Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

Test of lepton universality in b→sℓ+ℓ−b \rightarrow s \ell^+ \ell^- decays

The first simultaneous test of muon-electron universality using $B^{+}\rightarrow K^{+}\ell^{+}\ell^{-}$ and $B^{0}\rightarrow K^{*0}\ell^{+}\ell^{-}$ decays is performed, in two ranges of the dilepton invariant-mass squared, $q^{2}$. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 $\mathrm{fb}^{-1}$. Each of the four lepton universality measurements reported is either the first in the given $q^{2}$ interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-046.html (LHCb public pages

Precision measurement of CP\it{CP} violation in the penguin-mediated decay Bs0→ϕϕB_s^{0}\rightarrow\phi\phi

A flavor-tagged time-dependent angular analysis of the decay $B_s^{0}\rightarrow\phi\phi$ is performed using $pp$ collision data collected by the LHCb experiment at % at $\sqrt{s}=13$ TeV, the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The $\it{CP}$-violating phase and direct $\it{CP}$-violation parameter are measured to be $\phi_{s\bar{s}s} = -0.042 \pm 0.075 \pm 0.009$ rad and $|\lambda|=1.004\pm 0.030 \pm 0.009$, respectively, assuming the same values for all polarization states of the $\phi\phi$ system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using $pp$ collisions at center-of-mass energies of 7 and 8 TeV, yielding $\phi_{s\bar{s}s} = -0.074 \pm 0.069$ rad and $|lambda|=1.009 \pm 0.030$. This is the most precise study of time-dependent $\it{CP}$ violation in a penguin-dominated $B$ meson decay. The results are consistent with $\it{CP}$ symmetry and with the Standard Model predictions.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-001.html (LHCb public pages

Observation of a resonant structure near the Ds+Ds−D_s^+ D_s^- threshold in the B+→Ds+Ds−K+B^+\to D_s^+ D_s^- K^+ decay

An amplitude analysis of the $B^+\to D_s^+ D_s^- K^+$ decay is carried out to study for the first time its intermediate resonant contributions, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. A near-threshold peaking structure, referred to as $X(3960)$, is observed in the $D_s^+ D_s^-$ invariant-mass spectrum with significance greater than 12 standard deviations. The mass, width and the quantum numbers of the structure are measured to be $3956\pm5\pm10$ MeV, $43\pm13\pm8$ MeV and $J^{PC}=0^{++}$, respectively, where the first uncertainties are statistical and the second systematic. The properties of the new structure are consistent with recent theoretical predictions for a state composed of $c\bar{c}s\bar{s}$ quarks. Evidence for an additional structure is found around 4140 MeV in the $D_s^+ D_s^-$ invariant mass, which might be caused either by a new resonance with the $0^{++}$ assignment or by a $J/\psi \phi\leftrightarrow D_s^+ D_s^-$ coupled-channel effect.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-018.html (LHCb public pages

Measurement of the Λb0→Λ(1520)μ+μ−\Lambda_{b}^{0}\to \Lambda(1520) \mu^{+}\mu^{-} differential branching fraction

The branching fraction of the rare decay $\Lambda_{b}^{0}\to \Lambda(1520) \mu^{+}\mu^{-}$ is measured for the first time, in the squared dimuon mass intervals, $q^2$, excluding the $J/\psi$ and $\psi(2S)$ regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of $9\ \mathrm{fb}^{-1}$. The result in the highest$q^{2}$interval,$q^{2} >15.0\ \mathrm{GeV}^2/c^4$, where theoretical predictions have the smallest model dependence, agrees with the predictions.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-050.html (LHCb public pages

Search for triboson W±W±W∓ production in pp collisions at √s = 8 TeV with the ATLAS detector

This paper reports a search for triboson W±W±W∓ production in two decay channels (W±W±W∓ → ±ν±ν∓ν and W±W±W∓ → ±ν±ν j j with = e, μ) in proton-proton collision data corresponding to an integrated luminosity of 20.3 fb−1 at a centreof-mass energy of 8 TeV with the ATLAS detector at the Large Hadron Collider. Events with exactly three charged leptons, or two leptons with the same electric charge in association with two jets, are selected. The total number of events observed in data is consistent with the Standard Model (SM) predictions. The observed 95% confidence level upper limit on the SM W±W±W∓ production cross section is found to be 730 fb with an expected limit of 560 fb in the absence of SM W±W±W∓ production. Limits are also set on WWWW anomalous quartic gauge couplings

Search for rare decays of D0 mesons into two muons

A search for the very rare D 0 → μ + μ − decay is performed using data collected by the LHCb experiment in proton-proton collisions at √ s = 7 , 8, and 13 TeV, corresponding to an integrated luminosity of 9     fb − 1 . The search is optimized for D 0 mesons from D * + → D 0 π + decays but is also sensitive to D 0 mesons from other sources. No evidence for an excess of events over the expected background is observed. An upper limit on the branching fraction of this decay is set at B ( D 0 → μ + μ − ) < 3.1 × 10 − 9 at a 90% C.L. This represents the world’s most stringent limit, constraining models of physics beyond the standard model

Measurement of the ratios of branching fractions R(D*) and R(D0)

The ratios of branching fractions R ( D ∗ ) ≡ B ( ¯ B → D ∗ τ − ¯ ν τ ) / B ( ¯ B → D ∗ μ − ¯ ν μ ) and R ( D 0 ) ≡ B ( B − → D 0 τ − ¯ ν τ ) / B ( B − → D 0 μ − ¯ ν μ ) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0     fb − 1 of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ − → μ − ν τ ¯ ν μ . The measured values are R ( D ∗ ) = 0.281 ± 0.018 ± 0.024 and R ( D 0 ) = 0.441 ± 0.060 ± 0.066 , where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is ρ = − 0.43 . The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the standard model

Precision measurement of CP violation in the penguin-mediated decay Bs0→ϕϕ

A flavor-tagged time-dependent angular analysis of the decay B 0 s → ϕ ϕ is performed using p p collision data collected by the LHCb experiment at the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6     fb − 1 . The C P -violating phase and direct C P -violation parameter are measured to be ϕ s ¯ s s s = − 0.042 ± 0.075 ± 0.009     rad and | λ | = 1.004 ± 0.030 ± 0.009 , respectively, assuming the same values for all polarization states of the ϕ ϕ system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using p p collisions at center-of-mass energies of 7 and 8 TeV, yielding ϕ s ¯ s s s = − 0.074 ± 0.069     rad and | λ | = 1.009 ± 0.030 . This is the most precise study of time-dependent C P violation in a penguin-dominated B meson decay. The results are consistent with C P symmetry and with the standard model predictions

First measurement of the Z→μ+μ− angular coefficients in the forward region of pp collisions at √s = 13 TeV

The first study of the angular distribution of μ + μ − pairs produced in the forward rapidity region via the Drell-Yan reaction p p → γ ∗ / Z + X → ℓ + ℓ − + X is presented, using data collected with the LHCb detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.1     fb − 1 . The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the Z -boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton