LHCb Experiment
@lhcb.bsky.social
📤 1280
📥 12
📝 138
The LHCb experiment at CERN. cern.ch/lhcb-public.
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.
6 days ago
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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.
25 days ago
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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.
25 days ago
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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.
26 days ago
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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.
about 1 month ago
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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.
about 2 months ago
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This is the 800th LHCb paper. 🎉
add a skeleton here at some point
about 2 months ago
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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.
about 2 months ago
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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)%.
about 2 months ago
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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.
about 2 months ago
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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.
about 2 months ago
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Amplitude analysis of B⁰→ηc(1S)K⁺π⁻ decays
arxiv.org/abs/2509.03133
- The data are described with a model including only intermediate contributions from known K*⁰ resonances. Evidence for an exotic resonance in the ηcπ⁻ system, reported in a previous analysis of this decay channel, is not confirmed.
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2 months ago
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Inclusive B-meson flavour-tagging algorithm at LHCb
arxiv.org/abs/2508.20180
- This new algorithm improves the tagging power by 35% for B0 mesons and 20% for B0s mesons when compared to the combined performance of the existing LHCb flavour-tagging algorithms.
2 months ago
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Measurement of branching fractions and CP asymmetries in Λb⁰(Ξb⁰)→pKs⁰h⁻ decays
arxiv.org/abs/2508.17836
- The decays Λb⁰ and Ξb⁰→pKs⁰K⁻ are observed for the first time. No evidence of CP violation is observed.
3 months ago
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First observation of the charmless baryonic decay B⁺→Λ̅pp̅p
arxiv.org/abs/2508.16259
- The branching fraction for this decay is measured for the first time, as (2.08±0.34±0.12±0.26)×10⁻⁷. The mass distributions of Λ̅p and p̅p pairs exhibit pronounced enhancements at both kinematic thresholds.
3 months ago
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First observation of CP violation and measurement of polarization in B⁺→ρ(770)⁰K*(892)⁺ decays
arxiv.org/abs/2508.13563
- The CP asymmetry is measured to be 0.507±0.062)±0.017 and the CP-averaged longitudinal polarization fraction 0.720±0.028±0.009.
3 months ago
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Deuteron identification via time of flight with LHCb
arxiv.org/abs/2508.06305
- The timing capabilities of the LHCb detector operated during the LHC Run 2 can be used to identify light ion particles with momenta of a few GeV/c.
3 months ago
1
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1
reposted by
LHCb Experiment
LHCb Results
3 months ago
#LHCbpaper: Measurement of transverse Λ and Λ̅ hyperon polarisation in pPb collisions at √(s_NN) = 5.02 TeV (arXiv:2508.02009)
https://arxiv.org/abs/2508.02009
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reposted by
LHCb Experiment
LHCb Results
3 months ago
#LHCbpaper: Amplitude analysis of the Ξ⁺_c → pK⁻π⁺ decay and Ξ⁺_c baryon polarization measurement in semileptonic beauty-hadron decays (arXiv:2508.00492)
https://arxiv.org/abs/2508.00492
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Search for the decay B⁰→ϕϕ
arxiv.org/abs/2507.20945
- No significant signal is observed, and an upper limit on the branching fraction of 1.3 (1.4)×10⁻⁸ at 90 (95)% confidence level is set.
3 months ago
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Search for resonances decaying to photon pairs with masses between 4.9 and 19.4 GeV
arxiv.org/abs/2507.14390
- Upper limits on the photon-pair branching fraction times the cross-section of ALP production are determined, as well as B(Bs⁰→γγ)<2.7×10⁻⁵, B(B⁰→γγ)<0.83×10⁻⁵ and σ(pp→ηbX)×B(ηb→γγ)<765pb.
4 months ago
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Measurement of the B⁰→ρ(770)⁰γ branching fraction
arxiv.org/abs/2507.14401
- The branching fraction for is obtained as (7.9±0.3±0.2±0.2)×10⁻⁷. It is consistent with the current world-average value and by far the most precise measurement to date.
4 months ago
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Improved measurement of η/η′ mixing in B⁰ and Bs⁰→J/ψη⁽'⁾decays
arxiv.org/abs/2507.13914
- The angle ϕG differs from zero by more than four standard deviations, which points to a substantial glueball component and/or unexpectedly large contributions from gluon-mediated processes in these decays.
4 months ago
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reposted by
LHCb Experiment
LHCb Results
4 months ago
#LHCbpaper: Precision measurement of the Ξ⁰_b baryon lifetime (arXiv:2507.12402)
https://arxiv.org/abs/2507.12402
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reposted by
LHCb Experiment
LHCb Results
4 months ago
#LHCbpaper: First observation of the Λ⁰_b → Λ⁺_c D⁻_s K⁺K⁻ decay and search for pentaquarks in the Λ⁺_c D⁻_s system (arXiv:2507.10713)
https://arxiv.org/abs/2507.10713
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Observation of orbitally excited Bc⁺ states
arxiv.org/abs/2507.02149
- The observation of a wide peaking structure in the B+cγ mass spectrum is reported and well described by an effective minimal model consisting of two narrow peaks located at 6704.8±5.5±2.8±0.3 MeV and 6752.4±9.5±3.1±0.3 MeV.
4 months ago
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Updated measurement of CP violation and polarisation in B⁰s→J/ψK̅*(892)⁰ decays
arxiv.org/abs/2506.22090
- The longitudinal and parallel polarisation fractions are determined to be f₀=0.534±0.012±0.009 and f∥=0.211±0.014±0.005, providing the most precise values for these observables to date.
4 months ago
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reposted by
LHCb Experiment
CERN
5 months ago
New hadrons spotted in the wild for the first time 🔍 A class of orbitally–excited bound states of charm and beauty quark-antiquark pairs were recently observed by the
#LHCbexperiment
for the first time ever.
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Welcome to the
@lhcbpapers.bsky.social
🤖. Thanks to
@clelange.bsky.social
for creating it.
add a skeleton here at some point
5 months ago
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Search for the lepton-flavour-violating decays B⁰→K*⁰τ⁺e⁻
arxiv.org/abs/2506.15347
- No significant signal is observed, and upper limits on the branching fractions are determined to be B(B⁰→K*⁰τ⁻e⁺)<5.9 (7.1)×10⁻⁶ and B(B⁰→K*⁰τ⁺e⁻)<4.9 (5.9)×10⁻⁶ at the 90% (95%) confidence level.
5 months ago
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reposted by
LHCb Experiment
CNRS Nucléaire & Particules
5 months ago
#TalentsCNRS | Michaël Winn, physicien hadronique à l'Irfu du CEA, reçoit la médaille de bronze du @cnrs.fr 👏 « Dans un champ qui mêle plusieurs branches de la physique, j’essaie de répondre aux questions les plus simples. » 🔗
www.in2p3.cnrs.fr/fr...
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Measurement of the Ωc⁰ and Ξc⁰ baryon lifetimes using hadronic b-baryon decays
arxiv.org/abs/2506.13334
- The charm baryons are produced in the fully reconstructed decay chains of b baryons. The results are consistent with previous measurements performed by the LHCb experiment.
5 months ago
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Coherent photoproduction of ρ⁰,ω and excited vector mesons in ultraperipheral PbPb collisions
arxiv.org/abs/2506.06250
- The dominant contribution is due to the ρ⁰ meson but a consistent description requires accounting for the ω meson and two resonances at 1350±20 MeV and 1790±20 MeV.
5 months ago
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Three-pion Bose-Einstein correlations measured in proton-proton collisions
arxiv.org/abs/2506.03072
- This measurement provides insight into the nature of hadronisation in terms of coherence, showing a coherent emission of pions.
5 months ago
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Measurement of the Lund plane for light- and beauty-quark jets
arxiv.org/abs/2505.23530
- First measurement of the LJP for light-quark-enriched and beauty-initiated jets at 13 TeV at LHCb and first direct observation of the dead-cone effect in beauty-quark jets in the collinear region of the LJP.
5 months ago
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Measurement of the Z-boson mass
arxiv.org/abs/2505.15582
- The first dedicated Z-boson mass measurement at the LHC with Z → μ+μ− decays is reported. The dataset uses proton-proton collisions at a centre-of-mass energy of 13 TeV, recorded in 2016. A template fit yields 91184.2±8.5±3.8MeV.
6 months ago
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Measurements of charmed meson and antimeson production asymmetries at √s=13.6 TeV
arxiv.org/abs/2505.14494
- These measurements constitute the first measurements of production asymmetries at this centre-of-mass energy of colliding beams, and the first measurements with the LHCb Run 3 detector.
6 months ago
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First measurement of b-jet mass with and without grooming
arxiv.org/abs/2505.11955
- Measurements of the jet mass for jets containing fully reconstructed B hadrons are reported with and without grooming. These results offer unparalleled tests of quark flavour and mass dependence in QCD.
6 months ago
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Measurement of the branching fraction ratio Rk at large dilepton invariant mass
arxiv.org/abs/2505.03483
- A test of lepton universality between muons and electrons using B⁺→K⁺ℓ⁺ℓ⁻ decays with the dilepton invariant-mass-squared region above 14.3 GeV²/c⁴ is consistent with the prediction of unity.
6 months ago
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Observation of the decay Bₛ⁰→K⁰pp̅ and measurement of the B₍ₛ₎⁰→K⁰pp̅ branching fractions
arxiv.org/abs/2504.21269
- The decay Bₛ⁰→K⁰pp̅ is observed for the first time, with a measured branching fraction of (9.14±1.69±0.90±0.33±0.20)×10⁻⁷ and a significance of 5.6σ.
6 months ago
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Angular analysis of the decay Bₛ⁰→ϕe⁺e⁻
arxiv.org/abs/2504.06346
- Observables are determined in three bins of dielectron mass squared, q², corresponding to [0.1,1.1], [1.1,6.0] and [15.0,19.0] GeV². The results are compatible with predictions based on the Standard Model of particle physics.
7 months ago
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Observation of the very rare Σ⁺→pμ⁺μ⁻ decay
arxiv.org/abs/2504.06096
- A yield of 237±16 decays is obtained. A branching fraction of (1.08±0.17)×10⁻⁸ is measured. This represents the rarest decay of a baryon ever observed.
7 months ago
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Observation of the doubly-charmed-baryon decay Ξcc⁺→Ξ⁰π⁺π⁺
arxiv.org/abs/2504.05063
- Using the Ξcc⁺→Λ⁺cK⁻π⁺π⁺ decay as the normalisation channel, the branching fraction ratio is measured to be 0.105±0.014±0.007.
7 months ago
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The LHCb collaboration has been awarded the 2025 breakthrough prize in Fundamental Physics, along with
#ALICE
,
@atlasexperiment.bsky.social
and
@cmsexperiment.bsky.social
. The prize has been awarded to all current and former members who have authored Run-2 data papers by 15 July 2024. .
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The 2025 Breakthrough Prize in Fundamental Physics awarded to the LHCb collaboration
https://lhcb-outreach.web.cern.ch/2025/04/07/the-2025-breakthrough-prize-in-fundamental-physics-awarded-to-the-lhcb-collaboration/
7 months ago
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reposted by
LHCb Experiment
CERN
7 months ago
Piecing the matter–antimatter puzzle together 🧩 Last week, the
@lhcb.bsky.social
announced the observation of CP violation in baryons.
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Computing and software for LHCb Upgrade II
arxiv.org/abs/2503.24106
- The second major upgrade will experience extremely high particle fluences and data rates, posing a high challenge for the software and computing resources needed to readout, reconstruct, select and analyse the data.
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Computing and software for LHCb Upgrade II
A second major upgrade of the LHCb experiment is necessary to allow full exploitation of the High Luminosity LHC for flavour physics. The new experiment will operate in Run 5 of the LHC at a luminosit...
https://arxiv.org/abs/2503.24106
7 months ago
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Heavy ion physics with LHCb Upgrade II
arxiv.org/abs/2503.23093
- A second major LHCb detector upgrade will be installed during long shutdown 4. The new detector will provide excellent performance for studies of QCD at high temperature and density, as achieved in collisions of heavy nuclei.
7 months ago
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Discovery potential of LHCb Upgrade II
arxiv.org/abs/2503.23087
- A second major upgrade of the LHCb detector is necessary to allow full exploitation of the HL-LHC for flavour physics.
7 months ago
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Projections for Key Measurements in Heavy Flavour Physics
arxiv.org/abs/2503.24346
- There are excellent prospects for significantly improved measurements in heavy flavour physics, with upgrades in progress or planned for the ATLAS, CMS and LHCb experiments, and for the Belle II experiment.
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Projections for Key Measurements in Heavy Flavour Physics
Precision studies of flavour-changing processes involving quarks and leptons provide a number of ways to improve knowledge of the Standard Model and search for physics beyond it. There are excellent s...
https://arxiv.org/abs/2503.24346
7 months ago
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Search for the Bc⁺→χc1(3872)π⁺ decay
arxiv.org/abs/2503.20039
- No large enhancement is observed, which supports neither the conclusions drawn by the ATLAS collaboration, nor expectations from the compact-tetraquark interpretation of the χc1(3872) state.
8 months ago
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