The v2 of prompt J/ψ is found to be nonzero, but with no strong dependence on centrality, rapidity, or pT over the full kinematic range studied. The measured v2 of nonprompt J/ψ is consistent with zero. The RAA of prompt J/ψ exhibits a suppression that increases from peripheral to central collisions but does not vary strongly as a function of either y or pT in the fiducial range. The nonprompt J/ψ RAA shows a suppression which becomes stronger as rapidity or pT increases. The v2 and RAA of open and hidden charm, and of open charm and beauty, are compared

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

Studies of B_{s2}^{*} (5840)⁰ and B_{s1} (5830)⁰ mesons including the observation of the B_{s2}^{*} (5840)⁰ → B⁰K_{s}^{0} decay in proton-proton collisions at √s = 8 TeV

Measurements of B_{s2}^{*} (5840)⁰ and B_{s1} (5840)⁰ mesons are performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of 19.6 fb⁻¹, collected with the CMS detector at the LHC at a centre-of-mass energy of 8 TeV. The analysis studies P-wave B_{s}^{0} meson decays into B^{(*)}⁺K⁻ and B^{(*)}⁰K_{s}^{0}, where the B⁺ and B⁰ mesons are identified using the decays B⁺ → J/φK⁺ and B⁰ → J/φK* (892)⁰. The masses of the P-wave B_{s}^{0} meson states are measured and the natural width of the B_{*}^{s2} (5840)⁰ state is determined. The first measurement of the mass difference between the charged and neutral B* mesons is also presented. The B_{*}^{s2} (5840)⁰ decay to B⁰K_{s}^{0} is observed, together with a measurement of its branching fraction relative to the B_{s2}^{*} (5840)⁰ → B⁺K⁻ decay