LHCb physics

The forward experiment at the LHC. We tweet physics results. CC BY 4.0. Managed by @pkoppenburg.

2023-05-03

Test of lepton flavour universality using B⁰ → D*⁻τ⁺ν decays with hadronic τ channels arxiv.org/abs/2305.01463 - The lepton universality test R(D*⁻)≡B(B⁰ → D*⁻τ⁺ν)/B(B⁰ → D*⁻μ+ν) is calculated as 0.247±0.015±0.015±0.012.

2023-05-01

Study of charmonium decays to K⁰s Kπ in the B → (K⁰sKπ)K channels arxiv.org/abs/2304.14891 - New precise measurements of the ηc and ηc(2S) resonance parameters are performed. The first observation and branching fraction measurement of B+→χc0K0π+ is reported.

2023-04-05

D*(2007)⁰→μ⁺μ⁻ in B⁻→π⁻μ⁺μ⁻ decays arxiv.org/abs/2304.01981 - This is the first limit on the branching fraction of D*(2007)⁰→μ⁺μ⁻ and the first search for a rare charm-meson decay exploiting production via beauty decays.

2023-03-17

Observation of the B⁺→J/ψη′K⁺ decay arxiv.org/abs/2303.09443 - The branching fraction of this decay is measured relative to the known branching fraction of the B⁺→ψ(2S)K⁺ decays and found to be (4.91±0.47±0.29±0.07)×10⁻².

Mass distributions from the paper
2023-03-08

Search for CP violation in D⁺ and Ds⁺→K⁻K⁺K⁺ decays. The results are given as p-values for the hypothesis of CP conservation and are found to be 13.3% for the Ds⁺→K⁻K⁺K⁺ decay and 31.6% for the D⁺→K⁻K⁺K⁺ decay.

Asymmetries in Dalitz plots
2023-02-22

Observation of the Bₛ⁰→χc1(3872)π⁺π⁻ decay arxiv.org/abs/2302.10629 - The first observation is reported. The mass spectrum of the π⁺π⁻ system recoiling against the χc1(3872) meson exhibits a large contribution from f₀ mesons.

2023-02-17

Measurement of the Λb⁰→Λ(1520)μ⁺μ⁻ differential branching fraction arxiv.org/abs/2302.08262 - The result in the highest q² interval, q²>15.0 GeV², where theoretical predictions have the smallest model dependence, agrees with the predictions.

2023-02-17

Measurement of the Λb⁰→Λ(1520)μ⁺μ⁻ differential branching fraction arxiv.org/abs/2302.08262 - The result in the highest q² interval, q²>15.0 GeV², where theoretical predictions have the smallest model dependence, agrees with the predictions.

2023-02-10

Observation of new Ωc⁰ states decaying to the Ξc⁺K⁻ final state arxiv.org/abs/2302.04733 - Two new excited states, Ωc(3185) and Ωc(3327), are observed

2023-02-08

Measurement of the ratios of branching fractions R(D∗) and R(D⁰) arxiv.org/abs/2302.02886 - The ratios of branching fractions B(B̅→D*τ⁻ν̅)/B(B̅→D*μ⁻ν̅) and B(B̅→D⁰τ⁻ν̅)/B(B̅→D⁰μ⁻ν̅) are measured as 0.281±0.018±0.024 and 0.441±0.060±0.066, respectively.

2023-01-27

A study of CP violation in the decays B⁺→[K⁺K⁻π⁺π⁻]_D h⁺ (h = K, π) and B⁺→[π⁺π⁻π⁺π⁻]_D h⁺ arxiv.org/abs/2301.10328 - The analysis is performed in bins of phase space. The angle γ of the Unitarity Triangle are determined.

2023-01-26

A study of CP violation in the decays B⁺→[K⁺K⁻π⁺π⁻]_D h⁺ (h = K, π) and B⁺→[π⁺π⁻π⁺π⁻]_D h⁺ arxiv.org/abs/2301.10328 - The analysis is performed in bins of phase space, which are optimised for sensitivity to local CP asymmetries. The angle γ of the Unitarity Triangle are determined.

2023-01-18

Λc⁺ polarimetry using the dominant hadronic mode arxiv.org/abs/2301.07010 - Using a recent amplitude analysis of the Λ+c→pK−π+ decay performed at the LHCb experiment, we compute the distribution of the kinematic-dependent polarimeter vector.

2023-01-13

Evidence of a J/ψKs⁰ structure in B⁰→J/ψϕKs⁰ decays arxiv.org/abs/2301.04899 - Evidence of a J/ψKs⁰ structure is seen. The state is likely to be the isospin partner of a state previously observed in the J/ψK⁺ system of the B⁺→J/ψϕK⁺ decay.

J/psiK mass fits in charged and neutral mode.
2022-12-27

Measurement of Υ production in pp collisions at √s=5 TeV arxiv.org/abs/2212.12664 - Double differential cross-sections times branching fractions, as functions of the transverse momentum and the rapidity y of the Υ mesons, are measured in the range pT<20 GeV/c and 2.0<y<4.5.

Cross-sections of Y(1S) vs pt.Total cross-sections versus energy.
2022-12-22

Search for rare decays of D⁰ mesons into two muons arxiv.org/abs/2212.11203 - An upper limit on the branching fraction of this decay is set at B(D⁰→μ⁺μ⁻)<3.1× 10⁻⁹ at a 90% CL, the world's most stringent limit.

Mass distributions from the paper.
2022-12-20

Test of lepton universality in b→sℓ⁺ℓ⁻ decays arxiv.org/abs/2212.09152 - Each of the four lepton universality measurements reported is either the first or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

2022-12-20

Test of lepton universality in b→sℓ⁺ℓ⁻ decays arxiv.org/abs/2212.09152 arxiv.org/abs/2212.09153 - Each of the four lepton universality measurements reported is either the first or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

2022-12-20

Today seminar on "Measurements of 𝑅(𝐾) and 𝑅(𝐾∗) with the full LHCb Run 1 and 2 data" at 11h CET with webcast indico.cern.ch/event/1187945/

2022-12-20

Today seminar by @QuaglianiRenato@twitter.com "Measurements of 𝑅(𝐾) and 𝑅(𝐾∗) with the full LHCb Run 1 and 2 data" at 11h CET with webcast indico.cern.ch/event/1187945/

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