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1.	Carlsson, Christer, et al. (författare) Consensus in distributed soft environments 1992 Ingår i: European Journal of Operational Research. - : Elsevier. - 0377-2217 .- 1872-6860. ; 61:1-2, s. 165-185 Tidskriftsartikel (refereegranskat)abstract This paper studies the problem of formalizing consensus reaching within a set of decision makers trying to find and agree upon a mutual decision. Decision makers produce their individual rankings, using their own pet decision schemas. Thus consensus reaching relies only on the aggregation of individual decisions rather than on individual decision procedures. The aggregation of the individual rankings is supported by an advising monitor which tries to contract the decision makers into a mutual decision through soft enforcement. Convergence to consensus then depends upon the decision makers' willingness to compromise. We use a topological approach to consensus where we can measure distances between decision makers. Within the approach we can also model the trade-off between a degree of consensus and a strength of majority.
2.	Eklund, Heidi-Tuulia, et al. (författare) A comparative framework for assessment in education and health 2023 Ingår i: Global perspectives on health assessments for an aging population. - : IGI Global. - 9781668476314 - 9781668476307 ; , s. 1-12 Bokkapitel (refereegranskat)abstract In this chapter the authors compare assessment techniques in education and health. These examples are drawn from assessment for learning in secondary school as compared with assessment of functioning in care of older people. Content in these respective assessment environments is obviously quite different, but there is some overlap, in particular related to social circumstances. The authors further argue that the assessment structure and formal analysis techniques are and even should be quite similar. These two domains of assessments share not only a common information and terminological structure, but also a common assessment framework (CAF) which is shown to be extendable by process detail. In this focus on assessment in health, particularly in active and healthy ageing, the model is intended to support the integration of information and processes (decision and intervention pathways) supporting various types of providers.
3.	Eklund, Heidi-Tuulia, et al. (författare) Logic and process drama 2013 Konferensbidrag (refereegranskat)
4.	Eklund, Heidi-Tuulia, et al. (författare) Process drama based information management for assessment and classification in learning 2014 Ingår i: Social networks. - Cham : Springer. - 9783319029924 - 9783319374871 - 9783319029931 ; , s. 333-352 Bokkapitel (refereegranskat)abstract In this chapter we present a formal description of information management for assessment and classification in learning. The description is supported by a structure related to drama process for learning. Our logic follows the idea of invoking uncertainties using underlying categories, and the language of processes in 'drama process' is taken to be BPMN (Business Process Modelling Notation).
5.	Jarstad, Anna, 1966-, et al. (författare) Three approaches to peace : a framework for describing and exploring varieties of peace 2019 Rapport (övrigt vetenskapligt/konstnärligt)abstract For decades, peace and conflict studies have devoted more attention to conflict than to peace, and despiteits centrality, peace itself has been under-conceptualized. In this paper, we propose a theoretical frameworkand methodologies to make peace beyond the absence of war researchable. The framework is designed to capture varieties of peace between and beyond dichotomous conceptions of positive versus negative peace, or successful versus failed peace processes. To capture the complexity of peace in its empirical diversity, our framework approaches peace in three different ways: as a situation or condition in a particular locality; as a web of relationships; and as ideas or discourses about what peace is or should be. These approaches provide different avenues for researching peace, and taken together they provide a fuller picture of what peace is, how it is manifested, experienced, and understood. We argue that this framework provides a way forward in advancing conceptual understandings and empirical analyses of peace that can facilitate systematic, comparative, qualitative analyses while at the same time accounting for the complex, multifaceted nature of peace.
6.	Jarstad, Anna, et al. (författare) Varieties of peace : presentation of a research program 2017 Rapport (övrigt vetenskapligt/konstnärligt)abstract The Varieties of Peace research program aims to analyze long-term effects of peace processes in conflicts that ended in the 1990s. The central research questions are: What characterizes peace after the peace processes initiated in the 1990s and how does it vary? How can this variation be described and explained? Peace processes have been studied using short time perspectives, usually in "lessons-learned" evaluations five years after conflict termination, and usually with theories of conflict as a starting point. The Varieties of Peace research program is an ambitious initiative, which starts from a theoretical understanding of peace, its quality and character, and views peace and peace processes as dynamic and transformative. It will investigate and evaluate different types of peace processes from a comparative perspective and 25–30 years after they started, with the ambition of producing generalizable knowledge about peace, what it is and how it can be achieved. As a starting point, the program studies explanatory factors in five areas: 1) the actions, capacity and resilience of civil society, 2) the interests and strategies of the elites, 3) the aims and character of the agreements, 4) the societies' institutions and resilience, and 5) international involvement. These issues will be studies in at least ten projects, with the ambition to capture and explain variation, internal dynamics and ultimately the results and effects of peace processes, studied over a longer period of time. The Varieties of Peace program is funded by Riksbankens Jubileumsfond: the Swedish Foundation for Humanities and Social Sciences, 2017-2024. For more info, please visit our webpage at www.varietiesofpeace.net.
7.	Aaij, R., et al. (författare) A model-independent measurement of the CKM angle γ in partially reconstructed B±→D∗h± decays with D→K0Sh+h-(h=π,K) 2024 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :2 Tidskriftsartikel (refereegranskat)abstract A measurement of CP-violating observables in B± → D∗K± and B± → D∗π±decays is made where the photon or neutral pion from the D∗ → Dγ or D∗ → Dπ0 decayis not reconstructed. The D meson is reconstructed in the self-conjugate decay modes,D → K0Sπ+π− or D → K0SK+K−. The distribution of signal yields in the D decay phasespace is analysed in a model-independent way. The measurement uses a data sample collectedin proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV, corresponding toa total integrated luminosity of approximately 9 fb−1. The B± → D∗K± and B± → D∗π±CP-violating observables are interpreted in terms of hadronic parameters and the CKM angleγ, resulting in a measurement of γ = (92+21−17)◦. The total uncertainty includes the statisticaland systematic uncertainties, and the uncertainty due to external strong-phase inputs.
8.	Aaij, R., et al. (författare) A search for rare B → Dμ+μ− decays 2024 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; 2024:2 Tidskriftsartikel (refereegranskat)abstract A search for rare B → Dμ+μ− decays is performed using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. No significant signals are observed in the non-resonant μ+μ− modes, and upper limits of B(B0 → D0μ+μ−)< 5.1 × 10−8, B (B+ → D+s μ+μ−) < 3.2 × 10−8, B(B0s → D0μ+μ−)<1.6 × 10−7 and fc/fu · B (B+c → D+s μ+μ−) < 9.6 × 10−8 are set at the 95 % confidencelevel, where fc and fu are the fragmentation fractions of a B meson with a c and u quarkrespectively in proton-proton collisions. Each result is either the first such measurement oran improvement by three orders of magnitude on an existing limit. Separate upper limits arecalculated when the muon pair originates from a J/ψ → μ+μ− decay. The branching fractionof B+c → D+s J/ψ multiplied by the fragmentation-fraction ratio is measured to befc/fu · B(B+c → D+s J/ψ)= (1.63 ± 0.15 ± 0.13) × 10−5,where the first uncertainty is statistical and the second systematic.
9.	Aaij, R., et al. (författare) 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± 2023 Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. Tidskriftsartikel (refereegranskat)abstract The first study of CP violation in the decay mode B-+/- -> [K+K-pi(+)pi(-)](D)h(+/-), with h = K, pi, is presented, exploiting a data sample of proton-proton collisions collected by the LHCb experiment that corresponds to an integrated luminosity of 9fb(-1). The analysis is performed in bins of phase space, which are optimised for sensitivity to local CP asymmetries. CP-violating observables that are sensitive to the angle gamma of the Unitarity Triangle are determined. The analysis requires external information on charm-decay parameters, which are currently taken from an amplitude analysis of LHCb data, but can be updated in the future when direct measurements become available. Measurements are also performed of phase-space integrated observables for B-+/- -> [K+K-pi(+)pi(-)](D)h(+/-) and B-+/- -> [pi(+)pi(-)pi(+)pi(-)](D)h(+/-) decays.
10.	Aaij, R., et al. (författare) Amplitude analysis of B0? : D0Ds+p - and B plus ? D -Ds plus p plus decays 2023 Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 108:1 Tidskriftsartikel (refereegranskat)abstract Resonant contributions in B0 & RARR; over bar D0D+s & pi;- and B+ & RARR; D-D+s & pi;+ decays are determined with an amplitude analysis, which is performed both separately and simultaneously, where in the latter case isospin symmetry between the decays is assumed. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb-1. A doubly charged spin-0 open-charm tetraquark candidate together with a neutral partner, both with masses near 2.9 GeV, are observed in the Ds & pi; decay channel.
11.	Aaij, R., et al. (författare) Amplitude Analysis of the B0 → K0 μ+μ- Decay 2024 Ingår i:* Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 132:13 Tidskriftsartikel (refereegranskat)abstract An amplitude analysis of the B0 → K*0μ+μ- decay is presented using a dataset corresponding to an integrated luminosity of 4.7 fb-1 of pp collision data collected with the LHCb experiment. For the first time, the coefficients associated to short-distance physics effects, sensitive to processes beyond the standard model, are extracted directly from the data through a q2-unbinned amplitude analysis, where q2 is the μ+μ- invariant mass squared. Long-distance contributions, which originate from nonfactorizable QCD processes, are systematically investigated, and the most accurate assessment to date of their impact on the physical observables is obtained. The pattern of measured corrections to the short-distance couplings is found to be consistent with previous analyses of b- to s-quark transitions, with the largest discrepancy from the standard model predictions found to be at the level of 1.8 standard deviations. The global significance of the observed differences in the decay is 1.4 standard deviations.
12.	Aaij, R., et al. (författare) Amplitude analysis of the D+s â†’ Ï€-Ï€+Ï€+ decay 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :7 Tidskriftsartikel (refereegranskat)abstract A Dalitz plot analysis of the D-s(+) -> pi(-)pi(+)pi(+) decay is presented. The analysis is based on proton-proton collision data recorded by the LHCb experiment at a centre-of-mass energy of 8TeV and corresponding to an integrated luminosity of 1.5 fb(-1). The resonant structure of the decay is obtained using a quasi-model-independent partial-wave analysis, in which the pi(+)pi(-) S-wave amplitude is parameterised as a generic complex function determined by a fit to the data. The S-wave component is found to be dominant, followed by the contribution from spin-2 resonances and a small contribution from spin-1 resonances. The latter includes the first observation of the D-s(+) -> omega(782)pi(+) channel in the D-s(+) -> pi(-)pi(+)pi(+) decay. The resonant structures of the D-s(+) -> pi(-)pi(+)pi(+) and D+ -> pi(-)pi(+)pi(+) decays are compared, providing information about the mechanisms for the hadron formation in these decays.
13.	Aaij, R., et al. (författare) Associated production of prompt J/Ψ and Υ mesons in pp collisions at √ˆšs=13 TeV 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)abstract The associated production of prompt J/psi and (sic) mesons in pp collisions at a centre-of-mass energy of root s = 13TeV is studied using LHCb data, corresponding to an integrated luminosity of 4 fb(-1). The measurement is performed for J/psi (sic) mesons with a transverse momentum pT < 10 (30) GeV/ c in the rapidity range 2.0 < y < 4.5. In this kinematic range, the cross-section of the associated production of prompt J/psi and (sic)(1S) mesons is measured to be 133 +/- 22 +/- 7 +/- 3 pb, with a significance of 7.9 s, and that of prompt J/psi and (sic)(2S) mesons to be 76 +/- 21 +/- 4 +/- 7 pb, with a significance of 4.9 sigma. The first uncertainty is statistical, the second systematic, and the third due to uncertainties on the used branching fractions. This is the first observation of the associated production of J/psi and (sic)(1S) in proton-proton collisions. Differential cross-sections are measured as functions of variables that are sensitive to kinematic correlations between the J/psi and (sic)(1S) mesons. The effective cross-sections of the associated production of prompt J/psi and (sic) mesons are obtained and found to be compatible with measurements using other particle productions.
14.	Aaij, R., et al. (författare) Evidence for the decays B0 → ()0ϕ and updated measurements of the branching fractions of the Bs0 → D‾()0ϕ decays 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :10 Tidskriftsartikel (refereegranskat)abstract Evidence for the decays B-0 -> (D) over bar (0)phi and B-0 -> (D) over bar (0) phi is reported with a significance of 3.6 sigma and 4.3 sigma, respectively. The analysis employs pp collision data at centre-of-mass energies root s = 7, 8 and 13TeV collected by the LHCb detector and corresponding to an integrated luminosity of 9 fb(-1). The branching fractions are measured to be B(B-0 -> (D) over bar (0)phi) = (7.7 +/- 2.1 +/- 0.7 +/- 0.7) x 10(-7), B(B-0 -> (D) over bar (0)phi) = (2.2 +/- 05 +/- 0.2 +/- 0.2) x 10(-6). In these results, the first uncertainty is statistical, the second systematic, and the third is related to the branching fraction of the B-0 -> (D) over bar K-0(+) K- decay, used for normalisation. By combining the branching fractions of the decays B-0 -> (D) over bar (()0)phi and B-0 -> (D) over bar (()0)omega, the omega-phi mixing angle delta is constrained to be tan(2)delta = (3.6 +/- 0.7 +/- 0.4) x 10(-3), where the first uncertainty is statistical and the second systematic. An updated measurement of the branching fractions of the B-s(0) -> (D) over bar (()0).phi decays, which can be used to determine the CKM angle gamma, leads to B(B-s(0) -> (D) over bar (0)phi) = (2.30 +/- 0.10 +/- 0.11 +/- 0.20) x 10(-5), B(B-s(0) -> (D) over bar (0)phi) = (3.17 +/- 0.16 +/- 0.17 +/- 0.27) x 10(-5).
15.	Aaij, R., et al. (författare) Evidence of a J/ψK0S Structure in B0 → J/ψϕK0S Decays 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:13 Tidskriftsartikel (refereegranskat)abstract An amplitude analysis of B0 → J/ψϕK0S decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. Evidence with a significance of 4.0 standard deviations of a structure in the J/ψK0S system, named Tθψs1(4000)0, is seen, with its mass and width measured to be 3991+12−10 +9−17 MeV/c2 and 105+29−25 +17−23 MeV, respectively, where the first uncertainty is statistical and the second systematic. The Tθψs1(4000)0 state is likely to be the isospin partner of the Tθψs1(4000)+ state, previously observed in the J/ψK+ system of the B+ → J/ψϕK+ decay. When isospin symmetry for the charged and neutral Tθψs1(4000) states is assumed, the signal significance increases to 5.4 standard deviations.
16.	Aaij, R., et al. (författare) First observation and branching fraction measurement of the Λ›b0 →†’ Ds- p decay 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)abstract The first observation of the Lambda(0)(b) -> D-s(-) p decay is presented using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of root s = 13TeV, corresponding to a total integrated luminosity of 6 fb(-1). Using the Lambda(0)(b) -> Lambda(+pi-)(c) decay as the normalisation mode, the branching fraction of the Lambda(0)(b) -> D-s(-) p decay is measured to be B (Lambda(0)(b) -> D-s(-) p) = (12.6 +/- 0.5 +/- 0.3 +/- 1.2) x 10(-6), where the first uncertainty is statistical, the second systematic and the third due to uncertainties in the branching fractions of the Lambda(0)(b) -> Lambda(+pi-)(c), D-s(-) -> K-K+pi(-) and Lambda(+)(c) -> pK(-)pi(+) decays.
17.	Aaij, R., et al. (författare) First Observation of a Doubly Charged Tetraquark and Its Neutral Partner 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:4 Tidskriftsartikel (refereegranskat)abstract A combined amplitude analysis is performed for the decays B0-+ D0D thorn s & pi;- and B thorn -+ D-D thorn s & pi; thorn , which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton -proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb-1. Two new resonant states with masses of 2.908 â ‚ 0.011 â ‚ 0.020 GeV and widths of 0.136 â ‚ 0.023 â ‚ 0.013 GeV are observed, which decay to D thorn s & pi; thorn and D thorn s & pi;- respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content 1/2cs over bar ud over bar â ƒ, and the latter state is a neutral tetraquark composed of 1/2cs over bar u over bar d â ƒ quarks. Both states are found to have spin-parity of 0 thorn , and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.
18.	Aaij, R., et al. (författare) Improved Measurement of CP Violation Parameters in B0s→J/ψK+K− Decays in the Vicinity of the ϕ(1020) Resonance 2024 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 132:5 Tidskriftsartikel (refereegranskat)abstract The decay-time-dependent CP asymmetry in B0s→J/ψ(→μ+μ−)K+K− decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb−1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 B0s signal decays with an invariant K+K− mass in the vicinity of the ϕ(1020) resonance, the CP-violating phase ϕs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the B0s−¯B0s system, ΔΓs, and the difference of the average B0s and B0 meson decay widths, Γs−Γd. The values obtained are ϕs=−0.039±0.022±0.006 rad, ΔΓs=0.0845±0.0044±0.0024 ps−1, and Γs−Γd=−0.0056+0.0013−0.0015±0.0014 ps−1, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase ϕs is also measured independently for each polarization state of the K+K− system and shows no evidence for polarization dependence.
19.	Aaij, R., et al. (författare) Measurement of CP asymmetries and branching fraction ratios of B- decays to two charm mesons 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :9 Tidskriftsartikel (refereegranskat)abstract The CP asymmetries of seven B- decays to two charm mesons are measured using data corresponding to an integrated luminosity of 9 fb(-1) of proton-proton collisions collected by the LHCb experiment. Decays involving a D(0) or D-s(-) meson are analysed by reconstructing only the D-0 or D-s(-) decay products. This paper presents the first measurement of A(CP) (B- -> D-s(-) D-0) and A(CP) (B- -> D-s(-) D(0)), and the most precise measurement of the other five CP asymmetries. There is no evidence of CP violation in any of the analysed decays. Additionally, two ratios between branching fractions of selected decays are measured.
20.	Aaij, R., et al. (författare) Measurement of J/ψ-pair production in pp collisions at √‾s = 13 TeV and study of gluon transverse-momentum dependent PDFs 2024 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :3 Tidskriftsartikel (refereegranskat)abstract The production cross-section of J/ψ pairs in proton-proton collisions at a centre-of-mass energy of s√ = 13 TeV is measured using a data sample corresponding to an integrated luminosity of 4.2 fb−1 collected by the LHCb experiment. The measurement is performed with both J/ψ mesons in the transverse momentum range 0 < pT < 14 GeV/c and rapidity range 2.0 < y < 4.5. The cross-section of this process is measured to be 16.36 ± 0.28 (stat) ± 0.88 (syst) nb. The contributions from single-parton scattering and double-parton scattering are separated based on the dependence of the cross-section on the absolute rapidity difference ∆y between the two J/ψ mesons. The effective cross-section of double-parton scattering is measured to be σeff = 13.1 ± 1.8 (stat) ± 2.3 (syst) mb. The distribution of the azimuthal angle ϕCS of one of the J/ψ mesons in the Collins-Soper frame and the pT-spectrum of the J/ψ pairs are also measured for the study of the gluon transverse-momentum dependent distributions inside protons. The extracted values of ⟨cos 2ϕCS⟩ and ⟨cos 4ϕCS⟩ are consistent with zero, but the presence of azimuthal asymmetry at a few percent level is allowed.
21.	Aaij, R., et al. (författare) Measurement of lepton universality parameters in B plus ? : K plus l + l - and B0? K?0l+l- decays 2023 Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 108:3 Tidskriftsartikel (refereegranskat)abstract A simultaneous analysis of the B thorn & RARR; K thorn e thorn e- and B0 & RARR; K & DBLBOND;0e thorn e- decays is performed to test muonelectron universality in two ranges of the square of the dilepton invariant mass, q2. The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb-1. A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given q2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.
22.	Aaij, R., et al. (författare) Measurement of prompt D+ and Ds+ production in pPb collisions at √ˆšsNN=5.02 TeV 2024 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)abstract The production of prompt D+ and D+s mesons is studied in proton-lead collisions at a centre-of-mass energy of √sNN = 5.02TeV. The data sample corresponding to an integrated luminosity of (1.58 ± 0.02)nb-1 is collected by the LHCb experiment at the LHC. The differential production cross-sections are measured using D+ and D+s candidates with transverse momentum in the range of 0 < pT < 14 GeV/c and rapidities in the ranges of 1.5 < y* < 4.0 and -5.0 < y* < -2.5 in the nucleon-nucleon centre-of-mass system. For both particles, the nuclear modification factor and the forward-backward production ratio are determined. These results are compared with theoretical models that include initial-state nuclear effects. In addition, measurements of the cross-section ratios between D+, D+s and D0 mesons are presented, providing a baseline for studying the charm hadronization in lead-lead collisions at LHC energies.
23.	Aaij, R., et al. (författare) Measurement of the Branching Fractions B(B0→p¯pp¯p) and B(B0s→p¯pp¯p) 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:9 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.
24.	Aaij, R., et al. (författare) Measurement of the CKM angle γ using the B±→†’ Dh± 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.
25.	Aaij, R., et al. (författare) Measurement of the Î›b0 â†’ Î›(1520)ÎŒ+ÎŒ- Differential Branching Fraction 2023 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.
26.	Aaij, R., et al. (författare) 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.
27.	Aaij, R., et al. (författare) Measurement of the ratio of branching fractions B (B+c → B0sπ+) /B (B+c →†’ J/ψπ+) 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :7 Tidskriftsartikel (refereegranskat)abstract The ratio of branching fractions of B+c → B0sπ+ and B+c → J/ψπ+ decays is measured with proton-proton collision data of a centre-of-mass energy of 13TeV. The data were collected with the LHCb experiment during 2016-2018, corresponding to an integrated luminosity of 5.4 fb-1. The B0s mesons are reconstructed via the decays B0s → J/ψφ and B0s → D‾sπ+. The ratio of branching fractions is measured to be B (B+c → B0sπ+) /B (B+c →†’ J/ψπ+) = 91 ± 10 ± 8 ± 3 where the first uncertainty is statistical, the second is systematic and the third is due to the knowledge of the branching fractions of the intermediate state decays.
28.	Aaij, R., et al. (författare) Measurement of the Ratios of Branching Fractions R(D) and R(D0) 2023 Ingår i:* Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:11 Tidskriftsartikel (refereegranskat)abstract The ratios of branching fractions R(D) = B((B) over bar -> D tau(-) (v) over bar (tau))/B((B) over bar -> D*.mu(-)(v) over bar mu) and R(D-0) = B(B- -> D(0)t-mu(-)(v) over bar mu) are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb(-1) of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode tau(-) -> mu(-)v(tau)(v) over bar mu. The measured values are R(D) = 0.281 +/- 0.018 +/- 0.024 and R(D-0) = 0.441 +/- 0.060 +/- 0.066, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is rho = -0.43. The results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the standard model.
29.	Aaij, R., et al. (författare) Measurement of the Time-Integrated CP Asymmetry in D0 → K-K+ Decays 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:9 Tidskriftsartikel (refereegranskat)abstract The time-integrated CP asymmetry in the Cabibbo suppressed decay PKK is measured using proton proton collision data, corresponding to an integrated luminosity of 5.7 th collected at a center of mass energy of 13 TeV with the LHCb detector. The D mesons are required to originate from promptly produced DD's decays, and the charge of the companion pion is used to determine the flavor of the charm meson at production. The time integrated CP asymmetry is measured to be Acr(KK) 6,815.41.6 x 10 where the first uncertainty is statistical and the second systematic. The direct CP asymmetries in D-K-K and D -> decays, and are derived by combining Ace(KK) with the time integrated CP asymmetry differ ence, AAcr-Acr(KK)-A(x), and other inputs, giving a (7.715.7) x 10, (23.2 16.1) x 10, with a correlation coefficient corresponding to p=0.88. The compatibility of these results with CP symmetry is 1.4 and 3.8 standard deviations for DKK and D degrees-xx decays, respectively. This is the first evidence for direct CP violation in a specific Do decay.
30.	Aaij, R., et al. (författare) Measurement of the Z boson production cross-section in pp pcollisions at √ˆšs=5.02TeV 2024 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; 2024:2 Tidskriftsartikel (refereegranskat)abstract The first measurement of the Z boson production cross-section at centre-of-massenergy √s = 5.02 TeV in the forward region is reported, using pp collision data collected bythe LHCb experiment in year 2017, corresponding to an integrated luminosity of 100 ± 2 pb−1.The production cross-section is measured for final-state muons in the pseudorapidity range2.0 < η < 4.5 with transverse momentum pT > 20 GeV/c. The integrated cross-sectionis determined to beσZ→μ+μ− = 39.6 ± 0.7(stat) ± 0.6(syst) ± 0.8(lumi) pbfor the di-muon invariant mass in the range 60 < Mμμ < 120 GeV/c2. This result andthe differential cross-section results are in good agreement with theoretical predictions atnext-to-next-to-leading order in the strong coupling constant.Based on a previous LHCb measurement of the Z boson production cross-section in pPbcollisions at √sNN = 5.02 TeV, the nuclear modification factor RpPb is measured for the firsttime at this energy. The measured values are 1.2+0.5−0.3(stat) ± 0.1(syst) in the forward region(1.53 < y∗μ < 4.03) and 3.6+1.6−0.9(stat) ± 0.2 (syst) in the backward region (−4.97 < y∗μ < −2.47),where y∗μ represents the muon rapidity in the centre-of-mass frame.
31.	Aaij, R., et al. (författare) Measurement of Ξ+? production in ?⁢Pb collisions at √??⁢? = 8.16 TeV at LHCb 2024 Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 109:4 Tidskriftsartikel (refereegranskat)abstract A study of prompt Ξ+? production in proton-lead collisions is performed with the LHCb experiment at a center-of-mass energy per nucleon pair of 8.16 TeV in 2016 in ?⁢Pb and Pb⁢? collisions with an estimated integrated luminosity of approximately 12.5 and 17.4 nb−1, respectively. The Ξ+? production cross section, as well as the Ξ+? to Λ+? production cross-section ratio, are measured as a function of the transverse momentum and rapidity and compared to the latest theory predictions. The forward-backward asymmetry is also measured as a function of the Ξ+? transverse momentum. The results provide strong constraints on theoretical calculation and are a unique input for hadronization studies in different collision systems.
32.	Aaij, R., et al. (författare) Measurement of Υ production in pp collisions at √ˆšs=5 TeV 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)abstract The production cross-sections of Υ mesons, namely Υ(1S), Υ(2S) anΥ(3S), in pp collisions at root s = 5TeV are measured with a data sample corresponding to an integrated luminosity of 9.13 +/- 0.18 pb(-1) collected by the LHCb detector. The (sic) mesons are reconstructed in the decay mode Υ -> mu(+)mu(-). Double differential cross-sections times branching fractions, as functions of the transverse momentum p(T) and the rapidity y of the (sic) mesons, are measured in the range pT < 20 GeV/ c and 2.0 < y < 4.5. The results integrated over these pT and y ranges are sigma(Υ(1S)) x B(Υ(1S) -> mu(+) mu(-)) = 2101 +/- 33 +/- 83 pb, sigma(Υ(2S)) x B(Υ(2S) -> mu(+) mu(-)) = 526 +/- 20 +/- 21 pb, sigma(Υ(3S)) x B(Υ(3S) -> mu(+) mu(-)) = 242 +/- 16 +/- 10 pb, where the first uncertainties are statistical and the second are systematic. The ratios of cross-sections between measurements of two different (sic) states and between measurements at different centre-of-mass energies are determined. The nuclear modification factor of Υ(1S) at root s = 5TeV is updated as well using the directly measured cross-section results from this analysis.
33.	Aaij, R., et al. (författare) Observation and branching fraction measurement of the decay Ξ−b → Λ0bπ− 2023 Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 108:7 Tidskriftsartikel (refereegranskat)abstract The decay E-b -> A0bx-- is observed using a proton-proton collision data sample collected at center-of-ffiffimass energy p s 1/4 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 5.5 fb-1. This process is mediated by the s -> uu over bar d quark-level transition, where the b quark in the E-b baryon is a spectator in the decay. Averaging the results obtained using the two A0b decay modes, A0b -> A thorn c x-- and A0b -> A thorn c x--x- thorn x--, the relative production ratio is measured to be ofE-b =fA0b thorn BoE-b -> A0bx-- thorn 1/4 o7.3 â ‚ 0.8 â ‚ 0.6 thorn x 10-4. Here the uncertainties are statistical and systematic, respectively, and fE-bofA0b thorn is the fragmentation fraction for a b quark into a E-b (A0b) baryon. Using an independent measurement of fE-b =fA0b, the branching fraction BoE-b -> A0bx-- thorn 1/4 o0.89 â ‚ 0.10 â ‚ 0.07 â ‚ 0.29 thorn % is obtained, where the last uncertainty is due to the assumed SU(3) flavor symmetry in the determination of fE-b =fA0b.
34.	Aaij, R., et al. (författare) Observation of a J/ΨΛ Resonance Consistent with a Strange Pentaquark Candidate in B- →†’ J/ψΛ(p)over-bar Decays 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:3 Tidskriftsartikel (refereegranskat)abstract An amplitude analysis of B- -> J/psi Lambda(p) over bar decays is performed using 4400 signal candidates selected on a data sample of pp collisions recorded at center-of-mass energies of 7, 8, and 13 TeV with the LHCb detector, corresponding to an integrated luminosity of 9 fb(-1). A narrow resonance in the J/psi Lambda system, consistent with a pentaquark candidate with strangeness, is observed with high significance. The mass and the width of this new state are measured to be 4338.2 +/- 0.7 +/- 0.4 MeV and 7.0 +/- 1.2 +/- 1.3 MeV, where the first uncertainty is statistical and the second systematic. The spin is determined to be 1/2 and negative parity is preferred. Because of the small Q-value of the reaction, the most precise single measurement of the B- mass to date, 5279.44 +/- 0.05 +/- 0.07 MeV, is obtained.
35.	Aaij, R., et al. (författare) Observation of Cabibbo-Suppressed Two-Body Hadronic Decays and Precision Mass Measurement of the Ωc0 Baryon 2024 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 132:8 Tidskriftsartikel (refereegranskat)abstract The first observation of the singly Cabibbo-suppressed Ωc0 → Ω-K+ and Ωc0 → Ξ-π+ decays is reported, using proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb-1, collected with the LHCb detector between 2016 and 2018. The branching fraction ratios are measured to beB(Ωc0 → Ω-K+) / B(Ωc0 → Ω-π+) = [6.08 ± ‚0.51 (stat) ± ‚0.40 (syst)]ƒ%, B(Ωc0 → Ξ-π+) / B(Ωc0 → Ω-π+) = [15.81 ± ‚0.87(stat) ± 0.44(syst) ± ‚0.16(ext)ƒ%.In addition, using the Ωc0 → Ω-π+ decay channel, the Ωc0 baryon mass is measured to be M(Ωc0) = 2695.28 ± ‚0.07(stat) ±‚ 0.27(syst) ±‚ 0.30(ext) MeV, improving the precision of the previous world average by a factor of 4.
36.	Aaij, R., et al. (författare) Observation of New Baryons in the Ξ−bπ+π− and Ξ0bπ+π− Systems 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:17 Tidskriftsartikel (refereegranskat)abstract The first observation and study of two new baryonic structures in the final state Xi(0)(b)pi(+)pi(-) and the confirmation of the Xi(b)(6100)(-) state in the Xi(-)(b)pi(+)pi(-) decay mode are reported using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1). In addition, the properties of the known Xi(b)(0), Xi(b)'(-) and Xi(b)(-) resonances are measured with improved precision. The new decay mode of the Xi(0)(b) baryon to the Xi(+)(c) pi(-) pi(+) pi(-) final state is observed and exploited for the first time in these measurements.
37.	Aaij, R., et al. (författare) Observation of New Ω0c States Decaying to the Ξ+cK− Final State 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:13 Tidskriftsartikel (refereegranskat)abstract Two new excited states, Ωc(3185)0 and Ωc(3327)0, are observed in the Ξ+cK− invariant-mass spectrum using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. Five previously observed excited Ω0c states are confirmed, namely Ωc(3000)0, Ωc(3050)0, Ωc(3065)0, Ωc(3090)0, and Ωc(3119)0. The masses and widths of these seven states are measured with the highest precision to date.
38.	Aaij, R., et al. (författare) Observation of the B+ →†’ Jψη'K+ decay 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)abstract The B+ → Jψη'K+ decay is observed for the first time 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. The branching fraction of this decay is measured relative to the known branching fraction of the B+ → ψ(2S)K+ decay and found to be B(B+ → Jψη'K+)/B(B+ → ψ(2S)K+) = (4.91 ± 0.47 ± 0.29 ± 0.07) x 10-2, where the first uncertainty is statistical, the second is systematic and the third is related to external branching fractions. A first look at the J/ψη' mass distribution is performed and no signal of intermediate resonances is observed.
