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.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract A Dalitz plot analysis of $${{B} ^0} \!\rightarrow \eta _c(1S) {{K} ^+} {{\pi } ^-} $$ B0→ηc(1S)K+π- decays is performed using data samples of pp collisions collected with the $$\text{ LHCb ...} $$ LHCb detector at centre-of-mass energies of $${\sqrt{s}} =7,~8$$ s=7,8 and $$13{\,\mathrm {Te}\mathrm {V}} $$ 13TeV , corresponding to a total integrated luminosity of $$4.7 \,\text{ fb }^{-1} $$ 4.7fb-1 . A satisfactory description of the data is obtained when including a contribution representing an exotic $$\eta _c(1S) \pi ^-$$ ηc(1S)π- resonant state. The significance of this exotic resonance is more than three standard deviations, while its mass and width are $$4096 \pm 20~^{+18}_{-22} \,\mathrm {Me}\mathrm {V} $$ 4096±20-22+18MeV and $$152 \pm 58~^{+60}_{-35} \,\mathrm {Me}\mathrm {V} $$ 152±58-35+60MeV , respectively. The spin-parity assignments $$J^P=0^+$$ JP=0+ and $$J^{P}=1^-$$ JP=1- are both consistent with the data. In addition, the first measurement of the $${{B} ^0} \!\rightarrow \eta _c(1S) {{K} ^+} {{\pi } ^-} $$ B0→ηc(1S)K+π- branching fraction is performed and gives $$\begin{aligned} \displaystyle \mathcal {B}({{B} ^0} \!\rightarrow \eta _c(1S) {{K} ^+} {{\pi } ^-} ) = (5.73 \pm 0.24 \pm 0.13 \pm 0.66) \times 10^{-4}, \end{aligned}$$ B(B0→ηc(1S)K+π-)=(5.73±0.24±0.13±0.66)×10-4, where the first uncertainty is statistical, the second systematic, and the third is due to limited knowledge of external branching fractions.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Amplitude models are constructed to describe the resonance structure of $${D^{0}\rightarrow K^{-}\pi ^{+}\pi ^{+}\pi ^{-}}$$ D0→K-π+π+π- and $${D^{0} \rightarrow K^{+}\pi ^{-}\pi ^{-}\pi ...^{+}}$$ D0→K+π-π-π+ decays using pp collision data collected at centre-of-mass energies of 7 and 8 TeV with the LHCb experiment, corresponding to an integrated luminosity of 3.0 $$fb^{-1}$$ fb-1 . The largest contributions to both decay amplitudes are found to come from axial resonances, with decay modes $$D^{0} \rightarrow a_1(1260)^{+} K^{-}$$ D0→a1(1260)+K- and $$D^{0} \rightarrow K_1(1270/1400)^{+} \pi ^{-}$$ D0→K1(1270/1400)+π- being prominent in $${D^{0}\rightarrow K^{-}\pi ^{+}\pi ^{+}\pi ^{-}}$$ D0→K-π+π+π- and $$D^{0}\rightarrow K^{+}\pi ^{-}\pi ^{-}\pi ^{+}$$ D0→K+π-π-π+ , respectively. Precise measurements of the lineshape parameters and couplings of the $$a_1(1260)^{+}$$ a1(1260)+ , $$K_1(1270)^{-}$$ K1(1270)- and $$K(1460)^{-}$$ K(1460)- resonances are made, and a quasi model-independent study of the $$K(1460)^{-}$$ K(1460)- resonance is performed. The coherence factor of the decays is calculated from the amplitude models to be $$R_{K3\pi } = 0.459\pm 0.010\,(\mathrm {stat}) \pm 0.012\,(\mathrm {syst}) \pm 0.020\,(\mathrm {model})$$ RK3π=0.459±0.010(stat)±0.012(syst)±0.020(model) , which is consistent with direct measurements. These models will be useful in future measurements of the unitary-triangle angle $$\gamma $$ γ and studies of charm mixing and $$C\!P$$ CP violation.