Abstract A first search for $$CP$$ CP violation in the Cabibbo-suppressed $${{{\varXi }} ^+_{c}} \rightarrow {p} {{K} ^-} {{\pi } ^+} $$ Ξ c + → p K - π + decay is performed using both a binned and ...an unbinned model-independent technique in the Dalitz plot. The studies are based on a sample of proton-proton collision data, corresponding to an integrated luminosity of $$3.0\,\text {fb} ^{-1} $$ 3.0 fb - 1 , and collected by the LHCb experiment at centre-of-mass energies of 7 and $$8\,\text {TeV} $$ 8 TeV . The data are consistent with the hypothesis of no $$CP$$ CP violation.
Abstract Using a data sample corresponding to an integrated luminosity of 2.0 $$\, \text {fb} ^{-1}$$ fb-1 , collected by the LHCb experiment, the production of the $${\eta _{c}} (1S)$$ ηc(1S) state ...in proton–proton collisions at a centre-of-mass energy of $$\sqrt{s} =13$$ s=13 $$\, \text {TeV}$$ TeV is studied in the rapidity range $$2.0< y < 4.5$$ 2.0<y<4.5 and in the transverse momentum range $$6.5< p_{\mathrm {T}} < 14.0 \, \text {GeV} $$ 6.5<pT<14.0GeV . The cross-section for prompt production of $${\eta _{c}} (1S)$$ ηc(1S) mesons relative to that of the $${J /\psi }$$ J/ψ meson is measured using the $$p $$ p $$\overline{{p}}$$ p¯ decay mode and is found to be $${\sigma _{{\eta _{c}} (1S)}/\sigma _{{{J /\psi }}} = 1.69 \pm 0.15 \pm 0.10 \pm 0.18}$$ σηc(1S)/σJ/ψ=1.69±0.15±0.10±0.18 . The quoted uncertainties are, in order, statistical, systematic and due to uncertainties on the branching fractions of the $${{J /\psi }} \!\rightarrow {p} {\overline{{p}}} $$ J/ψ→pp¯ and $${\eta _{c}} \!\rightarrow {p} {\overline{{p}}} $$ ηc→pp¯ decays. The prompt $${\eta _{c}} (1S)$$ ηc(1S) production cross-section is determined to be $${\sigma _{{\eta _{c}} (1S)} = 1.26 \pm 0.11\pm 0.08\pm 0.14 \,\upmu \text {b}}$$ σηc(1S)=1.26±0.11±0.08±0.14μb , where the last uncertainty includes that on the $${J /\psi }$$ J/ψ meson cross-section. The ratio of the branching fractions of $$b $$ b -hadron decays to the $${\eta _{c}} (1S)$$ ηc(1S) and $${J /\psi }$$ J/ψ states is measured to be $${{\mathcal {B}} _{{b} \!\rightarrow {\eta _{c}} X}/{\mathcal {B}} _{{b} \!\rightarrow {{J /\psi }} X} = 0.48 \pm 0.03 \pm 0.03 \pm 0.05}$$ Bb→ηcX/Bb→J/ψX=0.48±0.03±0.03±0.05 , where the last uncertainty is due to those on the branching fractions of the $${{J /\psi }} \!\rightarrow {p} {\overline{{p}}} $$ J/ψ→pp¯ and $${\eta _{c}} \!\rightarrow {p} {\overline{{p}}} $$ ηc→pp¯ decays. The difference between the $${J /\psi }$$ J/ψ and $${\eta _{c}} (1S)$$ ηc(1S) masses is also determined to be $$113.0 \pm 0.7 \pm 0.1 \, \text {MeV} $$ 113.0±0.7±0.1MeV , which is the most precise single measurement of this quantity to date.