39.	Aaij, R., et al. (författare) Observation of the B0s â†’ D+ D- decay 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :7 Tidskriftsartikel (refereegranskat)abstract The first observation of the B-s(0) -> D+ D- decay and the measurement of its branching ratio relative to the B-0 -> D+ D(-) decay are presented. The data sample used corresponds to an integrated luminosity of 9 fb(-1) of proton-proton collisions recorded by the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018. The decay is observed with more than 10 standard deviations and the time-integrated ratio of branching fractions is determined to be [GRAPHICS] . where the first uncertainty is statistical, the second systematic and the third due to the uncertainty of the fragmentation fraction ratio f(s)/f(d). The B-s(0) -> D(+) D(-) branching fraction is calculated to be [GRAPHICS] . where the fourth uncertainty is due to the B-0 -> D(+) D(-) branching fraction. These results are calculated using the average B-s(0) meson lifetime in simulation. Correction factors are reported for scenarios where either a purely heavy or a purely light B-s(0) eigenstate is considered.
40.	Aaij, R., et al. (författare) Observation of the B0s â†’ Ï‡c1(3872)Ï€+Ï€- decay 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :7 Tidskriftsartikel (refereegranskat)abstract The first observation of the B-s(0) -> (chi(c1)(3872) -> J/Psi pi(broken vertical bar) pi(-)) pi(broken vertical bar) pi(-) decay is reported using proton-proton collision data, corresponding to integrated luminosities of 1, 2 and 6 fb(-1), collected by the LHCb experiment at centre-of-mass energies of 7, 8 and 13TeV, respectively. The ratio of branching fractions relative to the B-s(0) -> (Psi(2S) -> J/Psi pi(+) pi(-)) pi(+) pi(-) decay is measured to be [GRAPHICS] where the first uncertainty is statistical and the second systematic. The mass spectrum of the pi(+) pi(-) system recoiling against the chi(c1)(3872) meson exhibits a large contribution from B-s(0) -> chi(c1)(3872) (integral(0)(980) -> pi(+) pi(-)) decays.
41.	Aaij, R., et al. (författare) Observation of the decays B(s)0 →†’ Ds1(2536)∓ˆ“K± 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. Tidskriftsartikel (refereegranskat)abstract This paper reports the observation of the decays B-(s)(0) -> D-s1(2536)K--/+(+/-) using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb(-1). The branching fractions of these decays are measured relative to the normalisation channel B-0 -> (D) over bar (K+K-)-K-0. The D-s1(2536)(-) meson is reconstructed in the (D) over bar(2007)K-0(-) decay channel and the products of branching fractions are measured to be B(B-s(0) -> D-s1(2536)K--/+(+/-)) x B(D-s1(2536)(-) -> D ($) over bar(2007)K-0(-)) = (2.49 +/- 0.11 +/- 0.12 +/- 0.25 +/- 0.06) x 10(-5), B(B-0 -> D-s1(2536)K--/+(+/-) ) x B(D-s1(2536)(-) -> (D) over bar(2007)K-0(-)) = (0.510 +/- 0.021 +/- 0.036 +/- 0.050) x 10(-5). The first uncertainty is statistical, the second systematic, and the third arises from the uncertainty of the branching fraction of the B-0 -> (D) over bar (K+K-)-K-0 normalisation channel. The last uncertainty in the B-s(0) result is due to the limited knowledge of the fragmentation fraction ratio, f(s)/f(d). The significance for the B-s(0) and B-0 signals is larger than 10 sigma. The ratio of the helicity amplitudes which governs the angular distribution of the D-s1(2536)(-) -> (D) over bar(2007)K-0(-) decay is determined from the data. The ratio of the S- and D-wave amplitudes is found to be 1.11 +/- 0.15 +/- 0.06 and the phase difference between them 0.70 +/- 0.09 +/- 0.04 rad, where the first uncertainty is statistical and the second systematic.
42.	Aaij, R., et al. (författare) Open charm production and asymmetry in pNe collisions at âˆšsNN=68.5 GeV 2023 Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 83 Tidskriftsartikel (refereegranskat)abstract A measurement of D-0 meson production by the LHCb experiment in its fixed-target configuration is presented. The production of D-0 mesons is studied with a beam of 2.5 TeV protons colliding on a gaseous neon target at rest, corresponding to a nucleon-nucleon centre-of-mass energy of root s(NN) = 68.5 GeV. The sum of the D-0 and (D-0) over bar production cross-section in pNe collisions in the centre-of-mass rapidity range y(star) is an element of[-2.29, 0] is found to be sigma(y star is an element of[-2.29, 0])(D0) = 48.2 +/- 0.3 +/- 4.5 mu b/nucleon where the first uncertainty is statistical and the second is systematic. The D-0 - (D-0) over bar production asymmetry is also evaluated and suggests a trend towards negative values at large negative y(star). The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1% intrinsic charm and 10% recombination contributions better describe the data than the other models considered.
43.	Aaij, R., et al. (författare) Precision Measurement of CP Violation in the Penguin-Mediated Decay B0s → ϕϕ 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:17 Tidskriftsartikel (refereegranskat)abstract A flavor-tagged time-dependent angular analysis of the decay B0s -> phi phi is performed using pp collision integrated luminosity of 6 fb-1. The CP-violating phase and direct CP-violation parameter are measured to s = -0.042 +/- 0.075 +/- 0.009 rad and l lambda l = 1.004 +/- 0.030 +/- 0.009, respectively, assuming the same values for all polarization states of the phi phi system. In these results, the first uncertainties are statistical and the second systematic. These parameters are also determined separately for each polarization state, showing no evidence for polarization dependence. The results are combined with previous LHCb measurements using pp collisions at center-of-mass energies of 7 and 8 TeV, yielding phi sss over bar s = -0.074 +/- 0.069 rad and l lambda l = 1.009 +/- 0.030. This is the most precise study of time-dependent CP violation in a penguindominated B meson decay. The results are consistent with CP symmetry and with the standard model predictions.