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract A search for the decay $${{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-$$ KS0→μ+μ- is performed, based on a data sample of proton-proton collisions corresponding to an ...integrated luminosity of $$3\,\text{ fb }^{-1} $$ 3fb-1 , collected by the LHCb experiment at centre-of-mass energies of 7 and 8$$\mathrm {\,TeV}$$ TeV . The observed yield is consistent with the background-only hypothesis, yielding a limit on the branching fraction of $$\mathcal{B}({{K} ^0_{\mathrm { \scriptscriptstyle S}}} \rightarrow \mu ^+\mu ^-) < 0.8~(1.0) \times 10^{-9}$$ B(KS0→μ+μ-)<0.8(1.0)×10-9 at $$90\%~(95\%)$$ 90%(95%) confidence level. This result improves the previous upper limit on the branching fraction by an order of magnitude.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract A measurement of the time-dependent CP-violating asymmetry in B s 0 → ϕϕ $$ {B}_s^0\to \phi \phi $$ decays is presented. Using a sample of proton-proton collision data corresponding to an ...integrated luminosity of 5.0 fb −1 collected by the LHCb experiment at centre-of-mass energies s $$ \sqrt{s} $$ = 7 TeV in 2011, 8 TeV in 2012 and 13 TeV in 2015 and 2016, a signal yield of around 9000 B s 0 → ϕϕ $$ {B}_s^0\to \phi \phi $$ decays is obtained. The CP-violating phase ϕ s s s ¯ s $$ {\phi}_s^{s\overline{s}s} $$ is measured to be −0.073 ± 0.115(stat) ± 0.027(syst) rad, under the assumption it is independent of the helicity of the ϕϕ decay. In addition, the CP-violating phases of the transverse polarisations under the assumption of CP conservation of the longitudinal phase are measured. The helicity-independent direct CP-violation parameter is also measured, and is found to be |λ| = 0.99 ± 0.05(stat) ± 0.01(syst). In addition, T-odd triple-product asymmetries are measured. The results obtained are consistent with the hypothesis of CP conservation in b ¯ → s ¯ s s ¯ s $$ \overline{b}\to \overline{s}s\overline{s}s $$ transitions. Finally, a limit on the branching fraction of the B 0 → ϕϕ decay is determined to be B B 0 → ϕϕ < 2.7 × 10 − 8 $$ \mathcal{B}\left({B}^0\to \phi \phi \right)<2.7\times {10}^{-8} $$ at 90 % confidence level.
Abstract Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector between 2011 and 2018, a new narrow charmonium state, the X(3842) ...resonance, is observed in the decay modes X 3842 → D 0 D ¯ 0 $$ \mathrm{X}(3842)\to {D}^0{\overline{D}}^0 $$ and X(3842) → D + D −. The mass and the natural width of this state are measured to be m X 3842 = 3842.71 ± 0.16 ± 0.12 M e V / c 2 , Γ X 3842 = 2.79 ± 0.51 ± 0.35 M e V , $$ \begin{array}{l}{m}_{X(3842)}=3842.71\pm 0.16\pm 0.12\ MeV/{c}^2,\hfill \\ {}{\varGamma}_{X(3842)}=2.79\pm 0.51\pm 0.35\ MeV,\hfill \end{array} $$ where the first uncertainty is statistical and the second is systematic. The observed mass and narrow natural width suggest the interpretation of the new state as the unobserved (spin-3 ψ 3 13D3) charmonium state. In addition, prompt hadroproduction of the ψ(3770) and χ 2(3930) states is observed for the first time, and the parameters of these states are measured to be m ψ 3770 = 3778.1 ± 0.7 ± 0.6 M e V / c 2 , m χ 2 3930 = 3921.9 ± 0.6 ± 0.2 M e V / c 2 , Γ χ 2 3930 = 36.6 ± 1.9 ± 0.9 M e V , $$ \begin{array}{l}{m}_{\psi (3770)}=3778.1\pm 0.7\pm 0.6\ MeV/{c}^2,\hfill \\ {}{m}_{\chi_2(3930)}=3921.9\pm 0.6\pm 0.2\ MeV/{c}^2,\hfill \\ {}{\varGamma}_{\chi_2(3930)}=36.6 \pm 1.9 \pm 0.9\ MeV,\hfill \end{array} $$ where the first uncertainty is statistical and the second is systematic.
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