Measurement of the cross section for direct-photon production in association with a heavy quark in pp¯ collisions at s√ = 1.96 TeV

We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of s√=1.96  TeV proton-antiproton collisions corresponding to 9.1  fb−1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering a photon transverse momentum between 30 and 300 GeV, photon rapidities |yγ|20  GeV, and jet rapidities |yjet|<1.5. The results are compared with several theoretical predictions

Indirect measurement of sin⁡2θW\sin^2 \theta_W (or MWM_W) using μ+μ−\mu^+\mu^- pairs from γ∗/Z\gamma^*/Z bosons produced in ppˉp\bar{p} collisions at a center-of-momentum energy of 1.96 TeV

Drell-Yan lepton pairs are produced in the process $p\bar{p} \rightarrow \mu^+\mu^- + X$ through an intermediate $\gamma^*/Z$ boson. The forward-backward asymmetry in the polar-angle distribution of the $\mu^-$ as a function of the invariant mass of the $\mu^+\mu^-$ pair is used to obtain the effective leptonic determination $\sin^2 \theta^{lept}_{eff}$ of the electroweak-mixing parameter $\sin^2 \theta_W$, from which the value of $\sin^2 \theta_W$ is derived assuming the standard model. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.2 fb-1 of integrated luminosity from $p\bar{p}$ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of $\sin^2 \theta^{lept}_{eff}$ is found to be 0.2315 +- 0.0010, where statistical and systematic uncertainties are combined in quadrature. When interpreted within the context of the standard model using the on-shell renormalization scheme, where $\sin^2 \theta_W = 1 - M_W^2/M_Z^2$, the measurement yields $\sin^2 \theta_W$ = 0.2233 +- 0.0009, or equivalently a W-boson mass of 80.365 +- 0.047 GeV/c^2. The value of the W-boson mass is in agreement with previous determinations in electron-positron collisions and at the Tevatron collider

Measurement of the CP-violating weak phase ϕsϕ_s and the decay width difference ΔΓsΔΓ_s using the Bs0→J/ψϕ(1020)B^{0}_{s}→J/ψϕ(1020) decay channel in pp collisions at s=8\sqrt{s} = 8 TeV

The CP-violating weak phase $ϕ_s$ of the $B^{0}_{s}$ meson and the decay width difference $ΔΓ_s$ of the Bs0 light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of $B^{0}_{s}→J/ψϕ(1020)→μ^{+}μ^{−}K^{+}K^{−}$ decays. The analysed data set corresponds to an integrated luminosity of 19.7fb$^{−1}$ collected in pp collisions at a centre-of-mass energy of 8TeV . A total of 49 200 reconstructed $B^{0}_{s}$ decays are used to extract the values of $ϕ_s$ and $ΔΓ_s$ by performing a time-dependent and flavour-tagged angular analysis of the $μ^{+}μ^{−}K^{+}K^{−}$ final state. The weak phase is measured to be $ϕ_s$=−0.075±0.097(stat)±0.031(syst) rad , and the decay width difference is $ΔΓ_s$=0.095±0.013(stat)±0.007(syst) ps$^{−1}$

Search for lepton flavour violating decays of the Higgs boson to eττ and eμ in proton–proton collisions at s\sqrt{s} = 8 TeV

A direct search for lepton flavour violating decays of the Higgs boson (H) in the H→eτ and H→eμ channels is described. The data sample used in the search was collected in proton–proton collisions at $\sqrt{s}$=8 TeV with the CMS detector at the LHC and corresponds to an integrated luminosity of 19.7 fb$^{−1}$. No evidence is found for lepton flavour violating decays in either final state. Upper limits on the branching fractions, B(H→eτ)<0.69% and B(H→eμ)<0.035% , are set at the 95% confidence level. The constraint set on B(H→eτ) is an order of magnitude more stringent than the existing indirect limits. The limits are used to constrain the corresponding flavour violating Yukawa couplings, absent in the standard model

Forward-backward asymmetry of Drell–Yan lepton pairs in pp collisions at s\sqrt{s} = 8 TeV

A measurement of the forward-backward asymmetry AFB of oppositely charged lepton pairs (μμ and ee) produced via Z/γ∗ boson exchange in pp collisions at $\sqrt{s}$ = 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.7 fb$^{−1}$ collected with the CMS detector at the LHC. The measurement of $A_{FB}$ is performed for dilepton masses between 40 GeV and 2 TeV and for dilepton rapidity up to 5. The $A_{FB}$ measurements as a function of dilepton mass and rapidity are compared with the standard model predictions

Measurements of tt‾t\overline{t} spin correlations and top quark polarization using dilepton final states in pp collisions at s\sqrt{s} = 8 TeV

Measurements of the top quark-antiquark ($t\overline{t}$) spin correlations and the top quark polarization are presented for $t\overline{t}$ pairs produced in pp collisions at $\sqrt{s}$=8  TeV. The data correspond to an integrated luminosity of 19.5  fb$^{−1}$ collected with the CMS detector at the LHC. The measurements are performed using events with two oppositely charged leptons (electrons or muons) and two or more jets, where at least one of the jets is identified as originating from a bottom quark. The spin correlations and polarization are measured from the angular distributions of the two selected leptons, both inclusively and differentially, with respect to the invariant mass, rapidity, and transverse momentum of the $t\overline{t}$ system. The measurements are unfolded to the parton level and found to be in agreement with predictions of the standard model. A search for new physics in the form of anomalous top quark chromo moments is performed. No evidence of new physics is observed, and exclusion limits on the real part of the chromo-magnetic dipole moment and the imaginary part of the chromo-electric dipole moment are evaluated

Measurement of prompt ψ\psi(2S) to J/ψ\psi yield ratios in Pb-Pb and p-p collisions at sNN\sqrt {sNN} = 2.76 TeV

The ratio between the prompt ψ(2S) and J/ψ yields, reconstructed via their decays into μ+μ-, is measured in Pb-Pb and p-p collisions at sNN=2.76  TeV. The analysis is based on Pb-Pb and p-p data samples collected by CMS at the Large Hadron Collider, corresponding to integrated luminosities of 150  μb-1 and 5.4  pb-1, respectively. The double ratio of measured yields (Nψ(2S)/NJ/ψ)Pb-Pb/(Nψ(2S)/NJ/ψ)p-p is computed in three Pb-Pb collision centrality bins and two kinematic ranges: one at midrapidity, |y|<1.6, covering the transverse momentum range 6.5<pT<30  GeV/c, and the other at forward rapidity, 1.6<|y|<2.4, extending to lower pT values, 3<pT<30  GeV/c. The centrality-integrated double ratio changes from 0.45±0.13(stat)±0.07(syst) in the first range to 1.67±0.34(stat)±0.27(syst) in the second. This difference is most pronounced in the most central collisions

Spatial-temporal correlations in the process to self-organized criticality

A new type of spatial-temporal correlation in the process approaching to the self-organized criticality is investigated for the two simple models for biological evolution. The change behaviors of the position with minimum barrier are shown to be quantitatively different in the two models. Different results of the correlation are given for the two models. We argue that the correlation can be used, together with the power-law distributions, as criteria for self-organized criticality.Comment: 3 pages in RevTeX, 3 eps figure