First observation of the decay B∗s2(5840)0→B∗+K− and studies of excited Bs mesons

The properties of the orbitally excited (L=1) B0s states are studied by using 1.0  fb−1 of pp collisions at s√=7  TeV collected with the LHCb detector. The first observation of the B∗s2(5840)0 meson decaying to B*+K− is reported, and the corresponding branching fraction measured relative to the B+K− decay mode. The Bs1(5830)0→B*+K− decay is observed as well. The width of the B∗s2(5840)0 state is measured for the first time, and the masses of the two states are determined with the highest precision to date. The observation of the B∗s2(5840)0→B*+K− decay favors the spin-parity assignment JP=2+ for the B∗s2(5840)0 meson. In addition, the most precise measurement of the mass difference m(B*+)−m(B+)=45.01±0.30(stat)±0.23(syst)  MeV/c2 is obtained

Measurement of CPCP violation parameters in B0→DK∗0{B}^{0}\rightarrow{}D{K}^{*0} decays

An analysis of ${B}^{0}\rightarrow{}D{K}^{*0}$ decays is presented, where $D$ represents an admixture of ${D}^{0}$ and ${\overline{D}}^{0}$ mesons reconstructed in four separate final states: ${K}^{-{}}{\pi{}}^{+}$, ${\pi{}}^{-{}}{K}^{+}$, ${K}^{+}{K}^{-{}}$ and ${\pi{}}^{+}{\pi{}}^{-{}}$. The data sample corresponds to $3.0\text{ }\text{ }{\mathrm{fb}}^{-{}1}$ of proton-proton collision, collected by the LHCb experiment. Measurements of several observables are performed, including $CP$ asymmetries. The most precise determination is presented of ${r}_{B}(D{K}^{*0})$, the magnitude of the ratio of the amplitudes of the decay ${B}^{0}\rightarrow{}D{K}^{+}{\pi{}}^{-{}}$ with a $b\rightarrow{}u$ or a $b\rightarrow{}c$ transition, in a $K\pi{}$ mass region of $\pm50 \text{ }\mathrm{MeV}/{c}^{2}$ around the ${K}^{*}(892)$ mass and for an absolute value of the cosine of the ${K}^{*0}$ helicity angle larger than 0.4

First observation of the decay B+c→J/ψK+

The decay B+c→J/ψK+ is observed for the first time using a data sample, corresponding to an integrated luminosity of 1.0 fb−1, collected by the LHCb experiment in pp collisions at a centre-of-mass energy of 7 TeV. A yield of 46 ± 12 events is reported, with a significance of 5.0 standard deviations. The ratio of the branching fraction of B+c→J/ψK+ to that of B+c→J/ψπ+ is measured to be 0.069 ± 0.019 ± 0.005, where the first uncertainty is statistical and the second is systematic

Measurement of CP asymmetry in Bs0→Ds∓K±B^0_s \rightarrow D^{\mp}_s K^{\pm} decays

We report on measurements of the time-dependent CP violating observables in $B^0_s\rightarrow D^{\mp}_s K^{\pm}$ decays using a dataset corresponding to 1.0 fb$^{-1}$ of pp collisions recorded with the LHCb detector. We find the CP violating observables $C_f=0.53\pm0.25\pm0.04$, $A^{\Delta\Gamma}_f=0.37\pm0.42\pm0.20$, $A^{\Delta\Gamma}_{\bar{f}}=0.20\pm0.41\pm0.20$, $S_f=-1.09\pm0.33\pm0.08$, $S_{\bar{f}}=-0.36\pm0.34\pm0.08$, where the uncertainties are statistical and systematic, respectively. Using these observables together with a recent measurement of the $B^0_s$ mixing phase $-2\beta_s$ leads to the first extraction of the CKM angle $\gamma$ from $B^0_s \rightarrow D^{\mp}_s K^{\pm}$ decays, finding $\gamma$ = (115$_{-43}^{+28}$)$^\circ$ modulo 180$^\circ$ at 68% CL, where the error contains both statistical and systematic uncertainties

Study of forward Z+jet production in pp collisions at s√=7 TeV

A measurement of the Z(→ μ + μ −) + jet production cross-section in pp collisions at a centre-of-mass energy s√ = 7 TeV is presented. The analysis is based on an integrated luminosity of 1.0 fb−1 recorded by the LHCb experiment. Results are shown with two jet transverse momentum thresholds, 10 and 20 GeV, for both the overall cross-section within the fiducial volume, and for six differential cross-section measurements. The fiducial volume requires that both the jet and the muons from the Z boson decay are produced in the forward direction (2.0 < η < 4.5). The results show good agreement with theoretical predictions at the second-order expansion in the coupling of the strong interaction

Evidence for exotic hadron contributions to Λb0→J/ψpπ−\Lambda_b^0 \to J/\psi p \pi^- decays

A full amplitude analysis of $\Lambda_b^0 \to J/\psi p \pi^-$ decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV $pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$. A significantly better description of the data is achieved when, in addition to the previously observed nucleon excitations $N\to p\pi^-$, either the $P_c(4380)^+$ and $P_c(4450)^+\to J/\psi p$ states, previously observed in $\Lambda_b^0 \to J/\psi p K^-$ decays, or the $Z_c(4200)^-\to J/\psi \pi^-$ state, previously reported in $B^0 \to J/\psi K^+ \pi^-$ decays, or all three, are included in the amplitude models. The data support a model containing all three exotic states, with a significance of more than three standard deviations. Within uncertainties, the data are consistent with the $P_c(4380)^+$ and $P_c(4450)^+$ production rates expected from their previous observation taking account of Cabibbo suppression

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

Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−

The angular distribution and differential branching fraction of the decay B 0→ K ∗0 μ + μ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions

Studies of beauty baryon decays to D0ph−D^0 p h^- and Λc+h−\Lambda_c^+ h^- final states

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

Search for CP violation in the decay D+→π−π+π+

A search for CP violation in the phase space of the decay D+→π−π+π+D+→π−π+π+ is reported using pp collision 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. The Dalitz plot distributions for 3.1×1063.1×106D+D+ and D−D− candidates are compared with binned and unbinned model-independent techniques. No evidence for CP violation is found