LHCb Experiment

#LHCbpaper soon on arXiv: Polarization measurement of Λ⁺_c and Λ⁻_c baryons in pNe collisions at √(s_NN) = 68.6 GeV (CERN-EP-2026-016) https://cds.cern.ch/record/2954975

Search for τ⁻→μ⁻μ⁻μ⁺ decays at the LHCb experiment with Run 2 data arxiv.org/abs/2601.20785 - An upper limit of 1.9(2.3)×10⁻⁸ is set at the 90% (95%) confidence level on the branching fraction of the decay.

Observation of the decay χc₁(3872)→J/ψμ⁺μ⁻ arxiv.org/abs/2601.20790 - Its branching fraction is measured relative to the χc1(3872)→J/ψπ⁺π⁻ decay mode as (1.64±0.32±0.05)×10⁻³.

Machine learning techniques for jet reconstruction at LHCb and application to the search for H→bb̅ and H→cc̅ in √s=13 TeV pp collisions arxiv.org/abs/2601.16802 - The observed (expected) 95% confidence level upper limits correspond to 6.6 (11.1), and 1003 (1834) times the SM, respectively.

Observation of CP violation in B⁰→J/ψρ(770)⁰ decays arxiv.org/abs/2601.15646 - The CP-violation parameters for this process are determined to be 2β=0.710±0.084±0.028 rad and |λ|=1.019±0.034±0.009, where the first uncertainty is statistical and the second systematic.

Evidence for the rare decay B⁺→Λ̅pμ⁺μ⁻ arxiv.org/abs/2601.06878 - In the low invariant-mass region of m(Λ̅p)<2.8 GeV, the branching fraction is measured to be (1.70+0.65−0.56(stat)±0.17(syst)±0.14(ext))×10⁻⁸.

Search for lepton-number-violating B⁻→D⁽*⁾⁺μ⁻μ⁻ decays arxiv.org/abs/2601.07657 - No significant signal is observed, and upper limits are set on the branching fractions, B(B⁻→D⁺μ⁻μ⁻)<4.6×10⁻⁸ and B(B⁻→D*⁺μ⁻μ⁻)<5.9×10⁻⁸, at the 95% confidence level.

First evidence of the Bₛ⁰→K⁻π⁺γ decay arxiv.org/abs/2601.03083 - The photons are reconstructed through their conversion into an electron-positron pair, which significantly improves the mass resolution. A signal excess with a significance of 3.5 standard deviations is measured.

🎄A comprehensive analysis of the B⁰→ K*⁰μ⁺μ⁻ decay arxiv.org/abs/2512.18053 - The measurements of the CP-averaged observables and the branching fractions continue to exhibit the pattern of tensions with the Standard Model predictions that have been seen in previous analyses.

Search for heavy neutral leptons in B-meson decays arxiv.org/abs/2512.14551 - The results are interpreted in both lepton-number-conserving and lepton-number-violating scenarios. No significant excess is observed. Constraints are placed on the mixing element |UμN| to the active muon neutrino.

Measurement of the top-quark production cross-section and charge asymmetry at LHCb arxiv.org/abs/2512.11324 - The cross-sections for the top and antitop quarks are σt=0.95±0.04±0.08±0.02 pb, σt¯=0.81±0.03±0.07±0.02 pb.. The top-quark charge asymmetry is measured to be AtC=0.08±0.03±0.01.

Precision measurement of CP violation and branching fractions in B⁺→Ksh⁺ (h=π,K) decays and search for the rare decay Bc⁺→KsK⁺ arxiv.org/abs/2512.09288 - The branching-fraction ratio is measured to be B(B⁺→KsK⁺)/B(B⁺→Ksπ⁺)=0.055±0.004±0.002.

Measurement of the branching fractions and longitudinal polarisations of B₍ₛ₎⁰→K*⁰K̅*⁰ decays arxiv.org/abs/2512.05102 - The theory-motivated L(K*K̅*) observable is found to be 4.92 ± 0.55 ± 0.47 ± 0.02 ± 0.10, 4.4σ away from the SM prediction.

Observation and investigation of the Tcc̅1(4430)⁺ structure in B⁺→ψ(2S)Ks⁰π⁺ decays arxiv.org/abs/2511.20428 - The properties of the Tcc̅1(4430)⁺ structure are consistent with the exotic state reported in the isospin-related B̅⁰→ψ(2S)K⁻π⁺ decay.

First observation of the Bₛ⁰→Λc⁺Λ̅c⁻ decay and evidence for the B⁰→Λc⁺Λ̅c⁻ decay arxiv.org/abs/2511.20476 - The branching fractions are measured to be (1.01+0.27−0.28±0.08±0.15)×10⁻⁵ and (5.0±1.3±0.5±0.8)×10⁻⁵.

