LHCb Experiment

Observation of the Tcc(4430)⁻ state in B⁰→D*⁻D⁰K⁺ decays - This corresponds to the first observation of the Tcc(4430)⁻→D*⁻D⁰decay. The measured properties of the Tcc(4430)⁻ state are consistent with those previously measured in its decay to the ψ(2S)π⁻final state. arxiv.org/abs/2610.35239

Observation of the Ξb⁻→Ξ⁻μ⁺μ⁻ and study of the Ξb⁻→Ξ⁻ψ(2S) decays - The integrated value of B(Ξb⁻→Ξ⁻μ⁺μ⁻) is measured to be (118±24±7±38)×10⁻⁸. The ratio of the branching fractions of the Ξb⁻→Ξ⁻ψ(2S) and the Ξb⁻→Ξ⁻J/ψ decays is measured to be 0.491±0.041±0.019. arxiv.org/abs/2610.22452

Studying beautiful flavour transitions ✨ @cmsexperiment.bsky.social and @lhcb.bsky.social researchers #AtCERN have released their latest results on the rare transformation of a beauty quark into a strange quark and two muons. Read more about it: home.cern/studying-bea...

Branching fraction measurement of the decay B⁰→ K⁺π⁻μ⁺μ⁻ at high dihadron mass arxiv.org/abs/2610.14156 - The results represent the first differential measurement of the branching fraction across m(Kπ), and the first observation of the decay within this region above the J/ψ resonance.

Energy-energy correlators within Z-tagged jets in proton-proton collisions at √s = 13 TeV - The results support universality of the confinement scale for light-quark-initiated jets across collision systems and the reported transverse momentum scale of the jet. arxiv.org/abs/2610.14221

Discovery of an unexpectedly light and narrow beauty-strange state - It exhibits a narrow natural width and a substantial mass deficit compared to the conventional quark model predictions. This result marks the first observation of a nonconventional single-beauty hadron. arxiv.org/abs/2609.25178

Measurement of the Ωb⁻ baryon lifetime - The Ωb⁻ lifetime is 1.751±0.089±0.022 ps, where the uncertainties are statistical and systematic. This measurement improves on the precision of the Ωb⁻ lifetime by about a factor of two over the previous world average. arxiv.org/abs/2609.25370

First measurement of the forward rapidity dependence of W boson transverse helicity fractions - The results show a strong rapidity dependence and agree with NLO SM predictions, providing the first determination of the W transverse helicity fractions in the forward region. arxiv.org/abs/2609.22555

Observation of the doubly charmed baryon Ωcc⁺ - A peaking structure with a global significance of 8.7σ is observed in the Ωc⁰π⁺mass spectrum at a mass of 3725.9±1.0±0.2±0.4(lifetime)±0.6(ext) MeV arxiv.org/abs/2609.21921

Observation of Ξb⁰→Ξ⁰J/ψ and evidence for Ξb⁰→Ξ⁰ψ(2S) decays - The Ξ⁰ hyperon is fully reconstructed for the first time at an LHC experiment, which is achieved using the Ξ⁰→Λπ⁰ decay. arxiv.org/abs/2609.15251

Branching fraction measurements of η and η′(958) anomalous decays - This marks the first experimental search for the η′(958)→μ⁺μ⁻ decay, and the most precise measurement of the branching fraction B(η→μ⁺μ⁻) to date. arxiv.org/abs/2609.02973

Stringent limits on CPT- and Lorentz-invariance violation from Bₛ⁰ meson decays - Without assuming Lorentz-invariance violation, the CPT-violating parameter zis measured to be Re(z)=0.018±0.016±0.003 and Im(z)=0.003±0.004±0.002. arxiv.org/abs/2609.02475

First measurement of the ratio of ψ(2S)-to-J/ψ inclusive production in pAr and pp collisions at √s=113GeV with SMOG2 - Data samples were collected during argon and hydrogen gas injections in the SMOG2 storage cell, resulting in pAr and pp collisions, respectively. arxiv.org/abs/2608.30534

Observation of the Ξc⁰→ pK⁻ decay and measurement of its decay asymmetry - Using the decay chain Ξb⁻→Ξc⁰(→ pK⁻)π⁻, the decay asymmetry parameter of the Ξc⁰→ pK⁻ decay is determined to be 0.32±0.15±0.01. arxiv.org/abs/2608.27894

Angular analysis of the decay Λb⁰→Λ(1520)μ⁺μ⁻ - The leptonic forward-backward asymmetry and the angular observable S1cc are determined by fitting projections of the angular distributions in four intervals of the square of the dimuon invariant mass. arxiv.org/abs/2608.21082

Search for B meson decays to multimuon final states - No signal is found, and upper limits spanning the range of 0.6×10⁻⁹ to 5.4×10⁻⁷ are set on their branching fractions. In addition, limits across the intermediate-particle lifetime ranges considered are determined. arxiv.org/abs/2608.17855

Improved measurement of CP violation in Bₛ⁰→J/ψπ⁺π⁻ decays - The combination with previous measurements yields ϕs=−0.046±0.031rad, |λ|=0.975±0.024 and ΓH=0.610±0.004ps−1, while the combination including all other LHCb measurements gives ϕs=−0.041±0.017rad. arxiv.org/abs/2608.14119

Model-independent measurement of the transversity amplitudes of the B⁰→K*⁰μ⁺μ⁻ decay - Depending on the binning scheme, the deviation of the Wilson coefficient C9 from its Standard Model expectation varies from 4.3σ to 4.8σ. arxiv.org/abs/2608.12215

Study of muon-tagged Dₛ₁(2460)⁺ and Dₛ₁(2536)⁺ decays to the Dₛ⁺π⁺π⁻ final state - The Dalitz-plot distributions of the two decays are found to be different, suggesting differences in the internal structure of the two states, with evidence of exotic contributions. arxiv.org/pdf/2608.10826

New measurements of Bc decays into single charm final states - Five products of branching fraction, B(Bc→DX), and fragmentation ratio fc/fu are reported, Additionally, the CP asymmetry in Bc→D0K decays is measured and found to be compatible with zero. arxiv.org/abs/2608.03453

Final readings of @lhcb.bsky.social papers: we have 7 papers these two weeks. And that's not yet counting the new results that will be shown at ICHEP. #LHCbEditorialBoard

Modification of Υ production in pO and OO collisions at LHCb - The significant suppression in OO data, compared to the small effect in pO data, shows the emergence of additional suppression mechanisms in the relatively small OO collision system. arxiv.org/abs/2608.00182

#LHCbpaper soon on arXiv: Search for CP violation in D⁺ → ϕπ⁺ decays (CERN-EP-2026-158) https://cds.cern.ch/record/2967099

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

Used VELO subdetector on display at Nikhef, after a proven track record at CERN www.nikhef.nl/en/news/used... @cern.bsky.social @lhcb.bsky.social

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

The @lhcb.bsky.social discovers the final missing member of a doubly charmed particle family 💫 The new particle, composed of one strange quark and two charm quarks, completes a set of particles first theorised over half a century ago. Find out more: home.cern/lhcb-discove...

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

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

Observation of the doubly charmed baryon Ωcc+ lhcb-outreach.web.cern.ch/2026/06/03/o...

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

Evidence for the decay Bₛ⁰→ϕη' - The branching ratio relative to the Bₛ⁰→ϕϕ decay is determined to be R=(3.56±0.79±0.18±0.06)×10⁻² arxiv.org/abs/2605.07586

CP violation analysis of local and nonlocal amplitudes in the B⁰→K*⁰μ⁺μ⁻ decay - The precision of the CP-violation observables is improved by an order of magnitude relative to previous measurement. No significant CP violation is observed. arxiv.org/abs/2605.07582

Observation of the chΛb⁰→Λpp̅ - The signal decay is observed with a significance of 5.1 standard deviations. arxiv.org/abs/2605.04348

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

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

Angular analysis of the B⁺→π⁺μ⁺μ⁻ decay - The Standard Model predictions lie within the obtained 68% confidence level interval in the high-mass and within the 99% interval in the low-mass region. arxiv.org/abs/2604.21987

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

Study of the B⁰→Λc⁺Λ̅c⁻Ks⁰ decay - Evidence is found for contributions from two resonant states, Ξc(2923)⁺ and Ξc(2939)⁺, in the Λc⁺Ks⁰ system. arxiv.org/abs/2604.15040

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

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