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Creators/Authors contains: "Durham, J. M."

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  1. A<sc>bstract</sc> An angular analysis ofB0→ K*0e+edecays is presented using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The analysis is performed in the region of the dilepton invariant mass squared of 1.1–6.0 GeV2/c4. In addition, a test of lepton flavour universality is performed by comparing the obtained angular observables with those measured inB0→ K*0μ+μdecays. In general, the angular observables are found to be consistent with the Standard Model expectations as well as with global analyses of otherb → sℓ+processes, whereℓis either a muon or an electron. No sign of lepton-flavour-violating effects is observed. 
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    Free, publicly-accessible full text available June 1, 2026
  2. A<sc>bstract</sc> A search for the decay$$ {B}_c^{+} $$ B c + → χc1(3872)π+is reported using proton-proton collision data collected with the LHCb detector between 2011 and 2018 at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. No significant signal is observed. Using the decay$$ {B}_c^{+} $$ B c + →ψ(2S)π+as a normalisation channel, an upper limit for the ratio of branching fractions$$ {\mathcal{R}}_{\psi (2S)}^{\chi_{c1}(3872)}=\frac{{\mathcal{B}}_{B_c^{+}\to {\chi}_{c1}(3872){\pi}^{+}}}{{\mathcal{B}}_{B_c^{+}\to \psi (2S){\pi}^{+}}}\times \frac{{\mathcal{B}}_{\chi_{c1}(3872)\to J/\psi {\pi}^{+}{\pi}^{-}}}{{\mathcal{B}}_{\psi (2S)\to J/\psi {\pi}^{+}{\pi}^{-}}}<0.05(0.06), $$ R ψ 2 S χ c 1 3872 = B B c + χ c 1 3872 π + B B c + ψ 2 S π + × B χ c 1 3872 J / ψ π + π B ψ 2 S J / ψ π + π < 0.05 0.06 , is set at the 90 (95)% confidence level. 
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    Free, publicly-accessible full text available June 1, 2026
  3. The branching fraction of the decay B + ψ ( 2 S ) ϕ ( 1020 ) K + , relative to the topologically similar decay B + J / ψ ϕ ( 1020 ) K + , is measured using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb 1 . The ratio is found to be 0.061 ± 0.004 ± 0.009 , where the first uncertainty is statistical and the second systematic. Using the world-average branching fraction for B + J / ψ ϕ ( 1020 ) K + , the branching fraction for the decay B + ψ ( 2 S ) ϕ ( 1020 ) K + is found to be ( 3.0 ± 0.2 ± 0.5 ± 0.2 ) × 10 6 , where the first uncertainty is statistical, the second systematic, and the third is due to the branching fraction of the normalization channel. © 2025 CERN, for the LHCb Collaboration2025CERN 
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    Free, publicly-accessible full text available May 1, 2026
  4. A search for C P violation in Λ b 0 p K and Λ b 0 p π decays is presented using the full Run 1 and Run 2 data samples of p p collisions collected with the LHCb detector, corresponding to an integrated luminosity of 9 fb 1 at center-of-mass energies of 7, 8, and 13 TeV. For the Run 2 data sample, the C P -violating asymmetries are measured to be A C P p K = ( 1.4 ± 0.7 ± 0.4 ) % and A C P p π = ( 0.4 ± 0.9 ± 0.4 ) % , where the first uncertainty is statistical and the second is systematic. Following significant improvements in the evaluation of systematic uncertainties compared to the previous LHCb measurement, the Run 1 dataset is reanalyzed to update the corresponding results. When combining the Run 2 and updated Run 1 measurements, the final results are found to be A C P p K = ( 1.1 ± 0.7 ± 0.4 ) % and A C P p π = ( 0.2 ± 0.8 ± 0.4 ) % , constituting the most precise measurements of these asymmetries to date. © 2025 CERN, for the LHCb Collaboration2025CERN 
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    Free, publicly-accessible full text available May 1, 2026
  5. A<sc>bstract</sc> TheΥ(2S) andΥ(3S) production cross-sections are measured relative to that of theΥ(1S) meson, as a function of charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy of 13 TeV. The measurement uses data collected by the LHCb experiment in 2018 corresponding to an integrated luminosity of 2 fb−1. Both theΥ(2S)-to-Υ(1S) andΥ(3S)-to-Υ(1S) cross-section ratios are found to decrease significantly as a function of event multiplicity, with theΥ(3S)-to-Υ(1S) ratio showing a steeper decline towards high multiplicity. This hierarchy is qualitatively consistent with the comover model predictions, indicating that final-state interactions play an important role in bottomonia production in high-multiplicity events. 
