Branching Fraction Measurements of the Rare Bs0→ϕμ+μ−B^0_s\rightarrow\phi\mu^+\mu^- and Bs0→f2′(1525)μ+μ−B^0_s\rightarrow f_2^\prime(1525)\mu^+\mu^- Decays

The branching fraction of the rare $B^0_s\rightarrow\phi\mu^+\mu^-$ decay is measured using data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6 fb$^{-1}$, respectively. The branching fraction is reported in intervals of q$^2$, the square of the dimuon invariant mass. In the q$^2$ region between 1.1 and 6.0 GeV$^2$/c$^4$, the measurement is found to lie 3.6 standard deviations below a standard model prediction based on a combination of light cone sum rule and lattice QCD calculations. In addition, the first observation of the rare $B^0_s\rightarrow f_2^\prime(1525)\mu^+\mu^-$ decay is reported with a statistical significance of 9 standard deviations and its branching fraction is determined

Branching Fraction Measurements of the Rare Bs0→ϕμ+μ−B^0_s\rightarrow\phi\mu^+\mu^- and Bs0→f2′(1525)μ+μ−B^0_s\rightarrow f_2^\prime(1525)\mu^+\mu^-- Decays

International audienceThe branching fraction of the rare Bs0→ϕμ+μ- decay is measured using data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6  fb-1, respectively. The branching fraction is reported in intervals of q2, the square of the dimuon invariant mass. In the q2 region between 1.1 and 6.0  GeV2/c4, the measurement is found to lie 3.6 standard deviations below a standard model prediction based on a combination of light cone sum rule and lattice QCD calculations. In addition, the first observation of the rare Bs0→f2′(1525)μ+μ- decay is reported with a statistical significance of 9 standard deviations and its branching fraction is determined

Observation of the suppressed Λb0→DpK- decay with D→K+π- and measurement of its CP asymmetry

International audienceA study of Λb0 baryon decays to the DpK- final state is presented based on a proton-proton collision data sample corresponding to an integrated luminosity of 9  fb-1 collected with the LHCb detector. Two Λb0 decays are considered, Λb0→DpK- with D→K-π+ and D→K+π-, where D represents a superposition of D0 and D¯0 states. The latter process is expected to be suppressed relative to the former, and is observed for the first time. The ratio of branching fractions of the two decays is measured, and the CP asymmetry of the suppressed mode, which is sensitive to the Cabibbo-Kobayashi-Maskawa angle γ, is also reported

Observation of New Resonances Decaying to J/ψK+J/\psi K^++ and J/ψϕJ/\psi \phi

International audienceThe first observation of exotic states with a new quark content cc¯us¯ decaying to the J/ψK+ final state is reported with high significance from an amplitude analysis of the B+→J/ψϕK+ decay. The analysis is carried out using proton-proton collision data corresponding to a total integrated luminosity of 9  fb-1 collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. The most significant state, Zcs(4000)+, has a mass of 4003±6-14+4  MeV, a width of 131±15±26  MeV, and spin parity JP=1+, where the quoted uncertainties are statistical and systematic, respectively. A new 1+  X(4685) state decaying to the J/ψϕ final state is also observed with high significance. In addition, the four previously reported J/ψϕ states are confirmed and two more exotic states, Zcs(4220)+ and X(4630), are observed with significance exceeding 5 standard deviations

Simultaneous determination of CKM angle γ\gamma and charm mixing parameters

A combination of measurements sensitive to the CP violation angle γ of the Cabibbo-Kobayashi-Maskawa unitarity triangle and to the charm mixing parameters that describe oscillations between D$^{0}$ and $\overline{D} ^{0}$ mesons is performed. Results from the charm and beauty sectors, based on data collected with the LHCb detector at CERN’s Large Hadron Collider, are combined for the first time. This method provides an improvement on the precision of the charm mixing parameter y by a factor of two with respect to the current world average. The charm mixing parameters are determined to be $x=\left({0.400}_{-0.053}^{+0.052}\right)\%$ and y = $\left({0.630}_{-0.030}^{+0.033}\right)\%$. The angle γ is found to be γ = $\left({65.4}_{-4.2}^{+3.8}\right){}^{\circ}$ and is the most precise determination from a single experiment.[graphic not available: see fulltext

Search for the doubly heavy baryons Ωbc0\Omega^0_{bc} and Ξbc0\Xi^0_{bc} decaying to Λc+π−\Lambda^+_c \pi^- and Ξc+π−\Xi^+_c \pi^-

The first search for the doubly heavy baryon and a search for the baryon are performed using collision data collected via the experiment from 2016 to 2018 at a centre-of-mass energy of , corresponding to an integrated luminosity of 5.2 . The baryons are reconstructed via their decays to and . No significant excess is found for invariant masses between 6700 and 7300 , in a rapidity range from 2.0 to 4.5 and a transverse momentum range from 2 to 20 . Upper limits are set on the ratio of the and production cross-section times the branching fraction to ( ) relative to that of the ( ) baryon, for different lifetime hypotheses, at 95% confidence level. The upper limits range from to for the ( ) decay, and from to for the ( ) decay, depending on the considered mass and lifetime of the ( ) baryon

Precise measurement of the fs/fdf_s/f_d ratio of fragmentation fractions and of Bs0B^0_s decay branching fractions

International audienceThe ratio of the Bs0 and B0 fragmentation fractions, fs/fd, in proton-proton collisions at the LHC, is obtained as a function of B-meson transverse momentum and collision center-of-mass energy from the combined analysis of different B-decay channels measured by the LHCb experiment. The results are described by a linear function of the meson transverse momentum or with a function inspired by Tsallis statistics. Precise measurements of the branching fractions of the Bs0→J/ψϕ and Bs0→Ds-π+ decays are performed, reducing their uncertainty by about a factor of 2 with respect to previous world averages. Numerous Bs0 decay branching fractions, measured at the LHCb experiment, are also updated using the new values of fs/fd and branching fractions of normalization channels. These results reduce a major source of systematic uncertainty in several searches for new physics performed through measurements of Bs0 branching fractions

Precise measurement of the fs/fdf_s/f_d ratio of fragmentation fractions and of Bs0B^0_s decay branching fractions

The ratio of the $B^0_s$ and $B^0$ fragmentation fractions, $f_s/f_d$, in proton-proton collisions at the LHC, is obtained as a function of B-meson transverse momentum and collision center-of-mass energy from the combined analysis of different B-decay channels measured by the LHCb experiment. The results are described by a linear function of the meson transverse momentum or with a function inspired by Tsallis statistics. Precise measurements of the branching fractions of the $B_s$ $^0 → J/ψϕ$ and $B_s^0 → D-_s π^+$ decays are performed, reducing their uncertainty by about a factor of 2 with respect to previous world averages. Numerous $B_s^0$ decay branching fractions, measured at the LHCb experiment, are also updated using the new values of $f_s/f_d$ and branching fractions of normalization channels. These results reduce a major source of systematic uncertainty in several searches for new physics performed through measurements of $B_s^0$ branching fractions