Abstract The cross-sections of $$\psi {(2S)}$$ ψ(2S) meson production in proton-proton collisions at $$\sqrt{s} =13\text { TeV} $$ s=13TeV are measured with a data sample collected by the LHCb ...detector corresponding to an integrated luminosity of $$275\text { pb} ^{-1} $$ 275pb-1 . The production cross-sections for prompt $$\psi {(2S)}$$ ψ(2S) mesons and those for $$\psi {(2S)}$$ ψ(2S) mesons from b-hadron decays ($${\psi {(2S)}} \text{-from- }{b} $$ ψ(2S)-from-b ) are determined as functions of the transverse momentum, $$p_{\mathrm {T}}$$ pT , and the rapidity, y, of the $$\psi {(2S)}$$ ψ(2S) meson in the kinematic range $$2<p_{\mathrm {T}} <20\text { GeV/}c $$ 2<pT<20GeV/c and $$2.0<y<4.5$$ 2.0<y<4.5 . The production cross-sections integrated over this kinematic region are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},13\text { TeV})\\&\quad =1.430\pm 0.005\text { (stat)} \pm 0.099\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},13\text { TeV})\\&\quad =0.426\pm 0.002\text { (stat)} \pm 0.030\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$ σ(promptψ(2S),13TeV)=1.430±0.005(stat)±0.099(syst)μb,σ(ψ(2S)-from-b,13TeV)=0.426±0.002(stat)±0.030(syst)μb. A new measurement of $$\psi {(2S)}$$ ψ(2S) production cross-sections in pp collisions at $$\sqrt{s}=7\text { TeV} $$ s=7TeV is also performed using data collected in 2011, corresponding to an integrated luminosity of $$614\text { pb} ^{-1} $$ 614pb-1 . The integrated production cross-sections in the kinematic range $$3.5<p_{\mathrm {T}} <14\text { GeV/}c $$ 3.5<pT<14GeV/c and $$2.0<y<4.5$$ 2.0<y<4.5 are $$\begin{aligned} \begin{aligned}&\sigma (\text{ prompt } {\psi {(2S)}},7\text { TeV})\\&\quad =0.471\pm 0.001\text { (stat)} \pm 0.025\text { (syst)} \,\upmu \text {b} ,\\&\sigma ({\psi {(2S)}} \text{-from- }{b},7\text { TeV})\\&\quad =0.126\pm 0.001\text { (stat)} \pm 0.008\text { (syst)} \,\upmu \text {b} . \end{aligned} \end{aligned}$$ σ(promptψ(2S),7TeV)=0.471±0.001(stat)±0.025(syst)μb,σ(ψ(2S)-from-b,7TeV)=0.126±0.001(stat)±0.008(syst)μb. All results show reasonable agreement with theoretical calculations.
Abstract A search for $$C\!P$$ CP violation in charmless four-body decays of $${\varLambda } ^0_{b} $$ Λb0 and $${\varXi } ^0_{b} $$ Ξb0 baryons with a proton and three charged mesons in the final ...state is performed. To cancel out production and detection charge-asymmetry effects, the search is carried out by measuring the difference between the $$C\!P$$ CP asymmetries in a charmless decay and in a decay with an intermediate charmed baryon with the same particles in the final state. The data sample used was recorded in 2011 and 2012 with the LHCb detector and corresponds to an integrated luminosity of $$3 \text { fb} ^{-1} $$ 3fb-1 . A total of 18 $$C\!P$$ CP asymmetries are considered, either accounting for the full phase space of the decays or exploring specific regions of the decay kinematics. No significant $$C\!P$$ CP -violation effect is observed in any of the measurements.
Abstract A search for the rare leptonic decay $${{{B} ^+}} \!\rightarrow {\mu ^+} {\mu ^-} {\mu ^+} {{\upnu } _\mu } $$ B+→μ+μ-μ+νμ is performed using proton-proton collision data corresponding to an ...integrated luminosity of $$4.7 \, {\hbox {fb}}^{-1}$$ 4.7fb-1 collected by the LHCb experiment. The search is carried out in the region where the lowest of the two $${\mu ^+\mu ^-} $$ μ+μ- mass combinations is below $$980 {\mathrm {\,MeV\!/}c^2} $$ 980MeV/c2 . The data are consistent with the background-only hypothesis and an upper limit of $$1.6 \times 10^{-8}$$ 1.6×10-8 at 95% confidence level is set on the branching fraction in the stated kinematic region.