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    Free, publicly-accessible full text available May 1, 2026
  6. A study is presented of B + K S 0 K π + K + and B + K S 0 K + π K + decays based on the analysis of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb 1 . The K S 0 K π invariant-mass distributions of both B + decay modes show, in the m ( K S 0 K π ) < 1.85 GeV mass region, large activity which is resolved using an amplitude analysis. A simple model, where J P C amplitudes are described by multiple Breit-Wigner functions with appropriate angular distributions, provides a good description of the experimental data. In this approach a complex mixture of J P C = 0 + , 1 + + and 1 + amplitudes is observed that is dominated by η ( 1405 ) , η ( 1470 ) , η ( 1760 ) , f 1 ( 1285 ) , f 1 ( 1420 ) and h 1 ( 1405 ) resonances. The K S 0 K π Dalitz plots are dominated by asymmetric crossing K * K ¯ bands which are different for the two B + decay modes. This is due to a different interference pattern between the 1 + + and 1 + amplitudes in the two channels. Branching fractions are measured for each resonant contribution. © 2025 CERN, for the LHCb Collaboration2025CERN 
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    Free, publicly-accessible full text available May 1, 2026
  7. The first test of lepton flavor universality between muons and electrons using B + K + π + π + ( = e , μ ) decays is presented. The measurement is performed with data from proton-proton collisions collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb 1 . The ratio of branching fractions between B + K + π + π e + e and B + K + π + π μ + μ decays is measured in the dilepton invariant-mass-squared range 1.1 < q 2 < 7.0 GeV 2 / c 4 and is found to be R K π π 1 = 1.3 1 0.17 + 0.18 ( stat ) 0.09 + 0.12 ( syst ) , in agreement with the standard model prediction. The first observation of the B + K + π + π e + e decay is also reported. © 2025 CERN, for the LHCb Collaboration2025CERN 
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    Free, publicly-accessible full text available May 1, 2026
  8. A search for D 0 meson decays to the π + π e + e and K + K e + e final states is reported using a sample of proton-proton collisions collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb 1 . The decay D 0 π + π e + e is observed for the first time when requiring that the two electrons are consistent with coming from the decay of a ϕ or ρ 0 / ω meson. The corresponding branching fractions are measured relative to the D 0 K π [ e + e ] ρ 0 / ω decay, where the two electrons are consistent with coming from the decay of a ρ 0 or ω meson. No evidence is found for the D 0 K + K e + e decay and world-best limits are set on its branching fraction. The results are compared to, and found to be consistent with, the branching fractions of the D 0 π + π μ + μ and D 0 K + K μ + μ decays recently measured by LHCb and confirm lepton universality at the current precision. © 2025 CERN, for the LHCb Collaboration2025CERN 
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    Free, publicly-accessible full text available May 1, 2026
  9. The first measurement of the C P asymmetry of the decay rate ( A C P ) and the C P average ( Σ A FB ) and C P asymmetry ( Δ A FB ) of the forward-backward asymmetry in the muon system of Λ c + p μ + μ decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13 TeV, which corresponds to an integrated luminosity of 5.4 fb 1 . The asymmetries are measured in two regions of dimuon mass near the  ϕ -meson mass peak. The dimuon-mass integrated results are A C P = ( 1.1 ± 4.0 ± 0.5 ) % , Σ A FB = ( 3.9 ± 4.0 ± 0.6 ) % , Δ A FB = ( 3.1 ± 4.0 ± 0.4 ) % , where the first uncertainty is statistical and the second systematic. The results are consistent with the conservation of C P symmetry and the Standard Model expectations. © 2025 CERN, for the LHCb Collaboration2025CERN 
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    Free, publicly-accessible full text available May 1, 2026
  10. Abstract This paper presents the first measurement of$$\psi {(2S)}$$ ψ ( 2 S ) and$$\chi _{c1}(3872)$$ χ c 1 ( 3872 ) meson production within fully reconstructed jets. Each quarkonium state (tag) is reconstructed via its decay to the$${{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} $$ J / ψ ($$\rightarrow $$ $$\mu ^+\mu ^-$$ μ + μ - )$$\pi ^+\pi ^-$$ π + π - final state in the forward region using proton-proton collision data collected by the LHCb experiment at the center-of-mass-energy of$$13\text {TeV} $$ 13 TeV in 2016, corresponding to an integrated luminosity of$$1.64\,\text {\,fb} ^{-1} $$ 1.64 \,fb - 1 . The fragmentation function, presented as the ratio of the quarkonium-tag transverse momentum to the full jet transverse momentum ($$p_{\textrm{T}} (\text {tag})/p_{\textrm{T}} (\text {jet})$$ p T ( tag ) / p T ( jet ) ), is measured differentially in$$p_{\textrm{T}} (\text {jet})$$ p T ( jet ) and$$p_{\textrm{T}} (\text {tag})$$ p T ( tag ) bins. The distributions are separated into promptly produced quarkonia from proton-proton collisions and quarkonia produced from displacedb-hadron decays. While the displaced quarkonia fragmentation functions are in general well described by parton-shower predictions, the prompt quarkonium distributions differ significantly from fixed-order non-relativistic QCD (NRQCD) predictions followed by a QCD parton shower. 
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    Free, publicly-accessible full text available May 1, 2026