44.	Aaij, R., et al. (författare) Production of ? and ?′ mesons in ?⁢? and ?⁢Pb collisions 2024 Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 109:2 Tidskriftsartikel (refereegranskat)abstract The production of ? and ?′ mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.02 and 13TeV and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16TeV. The studies are performed in center-of-mass (c.m.) rapidity regions 2.5<?c.m.<3.5 (forward rapidity) and −4.0<?c.m.<−3.0 (backward rapidity) defined relative to the proton beam direction. The ? and ?′ production cross sections are measured differentially as a function of transverse momentum for 1.5<?T<10GeV and 3<?T<10GeV, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for ? and ?′ mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of ? mesons are also used to calculate ?/?0 cross-section ratios, which show evidence of a deviation from the world average. These studies offer new constraints on mass-dependent nuclear effects in heavy-ion collisions, as well as ? and ?′ meson fragmentation.
45.	Aaij, R., et al. (författare) Prompt and nonprompt ψ(2S) production in pPb collisions at √sNN = 8.16 TeV 2024 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :4 Tidskriftsartikel (refereegranskat)abstract The production of ψ(2S) mesons in proton-lead collisions at a centre-of-mass energy per nucleon pair of √sNN = 8.16 TeV is studied with the LHCb detector using data corresponding to an integrated luminosity of 34 nb−1. The prompt and nonprompt ψ(2S) production cross-sections and the ratio of the ψ(2S) to J/ψ cross-section are measured as a function of the meson transverse momentum and rapidity in the nucleon-nucleon centre-of-mass frame, together with forward-to-backward ratios and nuclear modification factors. The production of prompt ψ(2S) is observed to be more suppressed compared to pp collisions than the prompt J/ψ production, while the nonprompt productions have similar suppression factors.
46.	Aaij, R., et al. (författare) Search for ?0S⁡(L)→?+⁢?−⁢?+⁢?− decays at LHCb 2023 Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 108:3 Tidskriftsartikel (refereegranskat)abstract A search for ?0S⁡(L)→?+⁢?−⁢?+⁢?− decays is performed using proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.1 fb−1. No evidence for signal is found. The 90% confidence level upper limits are the first set for both decays and are ℬ⁡(?0S→?+⁢?−⁢?+⁢?−)<5.1×10−12 and ℬ⁡(?0L→?+⁢?−⁢?+⁢?−)<2.3×10−9.
47.	Aaij, R., et al. (författare) Search for CP violation in D(s)+ â†’ K- K+ K+ decays 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer. - 1126-6708 .- 1029-8479. ; :7 Tidskriftsartikel (refereegranskat)abstract A search for direct CP violation in the Cabibbo-suppressed decay D-s(+) -> K-K+ K+ and in the doubly Cabibbo-suppressed decay D+ -> K- K+ K+ is reported. The analysis is performed with data collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of 13TeV corresponding to an integrated luminosity of 5.6 fb(-1). The search is conducted by comparing the D-(s)(+) and D-(s)(-) Dalitz-plot distributions through a model-independent binned technique, based on fits to the K-K+K+ invariantmass distributions, with a total of 0.97 (1.27) million D-s(+) (D+) signal candidates. The results are given as p-values for the hypothesis of CP conservation and are found to be 13.3% for the D+ -> K-K+ K+ decay and 31.6% for the D+ -> K-K+ K+ decay. No evidence for CP violation is observed in these decays.
48.	Aaij, R., et al. (författare) Search for CP violation in the phase space of D0 → π−π+π0 decays with the energy test 2023 Ingår i: Journal of High Energy Physics (JHEP). - : Springer Nature. - 1126-6708 .- 1029-8479. ; :9 Tidskriftsartikel (refereegranskat)abstract A search for CP violation in D-0 -> pi(-)pi(+)pi(0) decays is reported, using pp collision data collected by the LHCb experiment from 2015 to 2018 corresponding to an integrated luminosity of 6 fb(-1). An unbinned model-independent approach provides sensitivity to local CP violation within the two-dimensional phase space of the decay. The method is validated using the Cabibbo-favoured channel D-0 -> K-pi(+)pi(0) and background regions of the signal mode. The results are consistent with CP symmetry in this decay.
49.	Aaij, R., et al. (författare) Search for D* (2007)0 → μ+ μ- in B- → π- μ+ μ- decays 2023 Ingår i: European Physical Journal C. - : Springer. - 1434-6044 .- 1434-6052. ; 83:7 Tidskriftsartikel (refereegranskat)abstract The very rare D(2007)0 → μ+ μ- decay is searched for by analysing B- → π- μ+ μ- decays. The analysis uses a sample of beautymesons produced in protonproton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb-1. The signal signature corresponds to simultaneous peaks in the μ+ μ- and π- μ+ μ- invariant masses. No evidence for an excess of events over background is observed and an upper limit is set on the branching fraction of the decay at B(D(2007)0 → μ+ μ-) < 2.6 x 10-8 at 90% confidence level. This is the first limit on the branching fraction of D(2007)0 -> → μ+ μ- decays and the most stringent limit on D (2007)0 decays to leptonic final states. The analysis is the first search for a rare charm-meson decay exploiting production via beauty decays.
50.	Aaij, R., et al. (författare) Search for Rare Decays of D0 Mesons into Two Muons 2023 Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 131:4 Tidskriftsartikel (refereegranskat)abstract A search for the very rare D-0 -> mu(+)mu(-) decay is performed using data collected by the LHCb experiment in proton-proton collisions at root s = 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb(-1). The search is optimized for D-0 mesons from D*(+) -> D-0 pi(+) decays but is also sensitive to D-0 mesons from other sources. No evidence for an excess of events over the expected background is observed. An upper limit on the branching fraction of this decay is set at B(D-0 -> mu(+)mu(-)) < 3.1 x 10(-9) at a 90% C.L. This represents the world's most stringent limit, constraining models of physics beyond the standard model.

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