YouTube video by CERN Quark-gluon plasma Explained - Ep. 1/2

Here are the first event displays from @atlasexperiment.bsky.social @cmsexperiment.bsky.social the ALICE Experiment and @lhcb.bsky.social recorded last Friday.

Discover more about quark-gluon plasma: www.youtube.com/watch?v=mBfJ...

Differential decay rate of B⁺→J/ψK⁺ with the LHCb Upgrade I experiment arxiv.org/abs/2511.16564 - The normalised decay rate is measured using a data sample corresponding to an integrated luminosity of 1.1fb−1 collected during October 2024 with the upgraded (Upgrade I) LHCb detector.

Branching fraction measurement of the Λ→pμν decay arxiv.org/abs/2511.15681 - This result improves the precision of the branching fraction measurement by a factor of two compared to the previous best measurement and sets a more stringent bound on lepton flavour universality in s→u quark transitions.

Measurement of charged-hadron distributions in heavy-flavor jets in proton-proton collisions at √s=13 TeV arxiv.org/abs/2511.10216 - The observed differences between the heavy- and light-jet distributions are consistent with the heavy-quark dynamics expected to arise from the dead-cone effect [...].

Search for K⁰→π⁺π⁻μ⁺μ⁻ decays at LHCb arxiv.org/abs/2511.02619 - Upper limits are set for the first time on the branching fractions B(K⁰s→π⁺π⁻μ⁺μ⁻)<1.4×10⁻⁹ and B(K⁰L→π⁺π⁻μ⁺μ⁻)<6.6×10⁻⁷, at the 90% confidence level.

For the first time LHCb recorded 10/fb pp collisions in a single year.
The legacy detector which we upgraded in 2018-21 collected a total of 9/fb between 2010 and 2018.

Measurement of CP asymmetry in D⁰→KsKs decays with the LHCb Upgrade I detector arxiv.org/abs/2510.14732 - A measurement of CP asymmetry in D⁰→KsKs decays is reported using 6.2/fb recorded with the LHCb Upgrade I detector. This is the most precise determination of this quantity to date.

Searches for B⁰→K⁺π⁻τ⁺τ⁻ and Bₛ⁰→K⁺K⁻τ⁺τ⁻ decays arxiv.org/abs/2510.13716 - This is he first limit for the Bₛ⁰→K⁺K⁻τ⁺τ⁻ decay. For the decay B⁰→K*(892)⁰τ⁺τ⁻, this result improves on the current best upper limit by an order of magnitude.

Study of charm mixing and CP violation with D⁰→K⁺π⁻π⁺π⁻ decays arxiv.org/abs/2510.04963 - It is found that x=(0.85+0.15−0.24)%, y=(0.21+0.29−0.27)%, Δx=(−0.02±0.04)% and Δy=(0.02+0.04−0.03)%. These results are consistent with previous measurements and the hypothesis of CP conservation.

Measurement of the W→μν cross-sections as a function of the muon transverse momentum in pp collisions at 5.02 TeV arxiv.org/abs/2509.18817 - This analysis introduces a new method to determine the W-boson mass using the measured differential cross-sections corrected for detector effects.

This is the 800th LHCb paper. 🎉

Observation of Bc⁺→D⁺h⁺h⁻decays arxiv.org/abs/2509.15873 - The decays Bc⁺→D⁺K⁺π⁻, Bc⁺→D*⁺K⁺π⁻ and Bc⁺→Dₛ⁺K⁺K⁻ are observed for the first time.

First evidence of CP violation in beauty baryon to charmonium decays arxiv.org/abs/2509.16103 - The difference in the CP asymmetries between Λ⁰b→J/ψpπ⁻ and Λ⁰b→J/ψKπ⁻ decays is measured to be ΔACP=(4.0±1.2±0.2)%.

A model-independent measurement of the CKM angle γ in the decays B⁺→[K⁺K⁻π⁺π⁻]h⁺ and B⁺→[π⁺π⁻π⁺π⁻]h⁺ (h=K,π) arxiv.org/abs/2509.15139 - The result of this binned analysis is γ=(53.9+9.5−8.9)∘, where the uncertainty includes both statistical and systematic contributions.

Measurement of the branching fraction of the Λb⁰→J/ψΛ decay and isospin asymmetry of B→J/ψK decays arxiv.org/abs/2509.12805 - B(Λb⁰→J/ψΛ)=(3.34±0.02±0.10±0.08±0.28)×10−4. In addition, the isospin asymmetry between the rates of B⁰→J/ψK⁰s and B⁺→J/ψK+ decays is measured to be AI=−0.0135±0.0004±0.0133.