LHCb Experiment

@lhcb.bsky.social

The LHCb experiment at CERN. cern.ch/lhcb-public.

Search for the decays B(c)⁺→μ⁺νγ - No evidence for an excess of events over background is observed for either signal decay. This constitutes the first search for these decays at a hadron collider and the first experimental investigation of the Bc⁺→μ⁺νγ decay to date. arxiv.org/abs/2607.12825

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Differential measurement of the branching fraction and CP asymmetry of the decay B⁺→π⁺μ⁺μ⁻ - The measured branching fractions are compatible with the predictions of the Standard Model, with consistency varying between 1.4σ and 3.8σ depending on the model assumptions. arxiv.org/abs/2606.23646

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Measurement of the ratio of branching fractions B(Bc⁺→J/ψτ⁺ν)/B(Bc⁺→J/ψμ⁺ν) - The measured value is found to be R(J/ψ)=0.51±0.12(stat)±0.08(syst), which is within 1.8 standard deviations of the predictions from the Standard Model assuming lepton flavor universality. arxiv.org/pdf/2606.10018

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Associated Z + J/ψ production as a probe of multiparton interactions in the forward region - The measured cross-section is 5.5±1.5 pb, significantly exceeding the single-parton scattering expectation of 0.10±0.08 pb, indicating that multiparton interactions dominate. arxiv.org/abs/2606.05786

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Study of nuclear effects on charm production in light-ion collisions - The onset of nuclear effects in light-ion collisions is studied by measuring the ratio of D meson production between NeNe and OO collisions at a center-of-mass energy per nucleon pair of 5.36TeV. arxiv.org/abs/2605.27273

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Measurement of γ using B⁺→ DK⁺ and B⁺→ Dπ⁺ decays with D→Ks⁰π⁺π⁻ and D→Ks⁰K⁺K⁻ - A measurement of the CKM angle γ is performed with a data sample collected during 2024 by the upgraded LHCb experiment. The CKM angle γ is determined to be γ=(68.1±6.7)∘. arxiv.org/abs/2605.03501

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First evidence of the decay B⁺→K⁺e⁺e⁻ - A signal excess with a significance of 3.2σ is observed and the branching fraction is measured to be BR(B⁺→K⁺e⁺e⁻)=(2.4+0.9−0.8+0.4−0.2)×10⁻⁸, where the first set of uncertainties is statistical and the second is systematic arxiv.org/abs/2604.26784

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Observation of a new excited charm-strange meson Dₛ₁(2933)⁺ in B⁰→D⁺D⁻K⁺π⁻ decays - Its Breit-Wigner mass and width are measured to be 2933 MeV and 72 MeV, respectively, and its spin-parity 1⁺. This new meson is a candidate for a Dₛ(2P₁)⁺ state. arxiv.org/abs/2604.21257

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Measurement of inclusive production of charmonium states in b-hadron decays via their decay into ϕϕ - The inclusive production of the ηc(1S), ηc(2S) and χc charmonium states in b-hadron decays is studied with LHCb Run~2 data using charmonia decays to ϕϕ pairs. arxiv.org/abs/2604.11123

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Test of lepton flavour universality with B⁰→ K*⁰ℓ⁺ℓ⁻ decays at large dilepton invariant mass - The ratio of branching fractions between the muon and electron channels is measured to be 1.08+0.14−0.12(stat) ±0.07(syst) for a dilepton-invariant-mass squared above 14.0 GeV² arxiv.org/abs/2604.08631

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Search for the lepton-flavour violating decays B⁺→π⁺μ⁺e⁻ and B⁺→π⁺μ⁻e⁺ - No signal is observed and an upper limit on the branching fraction is set at <1.8×10⁻⁹ at the 90% confidence level, two orders of magnitude more restrictive than the current world average. arxiv.org/abs/2604.08396

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Search for the decays Bₛ⁰→J/ψγ at LHCb - Assuming no contribution from B⁰→J/ψγ decay, an upper limit is set on the branching fraction B(Bₛ⁰→J/ψγ)<2.9× 10⁻⁶. If no contribution from Bₛ⁰→J/ψγ decay is assumed, the limit is B(B⁰→J/ψγ)<2.5×10⁻⁶ at the 90% confidence level. arxiv.org/pdf/2604.02933

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Measurement of CP asymmetries in B̅⁰→Dₛ⁻D⁺ and B̅⁰ₛ→Dₛ⁺D⁻ decays - The measurements are found to be ACP(B̅⁰→Dₛ⁻D⁺) = 0.0009±0.0053±0.0040, ACP(B̅⁰ₛ→Dₛ⁺D⁻ ) = 0.103±0.053±0.010, This is the first measurement of this asymmetry in B̅⁰ₛ decays. arxiv.org/abs/2603.28132

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