The first study of the angular distribution of μ+μ− pairs produced in the forward rapidity region via the Drell-Yan reaction pp→γ*/Z+X→ℓ+ℓ−+X is presented, using data collected with the LHCb detector at a center-...
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The first study of the angular distribution of μ+μ− pairs produced in the forward rapidity region via the Drell-Yan reaction pp→γ*/Z+X→ℓ+ℓ−+X is presented, using data collected with the LHCb detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.1 fb−1. The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the Z-boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton.
The first observation of the semileptonic b-baryon decay Λb0→Λc+τ−ν¯τ, with a significance of 6.1σ, is reported using a data sample corresponding to 3 fb−1 of integrated luminosity, collected by the LHCb ...
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The first observation of the semileptonic b-baryon decay Λb0→Λc+τ−ν¯τ, with a significance of 6.1σ, is reported using a data sample corresponding to 3 fb−1 of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ− lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λb0→Λc+τ−ν¯τ)/B(Λb0→Λc+π−π+π−) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λb0→Λc+τ−ν¯τ)=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λb0→Λc+π−π+π−. The ratio of semileptonic branching fractions R(Λc+)≡B(Λb0→Λc+τ−ν¯τ)/B(Λb0→Λc+μ−ν¯μ) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λb0→Λc+μ−ν¯μ contributes to the last term. This result is in agreement with the standard model prediction.
We present the Dark Energy Spectroscopic Instrument (DESI) Strong Lens Foundry. We discovered ∼ 3500 new strong gravitational lens candidates in the DESI Legacy Imaging Surveys using residual neural networks (ResNet)...
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Two narrow resonant states are observed in the Λb0K−π+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an int...
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Two narrow resonant states are observed in the Λb0K−π+ mass spectrum using a data sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the LHCb experiment and corresponding to an integrated luminosity of 6 fb−1. The minimal quark content of the Λb0K−π+ system indicates that these are excited Ξb0 baryons. The masses of the Ξb(6327)0 and Ξb(6333)0 states are m[Ξb(6327)0]=6327.28−0.21+0.23±0.12±0.24 and m[Ξb(6333)0]=6332.69−0.18+0.17±0.03±0.22 MeV, respectively, with a mass splitting of Δm=5.41−0.27+0.26±0.12 MeV, where the uncertainties are statistical, systematic, and due to the Λb0 mass measurement. The measured natural widths of these states are consistent with zero, with upper limits of Γ[Ξb(6327)0]<2.20(2.56) and Γ[Ξb(6333)0]<1.60(1.92) MeV at a 90% (95%) credibility level. The significance of the two-peak hypothesis is larger than nine (five) Gaussian standard deviations compared to the no-peak (one-peak) hypothesis. The masses, widths, and resonant structure of the new states are in good agreement with the expectations for a doublet of 1D Ξb0 resonances.
Tests of lepton universality in B0→KS0ℓ+ℓ− and B+→K*+ℓ+ℓ− decays where ℓ is either an electron or a muon are presented. The differential branching fractions of B0→KS0e+e− and B+→K*+e+e− decays are measured in inte...
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Tests of lepton universality in B0→KS0ℓ+ℓ− and B+→K*+ℓ+ℓ− decays where ℓ is either an electron or a muon are presented. The differential branching fractions of B0→KS0e+e− and B+→K*+e+e− decays are measured in intervals of the dilepton invariant mass squared. The measurements are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1 . The results are consistent with the standard model and previous tests of lepton universality in related decay modes. The first observation of B0→KS0e+e− and B+→K*+e+e− decays is reported.
Events containing a Z boson and a charm jet are studied for the first time in the forward region of proton-proton collisions. The data sample used corresponds to an integrated luminosity of 6 fb−1 collected at a cent...
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Events containing a Z boson and a charm jet are studied for the first time in the forward region of proton-proton collisions. The data sample used corresponds to an integrated luminosity of 6 fb−1 collected at a center-of-mass energy of 13 TeV with the LHCb detector. In events with a Z boson and a jet, the fraction of charm jets is determined in intervals of Z-boson rapidity in the range 2.0
The first full angular analysis and an updated measurement of the decay-rate CP asymmetry of the D0→π+π−μ+μ− and D0→K+K−μ+μ− decays are reported. The analysis uses proton-proton collision data collected with t...
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The first full angular analysis and an updated measurement of the decay-rate CP asymmetry of the D0→π+π−μ+μ− and D0→K+K−μ+μ− decays are reported. The analysis uses proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. The dataset corresponds to an integrated luminosity of 9 fb−1. The full set of CP -averaged angular observables and their CP asymmetries are measured as a function of the dimuon invariant mass. The results are consistent with expectations from the standard model and with CP symmetry.
The production of prompt charged particles in proton-lead collisions and in proton-proton collisions at the nucleon-nucleon center-of-mass energy sNN=5 TeV is studied at LHCb as a function of pseudorapidity (η) and ...
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The production of prompt charged particles in proton-lead collisions and in proton-proton collisions at the nucleon-nucleon center-of-mass energy sNN=5 TeV is studied at LHCb as a function of pseudorapidity (η) and transverse momentum (pT) with respect to the proton beam direction. The nuclear modification factor for charged particles is determined as a function of η between −4.8<η<−2.5 (backward region) and 2.0<η<4.8 (forward region), and pT between 0.2
Branching fraction and effective lifetime measurements of the rare decay Bs0→μ+μ− and searches for the decays B0→μ+μ− and Bs0→μ+μ−γ are reported using proton-proton collision data collected with the LHCb det...
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Branching fraction and effective lifetime measurements of the rare decay Bs0→μ+μ− and searches for the decays B0→μ+μ− and Bs0→μ+μ−γ are reported using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a luminosity of 9 fb−1. The branching fraction B(Bs0→μ+μ−)=(3.09−0.43−0.11+0.46+0.15)×10−9 and the effective lifetime τ(Bs0→μ+μ−)=2.07±0.29±0.03 ps are measured, where the first uncertainty is statistical and the second systematic. No significant signal for B0→μ+μ− and Bs0→μ+μ−γ decays is found and upper limits B(B0→μ+μ−)<2.6×10−10 and B(Bs0→μ+μ−γ)<2.0×10−9 at the 95% C.L. are determined, where the latter is limited to the range mμμ>4.9 GeV/c2. The results are in agreement with the standard model expectations.
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