Abstract The decay-time-dependent $$CP$$ CP asymmetry in $${{B} ^0_{s}} \rightarrow J/\psi {{K} ^+} {{K} ^-} $$ Bs0→J/ψK+K- decays is measured using proton–proton collision data, corresponding to an ...integrated luminosity of $$1.9\,\mathrm{fb}^{-1} $$ 1.9fb-1 , collected with the LHCb detector at a centre-of-mass energy of $$13\,\mathrm {TeV}$$ 13TeV in 2015 and 2016. Using a sample of approximately 117 000 signal decays with an invariant $${{K} ^+} {{K} ^-} $$ K+K- mass in the vicinity of the $$\phi (1020)$$ ϕ(1020) resonance, the $$CP$$ CP -violating phase $$\phi _s$$ ϕs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the $${{B} ^0_{s}} $$ Bs0 -$${{\overline{B}{}} {}^0_{s}} $$ B¯s0 system, $$\Delta \Gamma _s$$ ΔΓs . The difference of the average $${{B} ^0_{s}} $$ Bs0 and $${{B} ^0} $$ B0 meson decay widths, $$\Gamma _s-\Gamma _d$$ Γs-Γd , is determined using in addition a sample of $${{B} ^0} \rightarrow J/\psi {{K} ^+} {{\pi } ^-} $$ B0→J/ψK+π- decays. The values obtained are $$\phi _s = -0.083\pm 0.041\pm 0.006\mathrm { \,rad} $$ ϕs=-0.083±0.041±0.006rad , $$\Delta \Gamma _s = 0.077 \pm 0.008 \pm 0.003 {\mathrm { \,ps^{-1}}} $$ ΔΓs=0.077±0.008±0.003ps-1 and $$\Gamma _s-\Gamma _d = -0.0041 \pm 0.0024 \pm 0.0015{\mathrm { \,ps^{-1}}} $$ Γs-Γd=-0.0041±0.0024±0.0015ps-1 , where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of these quantities to date and are consistent with expectations based on the Standard Model and with a previous LHCb analysis of this decay using data recorded at centre-of-mass energies 7 and 8 TeV. Finally, the results are combined with recent results from $${{B} ^0_{s}} \rightarrow J/\psi {{\pi } ^+} {{\pi } ^-} $$ Bs0→J/ψπ+π- decays obtained using the same dataset as this analysis, and with previous independent LHCb results.
Abstract The branching fraction and direct $$C\!P$$ CP asymmetry of the decay $${{{B} ^+}} \!\rightarrow {{J /\psi }} {{\rho } ^+} $$ B+→J/ψρ+ are measured using proton-proton collision data ...collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV, corresponding to a total integrated luminosity of 3$$\,\text{ fb }^{-1}$$ fb-1 . The following results are obtained: $$\begin{aligned} \mathcal {B}({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= (3.81^{+0.25}_{-0.24} \pm 0.35) \times 10^{-5},\\ \mathcal {A}^{{C\!P}} ({{B} ^+} \!\rightarrow {{J /\psi }} {{\rho } ^+} )&= -0.045^{+0.056}_{-0.057} \pm 0.008, \end{aligned}$$ B(B+→J/ψρ+)=(3.81-0.24+0.25±0.35)×10-5,ACP(B+→J/ψρ+)=-0.045-0.057+0.056±0.008, where the first uncertainties are statistical and the second systematic. Both measurements are the most precise to date.
Abstract A search for radiative decay of B s 0 $$ {B}_s^0 $$ mesons to orbitally excited K + K − states is performed using proton proton collisions recorded by the LHCb experiment, corresponding to ...an integrated luminosity of 9 fb −1. The dikaon spectrum in the mass range m KK < 2400 MeV/c 2 is dominated by the ϕ(1020) resonance that accounts for almost 70% of the decay rate. Considering the possible contributions of f 2(1270), f 2 ′ $$ {f}_2^{\prime } $$ (1525) and f 2(2010) meson states, the overall tensor contribution to the amplitude is measured to be F f 2 = 16.8 ± 0.5 stat . ± 0.7 syst . % , $$ {\mathcal{F}}_{\left\{{f}_2\right\}}=16.8\pm 0.5\left(\textrm{stat}.\right)\pm 0.7\left(\textrm{syst}.\right)\%, $$ mostly dominated by the f 2 ′ $$ {f}_2^{\prime } $$ (1525) state. Several statistically equivalent solutions are obtained for the detailed resonant structure depending on whether the smaller amplitudes interfere destructively or constructively with the dominant amplitude. The preferred solution that corresponds to the lowest values of the fit fractions along with constructive interference leads to the relative branching ratio measurement B B s 0 → f 2 ′ γ B B s 0 → ϕγ = 19.4 − 0.8 + 0.9 stat . − 0.5 + 1.4 syst . ± 0.5 B % , $$ \frac{\mathcal{B}\left({B}_s^0\to {f}_2^{\prime}\gamma \right)}{\mathcal{B}\left({B}_s^0\to \phi \gamma \right)}={19.4}_{-0.8}^{+0.9}{\left(\textrm{stat}.\right)}_{-0.5}^{+1.4}\left(\textrm{syst}.\right)\pm 0.5\left(\mathcal{B}\right)\%, $$ where the last uncertainty is due to the ratio of measured branching fractions to the K + K − final state. This result represents the first observation of the radiative B s 0 → f 2 ′ 1525 γ $$ {B}_s^0\to {f}_2^{\prime }(1525)\gamma $$ decay, which is the second radiative transition observed in the B s 0 $$ {B}_s^0 $$ sector.
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