Updated channel numbering and readout partitioning for the Silicon Tracker

The channel numbering scheme and readout partioning for the LHCb Silicon Tracker is updated to take account of changes to the detector cabling that have occurred since the start of DC'06. In addition, several typographical errors in the previous note have been corrected

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

Measurement of J/ψ polarization in pp collisions at s√=7 TeV

An angular analysis of the decay J/ψ→μ + μ − is performed to measure the polarization of prompt J/ψ mesons produced in pp collisions at s√=7 TeV . The dataset corresponds to an integrated luminosity of 0.37 fb−1 collected with the LHCb detector. The measurement is presented as a function of transverse momentum, p T, and rapidity, y, of the J/ψ meson, in the kinematic region 2<p T<15 GeV/c and 2.0<y<4.5

Measurement of resonant and CPCP components in B‾s0→J/ψπ+π−\overline{B}_s^0\rightarrow J/\psi \pi^+\pi^- decays

The resonant structure of the decay $\overline{B}_s^0\to J/\psi\pi^+\pi^-$ is studied using data corresponding to 3 fb$^{-1}$ of integrated luminosity from $pp$ collisions by the LHC and collected by the LHCb detector. Five interfering $\pi^+\pi^-$ states are required to describe the decay: $f_0(980),f_0(1500),f_0(1790),f_2(1270)$, and $f_2^{\prime}(1525)$. An alternative model including these states and a non-resonant $J/\psi \pi^+\pi^-$ 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 $CP$-odd. The $CP$-even part is found to be $<2.3$% at 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 $<7.7^{\circ}$ at 90% confidence level, consistent with a tetraquark interpretation of the $f_0(980)$ substructure