Measurement of resonant and CP components in ¯B0s → J/ψπ+π− decays

Structure of the decay ¯ B 0 s → J / ψ π + π − is studied using data corresponding to 3   fb − 1 of integrated luminosity from p p collisions produced by the LHC and collected by the LHCb detector. Five interfering π + π − states are required to describe the decay: f 0 ( 980 ) , f 0 ( 1500 ) , f 0 ( 1790 ) , f 2 ( 1270 ) , and f ′ 2 ( 1525 ) . An alternative model including these states and a nonresonant J / ψ π + π − component also provides a good description of the data. Based on the different transversity components measured for the spin-2 intermediate states, the final state is found to be compatible with being entirely C P odd. The C P -even part is found to be < 2.3 % at a 95% confidence level. The f 0 ( 500 ) state is not observed, allowing a limit to be set on the absolute value of the mixing angle with the f 0 ( 980 ) of < 7. 7 ∘ at a 90% confidence level, consistent with a tetraquark interpretation of the f 0 ( 980 ) substructure

Study of B0(s)→K0Sh+h′− decays with first observation of B0s→K0SK±π∓ and B0s→K0Sπ+π

A search for charmless three-body decays of B 0 and B0s mesons with a K0S meson in the final state is performed using the pp collision data, corresponding to an integrated luminosity of 1.0 fb−1, collected at a centre-of-mass energy of 7 TeV recorded by the LHCb experiment. Branching fractions of the B0(s)→K0Sh+h′− decay modes (h (′) = π, K), relative to the well measured B0→K0Sπ+π− decay, are obtained. First observation of the decay modes B0s→K0SK±π∓ and B0s→K0Sπ+π− and confirmation of the decay B0→K0SK±π∓ are reported. The following relative branching fraction measurements or limits are obtained $ B(B0→K0SK±π∓)B(B0→K0Sπ+π−)=0.128±0.017(stat.)±0.009(syst.),B(B0→K0SK+K−)B(B0→K0Sπ+π−)=0.385±0.031(stat.)±0.023(syst.),B(B0s→K0Sπ+π−)B(B0→K0Sπ+π−)=0.29±0.06(stat.)±0.03(syst.)±0.02(fs/fd),B(B0s→K0SK±π∓)B(B0→K0Sπ+π−)=1.48±0.12(stat.)±0.08(syst.)±0.12(fs/fd)B(B0s→K0SK+K−)B(B0→K0Sπ+π−)∈[0.004;0.068]at90%CL

First measurement of time-dependent CP violation in B0s→K+K− decays

Direct and mixing-induced CP-violating asymmetries in B0s→K+K− decays are measured for the first time using a data sample of pp collisions, corresponding to an integrated luminosity of 1.0 fb−1, collected with the LHCb detector at a centre-of-mass energy of 7 TeV. The results are C KK  = 0.14 ± 0.11 ± 0.03 and S KK  = 0.30 ± 0.12 ± 0.04, where the first uncertainties are statistical and the second systematic. The corresponding quantities are also determined for B 0 → π + π − decays to be C ππ  = −0.38 ± 0.15 ± 0.02 and S ππ  = −0.71 ± 0.13 ± 0.02, in good agreement with existing measurements

Measurement of the differential branching fraction of the decay Λb0→Λμ+μ-

The differential branching fraction of the decay Λ0 b → Λμ+μ− is measured as a function of the square of the dimuon invariant mass, q2. A yield of 78 ± 12 Λ0 b → Λμ+μ− decays is observed using data, corresponding to an integrated luminosity of 1.0 fb−1, collected by the LHCb experiment at a centre-of-mass energy of 7 TeV. A significant signal is found in the q2 region above the square of the J /ψ mass, while at lower-q2 values upper limits are set on the differential branching fraction. Integrating the differential branching fraction over q2, while excluding the J /ψ and ψ(2S) regions, gives a branching fraction of B(Λ0 b → Λμ+μ−) = (0.96 ± 0.16(stat) ± 0.13(syst) ± 0.21(norm)) × 10−6, where the uncertainties are statistical, systematic and due to the normalisation mode, Λ0 b → J /ψΛ, respectively

Studies of beauty baryon decays to D0ph− and Λ+ch− final states

Decays of beauty baryons to the D 0 p h − and Λ + c h − final states (where h indicates a pion or a kaon) are studied using a data sample of p p collisions, corresponding to an integrated luminosity of 1.0     fb − 1 , collected by the LHCb detector. The Cabibbo-suppressed decays Λ 0 b → D 0 p K − and Λ 0 b → Λ + c K − are observed, and their branching fractions are measured with respect to the decays Λ 0 b → D 0 p π − and Λ 0 b → Λ + c π − . In addition, the first observation is reported of the decay of the neutral beauty-strange baryon Ξ 0 b to the D 0 p K − final state, and a measurement of the Ξ 0 b mass is performed. Evidence of the Ξ 0 b → Λ + c K − decay is also reported

