| 1031. |
- Aaij, R., et al.
(författare)
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Measurement of the Branching Fractions B(B0→p¯pp¯p) and B(B0s→p¯pp¯p)
- 2023
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:9
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Tidskriftsartikel (refereegranskat)abstract
- Searches for the rare hadronic decays B0→p¯pp¯p and B0s→p¯pp¯p are performed using proton-proton collision data recorded by the LHCb experiment and corresponding to an integrated luminosity of 9 fb−1. Significances of 9.3σ and 4.0σ, including statistical and systematic uncertainties, are obtained for the B0→p¯pp¯p and B0s→p¯pp¯p signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays B0→J/ψ(→p¯p)K*0(→K+π−) and B0s→J/ψ(→p¯p)ϕ(→K+K−). The branching fractions are measured to be B(B0→p¯pp¯p)=(2.2±0.4±0.1±0.1)×10−8 and B(B0s→p¯pp¯p)=(2.3±1.0±0.2±0.1)×10−8. In these measurements, the first uncertainty is statistical, the second is systematic, and the third one is due to the external branching fraction of the normalization channel.
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| 1032. |
- Aaij, R., et al.
(författare)
-
Measurement of the charm mixing parameter y(CP)-y(CP)(K pi) using two-body D-0 meson decays
- 2022
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 105:9
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Tidskriftsartikel (refereegranskat)abstract
- A measurement of the ratios of the effective decay widths of D-0 -> pi(-)pi(+) and D-0 -> K- K+ decays over that of D-0 -> K-pi(+) decays is performed with the LHCb experiment using proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb(-1). These observables give access to the charm mixing parameters y(CP)(pi pi) - y(CP)(K pi )and y(CP)(KK) -y(CP)(K pi), and are measured as y(CP)(pi pi) - y(CP)(K pi) = (6.57 +/- 0.53 +/- 0.16) x 10(-3), y(CP)(KK) - y(CP)(K pi) = (7.08 +/- 0.30 +/- 0.14) x 10(-3), where the first uncertainties are statistical and the second systematic. The combination of the two measurements is Y-CP - y(CP)(K pi) = (6.96 +/- 0.26 +/- 0.13) x 10(-3), which is four times more precise than the previous world average.
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| 1033. |
- Aaij, R., et al.
(författare)
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Measurement of the CKM angle γ with B± → D[K∓π±π±π∓] h± decays using a binned phase-space approach
- 2023
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- The CKM angle gamma is determined from CP-violating observables measured in B-+/- -> D[K--/+pi(+/-)pi(+/-)pi(-/+)]h(+/-), (h = K, pi) decays, where the measurements are performed in bins of the decay phase-space of the D meson. Using proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13TeV, corresponding to a total integrated luminosity of 9 fb(-1), gamma is determined to be gamma = (54.8 (+6.0)(-5.8) (+0.6)(-0.6) (+6.7)(-4.3))degrees, where the first uncertainty is statistical, the second systematic and the third from the external inputs on the coherence factors and strong phases of the D-meson decays.
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| 1034. |
- Aaij, R., et al.
(författare)
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Measurement of the CKM angle γ using the B±→†’ D*h± channels
- 2023
-
Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :12
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement of the CP-violating observables from B -> (DK +/-)-K-* and B-+/- -> D-*pi(+/-) decays is presented, where D-*(D) is an admixture of D-*0 and D-0 (D-0 and (0)) states and is reconstructed through the decay chains D-*-> D pi(0)/gamma and D -> KS0 pi+pi-/KS0K+K-. The measurement is performed by analysing the signal yield variation across the D decay phase space and is independent of any amplitude model. The data sample used was collected by the LHCb experiment in proton-proton collisions and corresponds to a total integrated luminosity of 9 fb(-1) at centre-of-mass energies of 7, 8 and 13 TeV. The CKM angle gamma is determined to be (69(-14)(+13))degrees using the measured CP-violating observables. The hadronic parameters r(B)(D)*(K +/-),r(B)(D)*(pi +/-),delta(D)(B)*(K +/-),delta(D)(B)*(pi +/-), which are the ratios and strong phase differences between favoured and suppressed B-+/- decays, are also reported.
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| 1035. |
- Aaij, R., et al.
(författare)
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Measurement of the Λb0 → Λ(1520)Ό+Ό- Differential Branching Fraction
- 2023
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:15
-
Tidskriftsartikel (refereegranskat)abstract
- The branching fraction of the rare decay Lambda(0 )(b)-> Lambda(1520)mu(+)mu(-) is measured for the first time, in the squared dimuon mass intervals q(2), excluding the J/psi and psi(2S) regions. The data sample analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb(-1). The result in the highest q(2) interval, q(2) > 15.0 GeV2/c(4), where theoretical predictions have the smallest model dependence, agrees with the predictions.
