Evidence is reported for a narrow structure near the $J/\psi \varphi$ threshold in exclusive $B^{+}\to J/\psi \varphi K^{+}$ decays produced in $\overline{p}p$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$. A signal of $14\pm 5$ events, with statistical significance in excess of 3.8 standard deviations, is observed in a data sample corresponding to an integrated luminosity of $2.7{\mathrm{fb}}^{-1}$, collected by the CDF II detector. The mass and natural width of the structure are measured to be $4143.0\pm 2.9(\mathrm{stat})\pm 1.2(\mathrm{syst})\mathrm{MeV}/c^2$ and ${11.7}_{-5.0}^{+8.3}(\mathrm{stat})\pm 3.7(\mathrm{syst})\mathrm{MeV}/c^2$.

The European Physical Journal C—Particles and Fields—publishes scientific manuscripts of relevance to the scientific community following careful and strict peer reviewing and, whenever appropriate and necessary, through discussion with the authors, so as to optimise scientific content and style of presentation prior to publication. In some cases significant disagreement between authors and referees (and/or editors) of the journal cannot be resolved despite all efforts and best of intentions. While the journal—notwithstanding any appeals—retains the right to reject such manuscripts, the editors of this journal may decide, in cases deemed of exceptional interest and potential significance for the field, to accept the manuscript for publication, to amend it by “comments” of the editor(s) in charge and, if appropriate, by a “reply” of the authors of the commented manuscript. The present comment is on “Study of multi-muon events produced in \(p\bar{p}\) interactions at \(\sqrt{s}=1.96\) TeV” by T. Aaltonen et al. (the CDF Collaboration, Eur. Phys. J. C, 2010 , doi: 10.1140/epjc/s10052-010-1336-0 ).

We present a search for new particles which produce narrow two-jet (dijet) resonances using proton-antiproton collision data corresponding to an integrated luminosity of $1.13{\mathrm{fb}}^{-1}$ collected with the CDF II detector. The measured dijet mass spectrum is found to be consistent with next-to-leading-order perturbative QCD predictions, and no significant evidence of new particles is found. We set upper limits at the 95% confidence level on cross sections times the branching fraction for the production of new particles decaying into dijets with both jets having a rapidity magnitude $|y|<1$. These limits are used to determine the mass exclusions for the excited quark, axigluon, flavor-universal coloron, $E_6$ diquark, color-octet techni-$\rho$, $W^{\prime }$, and $Z^{\prime }$.

The anisotropy of the azimuthal distributions of charged particles produced in $\sqrt{s_{NN}}=2.76$ TeV PbPb collisions is studied with the CMS experiment at the LHC. The elliptic anisotropy parameter, $v_2$, defined as the second coefficient in a Fourier expansion of the particle invariant yields, is extracted using the event-plane method, two- and four-particle cumulants, and Lee-Yang zeros. The anisotropy is presented as a function of transverse momentum ($p_{\mathrm{T}}$), pseudorapidity ($\eta$) over a broad kinematic range, $0.3<p_{\mathrm{T}}<20$ GeV/c, $\left|\eta \right|<2.4$, and in 12 classes of collision centrality from 0 to $80\%$. The results are compared to those obtained at lower center-of-mass energies, and various scaling behaviors are examined. When scaled by the geometric eccentricity of the collision zone, the elliptic anisotropy is found to obey a universal scaling with the transverse particle density for different collision systems and center-of-mass energies.

Measurements of inclusive charged-hadron transverse-momentum and pseudorapidity distributions are presented for proton-proton collisions at \(\sqrt{s} = 0.9 \) and 2.36 TeV. The data were collected with the CMS detector during the LHC commissioning in December 2009. For non-single-diffractive interactions, the average charged-hadron transverse momentum is measured to be 0.46 ± 0.01 (stat.) ± 0.01 (syst.) GeV/c at 0.9 TeV and 0.50 ± 0.01 (stat.) ± 0.01 (syst.) GeV/c at 2.36 TeV, for pseudorapidities between --2.4 and +2.4. At these energies, the measured pseudorapidity densities in the central region, dN _ch/dη|_|η|<0.5, are 3:48 ± 0:02 (stat.) ± 0.13 (syst.) and 4:47 ± 0:04 (stat.) ± 0.16 (syst.), respectively. The results at 0.9 TeV are in agreement with previous measurements and confirm the expectation of near equal hadron production in \( \overline p p \) and pp collisions. The results at 2.36 TeV represent the highest-energy measurements at a particle collider to date.

We report the observation of $B_s^0\mathrm{\text{−}}{\overline{B}}_s^0$ oscillations from a time-dependent measurement of the $B_s^0\mathrm{\text{−}}{\overline{B}}_s^0$ oscillation frequency $\Delta m_s$. Using a data sample of $1{\mathrm{fb}}^{-1}$ of $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ collected with the CDF II detector at the Fermilab Tevatron, we find signals of 5600 fully reconstructed hadronic $B_s$ decays, 3100 partially reconstructed hadronic $B_s$ decays, and 61 500 partially reconstructed semileptonic $B_s$ decays. We measure the probability as a function of proper decay time that the $B_s$ decays with the same, or opposite, flavor as the flavor at production, and we find a signal for $B_s^0\mathrm{\text{−}}{\overline{B}}_s^0$ oscillations. The probability that random fluctuations could produce a comparable signal is $8\times {10}^{-8}$, which exceeds $5\sigma$ significance. We measure $\Delta m_s=17.77\pm 0.10(\mathrm{stat})\pm 0.07(\mathrm{syst}){\mathrm{ps}}^{-1}$ and extract $|V_{\mathrm{td}}/V_{\mathrm{ts}}|=0.2060\pm 0.0007(\Delta m_s{)}_{-0.0060}^{+0.0081}(\Delta m_d+\mathrm{theor})$.