Search for the Lepton-Flavor-Violating Decays Bs0→e±μ∓ and B0→e±μ∓

A search for the lepton-flavor-violating decays B 0 s → e ± μ ∓ and B 0 → e ± μ ∓ is performed with a data sample, corresponding to an integrated luminosity of 1.0     fb − 1 of p p collisions at √ s = 7     TeV , collected by the LHCb experiment. The observed number of B 0 s → e ± μ ∓ and B 0 → e ± μ ∓ candidates is consistent with background expectations. Upper limits on the branching fractions of both decays are determined to be B ( B 0 s → e ± μ ∓ ) 101     TeV / c 2 and M LQ ( B 0 → e ± μ ∓ ) > 126     TeV / c 2 at 95% C.L., and are a factor of 2 higher than the previous bounds

Observation of the Decay B+c→B0sπ+

The result of a search for the decay B + c → B 0 s π + is presented, using the B 0 s → D − s π + and B 0 s → J / ψ ϕ channels. The analysis is based on a data sample of p p collisions collected with the LHCb detector, corresponding to an integrated luminosity of 1     fb − 1 taken at a center-of-mass energy of 7 TeV, and 2     fb − 1 taken at 8 TeV. The decay B + c → B 0 s π + is observed with significance in excess of 5 standard deviations independently in both decay channels. The measured product of the ratio of cross sections and branching fraction is [ σ ( B + c ) / σ ( B 0 s ) ] × B ( B + c → B 0 s π + ) = [ 2.37 ± 0.31   ( stat ) ± 0.11   ( syst ) + 0.17 − 0.13 ( τ B + c ) ] × 10 − 3 , in the pseudorapidity range 2 < η ( B ) < 5 , where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the B + c lifetime. This is the first observation of a B meson decaying to another B meson via the weak interaction

Measurement of Form-Factor-Independent Observables in the Decay B0→K*0μ+μ−

We present a measurement of form-factor-independent angular observables in the decay B 0 → K ∗ ( 892 ) 0 μ + μ − . The analysis is based on a data sample corresponding to an integrated luminosity of 1.0     fb − 1 , collected by the LHCb experiment in p p collisions at a center-of-mass energy of 7 TeV. Four observables are measured in six bins of the dimuon invariant mass squared q 2 in the range 0.1 < q 2 < 19.0     GeV 2 / c 4 . Agreement with recent theoretical predictions of the standard model is found for 23 of the 24 measurements. A local discrepancy, corresponding to 3.7 Gaussian standard deviations is observed in one q 2 bin for one of the observables. Considering the 24 measurements as independent, the probability to observe such a discrepancy, or larger, in one is 0.5%

First observation of B¯0 → J/ψK+K- and search for B¯0 → J/ψϕ decays

The first observation of the ¯¯¯ B 0 → J / ψ K + K − decay is presented with a data sample corresponding to an integrated luminosity of 1.0     fb − 1 of p p collisions at a center-of-mass energy of 7 TeV collected with the LHCb detector. The branching fraction is measured to be B ( ¯¯¯ B 0 → J / ψ K + K − ) = ( 2.53 ± 0.31 ± 0.19 ) × 10 − 6 , where the first uncertainty is statistical and the second is systematic. An amplitude analysis of the final state in the ¯¯¯ B 0 → J / ψ K + K − decay is performed to separate resonant and nonresonant contributions in the K + K − spectrum. Evidence of the a 0 ( 980 ) resonance is reported with statistical significance of 3.9 standard deviations. The corresponding product branching fraction is measured to be B ( ¯¯¯ B 0 → J / ψ a 0 ( 980 ) , a 0 ( 980 ) → K + K − ) = ( 4.70 ± 3.31 ± 0.72 ) × 10 − 7 , yielding an upper limit of B ( ¯¯¯ B 0 → J / ψ a 0 ( 980 ) , a 0 ( 980 ) → K + K − ) < 9.0 × 10 − 7 at 90% confidence level. No evidence of the resonant decay ¯¯¯ B 0 → J / ψ ϕ is found, and an upper limit on its branching fraction is set to be B ( ¯¯¯ B 0 → J / ψ ϕ ) < 1.9 × 10 − 7 at 90% confidence level

Search for Majorana Neutrinos in B−→π+μ−μ− Decays

A search for heavy Majorana neutrinos produced in the B − → π + μ − μ − decay mode is performed using 3     fb − 1 of integrated luminosity collected with the LHCb detector in p p collisions at center-of-mass energies of 7 and 8 TeV at the LHC. Neutrinos with masses in the range 250 to 5000 MeV and lifetimes from zero to 1000 ps are probed. In the absence of a signal, upper limits are set on the branching fraction B ( B − → π + μ − μ − ) as functions of neutrino mass and lifetime. These limits are on the order of 10 − 9 for short neutrino lifetimes of 1 ps or less. Limits are also set on the coupling between the muon and a possible fourth-generation neutrino