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| 1036. |
- Aaij, R., et al.
(författare)
-
Measurement of the Lambda(+)(c) to D-0 production ratio in periphera PbPb collisions at root s(NN)=5.02 TeV
- 2023
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Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479.
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a measurement of the Lambda(+)(c) to D-0 production ratio in peripheral PbPb collisions at root sNN = 5.02TeV with the LHCb detector in the forward rapidity region 2 < y < 4.5. The Lambda(+)(c) (D-0) hadrons are reconstructed via the decay channel Lambda(+)(c) -> pK(-)pi(+) (D-0 -> K- pi(+)) for 2 < pT < 8 GeV/ c and in the centrality range of about 65-90%. The results show no significant dependence on pT, y or the mean number of participating nucleons. They are also consistent with similar measurements obtained by the LHCb collaboration in pPb and Pbp collisions at root sNN = 5.02TeV. The data agree well with predictions from PYTHIA in pp collisions at root s = 5TeV but are in tension with predictions of the Statistical Hadronization model.
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| 1037. |
- Aaij, R., et al.
(författare)
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Measurement of the lifetimes of promptly produced Omega(0)(c) and Xi(9)(c) baryons
- 2022
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Ingår i: Science Bulletin. - : Elsevier. - 2095-9273. ; 67:5, s. 479-487
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Tidskriftsartikel (refereegranskat)abstract
- A measurement of the lifetimes of the Omega(0)(c) and Xi(0)(c) baryons is reported using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb(-1) collected by the LHCb experiment. The Omega(0)(c) and Xi(0)(c) baryons are produced directly from proton interactions and reconstructed in the pK(-)K(-)pi(+) final state. The Omega(0)(c) lifetime is measured to be 276.5 +/- 13.4 +/- 4.4 +/- 0.7 fs, and the Xi(0)(c) lifetime is measured to be 148.0 +/- 2.3 +/- 2.2 +/- 0.2 fs, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the D-0 lifetime. These results confirm previous LHCb measurements based on semileptonic beauty-hadron decays, which disagree with earlier results of a four times shorter Omega(c)0 lifetime, and provide the single most precise measurement of the Omega(0 )(c)lifetime.
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| 1038. |
- Aaij, R., et al.
(författare)
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Measurement of the mass difference and relative production rate of the Ω−b and Ξ−b baryons
- 2023
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 108:5
-
Tidskriftsartikel (refereegranskat)abstract
- The mass difference between the Omega -b and Xi -b baryons is measured using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb-1, and is found to be mo Omega -bthorn - mo Xi -bthorn 1/4 248.54? 0.51ostatthorn ? 0.38osystthorn MeV=c2. The mass of the Omega -b baryon is measured to be mo Omega -bthorn 1/4 6045.9 ? 0.5ostatthorn ? 0.6osystthorn MeV=c2. This is the most precise determination of the Omega -b mass to date. In addition, the production rate of Omega -b baryons relative to that of Xi -b baryons is measured for the first time in pp collisions, using an LHCb dataset collected at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 6 fb-1. Reconstructing beauty baryons in the kinematic region 2 < < 6 and pT < 20 GeV=c with their decays to a J=psi meson and a hyperon, the ratio f Omega- b f Xi- b tation fractions of b quarks into Omega -b and Xi -b baryons, respectively, and B represents the branching fractions of their respective decays.
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| 1039. |
- Aaij, R., et al.
(författare)
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Measurement of the Nuclear Modification Factor and Prompt Charged Particle Production in p-Pb and pp Collisions at root s(NN )=5 TeV
- 2022
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 128:14
-
Tidskriftsartikel (refereegranskat)abstract
- 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
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| 1040. |
- Aaij, R., et al.
(författare)
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Measurement of the photon polarization in Λ0b→Λγ decays
- 2022
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Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 105:5
-
Tidskriftsartikel (refereegranskat)abstract
- The photon polarization in b -> s gamma transitions is measured for the first time in radiative b -baryon decays exploiting the unique spin structure of Lambda(0)(b)-> Lambda(gamma) decays. A data sample corresponding to an integrated luminosity of 6 fb(-1) collected by the LHCb experiment in pp collisions at a center-of-mass energy of 13 TeV is used. The photon polarization is measured to be alpha(gamma) = 0.82(-0.26-0.)(13)(+)(0.17+0.04), where the first uncertainty is statistical and the second systematic. This result is in agreement with the Standard Model prediction and previous measurements in b-meson decays. Charge-parity breaking effects are studied for the first time in this observable and found to be consistent with CP symmetry.
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