Publications
706 results found
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Measurement of the Prompt <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math> Nuclear Modification Factor in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>p</mml:mi><mml:mtext>−</mml:mtext><mml:mi>Pb</mml:mi></mml:mrow></mml:math> Collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mi>N</mml:mi><mml:mi>N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>8.16</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:mrow></mml:math>, Physical Review Letters, Vol: 131, ISSN: 0031-9007
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Model-independent measurement of charm mixing parameters in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mover accent="true"><mml:mi>B</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>D</mml:mi><mml:mn>0</mml:mn></mml:msup><mml:mo stretchy="false">(</mml:mo><mml:mo stretchy="false">→</mml:mo><mml:msubsup><mml:mi>K</mml:mi><mml:mi>S</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:msup><mml:mi>π</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mo stretchy="false">)</mml:mo><mml:msup><mml:mi>μ</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:msub><mml:mover accent="true"><mml:mi>ν</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover><mml:mi>μ</mml:mi></mml:msub><mml:mi>X</mml:mi></mml:math> decays, Physical Review D, Vol: 108, ISSN: 2470-0010
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Measurement of the Time-Integrated CP Asymmetry in D^{0}→K^{-}K^{+} Decays., Phys Rev Lett, Vol: 131
The time-integrated CP asymmetry in the Cabibbo-suppressed decay D^{0}→K^{-}K^{+} is measured using proton-proton collision data, corresponding to an integrated luminosity of 5.7 fb^{-1} collected at a center-of-mass energy of 13 TeV with the LHCb detector. The D^{0} mesons are required to originate from promptly produced D^{*+}→D^{0}π^{+} 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 A_{CP}(K^{-}K^{+})=[6.8±5.4±1.6]×10^{-4} where the first uncertainty is statistical and the second systematic. The direct CP asymmetries in D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays, a_{K^{-}K^{+}}^{d} and a_{π^{-}π^{+}}^{d}, are derived by combining A_{CP}(K^{-}K^{+}) with the time-integrated CP asymmetry difference, ΔA_{CP}=A_{CP}(K^{-}K^{+})-A_{CP}(π^{-}π^{+}), and other inputs, giving a_{K^{-}K^{+}}^{d}=(7.7±5.7)×10^{-4},a_{π^{-}π^{+}}^{d}=(23.2±6.1)×10^{-4},with a correlation coefficient corresponding to ρ=0.88. The compatibility of these results with CP symmetry is 1.4 and 3.8 standard deviations for D^{0}→K^{-}K^{+} and D^{0}→π^{-}π^{+} decays, respectively. This is the first evidence for direct CP violation in a specific D^{0} decay.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Measurement of the Branching Fractions B(B^{0}→pp[over ¯]pp[over ¯]) and B(B_{s}^{0}→pp[over ¯]pp[over ¯])., Phys Rev Lett, Vol: 131
Searches for the rare hadronic decays B^{0}→pp[over ¯]pp[over ¯] and B_{s}^{0}→pp[over ¯]pp[over ¯] 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 B^{0}→pp[over ¯]pp[over ¯] and B_{s}^{0}→pp[over ¯]pp[over ¯] signals, respectively. The branching fractions are measured relative to the topologically similar normalization decays B^{0}→J/ψ(→pp[over ¯])K^{*0}(→K^{+}π^{-}) and B_{s}^{0}→J/ψ(→pp[over ¯])ϕ(→K^{+}K^{-}). The branching fractions are measured to be B(B^{0}→pp[over ¯]pp[over ¯])=(2.2±0.4±0.1±0.1)×10^{-8} and B(B_{s}^{0}→pp[over ¯]pp[over ¯])=(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.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Observation of a Resonant Structure near the D_{s}^{+}D_{s}^{-} Threshold in the B^{+}→D_{s}^{+}D_{s}^{-}K^{+} Decay., Phys Rev Lett, Vol: 131
An amplitude analysis of the B^{+}→D_{s}^{+}D_{s}^{-}K^{+} decay is carried out to study for the first time its intermediate resonant contributions, using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A near-threshold peaking structure, referred to as X(3960), is observed in the D_{s}^{+}D_{s}^{-} invariant-mass spectrum with significance greater than 12 standard deviations. The mass, width, and the quantum numbers of the structure are measured to be 3956±5±10 MeV, 43±13±8 MeV, and J^{PC}=0^{++}, respectively, where the first uncertainties are statistical and the second systematic. The properties of the new structure are consistent with recent theoretical predictions for a state composed of cc[over ¯]ss[over ¯] quarks. Evidence for an additional structure is found around 4140 MeV in the D_{s}^{+}D_{s}^{-} invariant mass, which might be caused either by a new resonance with the 0^{++} assignment or by a J/ψϕ↔D_{s}^{+}D_{s}^{-} coupled-channel effect.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Evidence for Modification of b Quark Hadronization in High-Multiplicity pp Collisions at sqrt[s]=13 TeV., Phys Rev Lett, Vol: 131
The production rate of B_{s}^{0} mesons relative to B^{0} mesons is measured by the LHCb experiment in pp collisions at a center-of-mass energy sqrt[s]=13 TeV over the forward rapidity interval 2<y<4.5 as a function of the charged particle multiplicity measured in the event. Evidence at the 3.4σ level is found for an increase of the ratio of B_{s}^{0} to B^{0} cross sections with multiplicity at transverse momenta below 6 GeV/c, with no significant multiplicity dependence at higher transverse momentum. Comparison with data from e^{+}e^{-} collisions implies that the density of the hadronic medium may affect the production rates of B mesons. This is qualitatively consistent with the emergence of quark coalescence as an additional hadronization mechanism in high-multiplicity collisions.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Search for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>C</mml:mi><mml:mi>P</mml:mi></mml:mrow></mml:math> violation using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mover accent="true"><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">^</mml:mo></mml:mrow></mml:mover></mml:mrow></mml:math>-odd correlations in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>B</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup><mml:mo stretchy="false">→</mml:mo><mml:mi>p</mml:mi><mml:mover accent="true"><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">¯</mml:mo></mml:mrow></mml:mover><mml:msup><mml:mrow><mml:mi>K</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>π</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math> decays, Physical Review D, Vol: 108, ISSN: 2470-0010
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Test of Lepton Universality in b→sℓ^{+}ℓ^{-} Decays., Phys Rev Lett, Vol: 131
The first simultaneous test of muon-electron universality using B^{+}→K^{+}ℓ^{+}ℓ^{-} and B^{0}→K^{*0}ℓ^{+}ℓ^{-} decays is performed, in two ranges of the dilepton invariant-mass squared, q^{2}. The analysis uses beauty mesons produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb^{-1}. Each of the four lepton universality measurements reported is either the first in the given q^{2} interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Multidifferential study of identified charged hadron distributions in Z -tagged jets in proton-proton collisions at s =13 TeV, Physical Review D, Vol: 108, ISSN: 2470-0010
Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a Z boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20<pT<100 GeV and in the pseudorapidity range 2.5<η<4. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb-1. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Study of charmonium decays to K S0 Kπ in the B → (K S0 Kπ)K channels, Physical Review D, Vol: 108, ISSN: 2470-0010
A study of the B+→KS0K+K-π+ and B+→KS0K+K+π- decays is performed using proton-proton collisions at center-of-mass energies of 7, 8 and 13 TeV at the LHCb experiment. The KS0Kπ invariant mass spectra from both decay modes reveal a rich content of charmonium resonances. New precise measurements of the ηc and ηc(2S) resonance parameters are performed and branching fraction measurements are obtained for B+ decays to ηc, J/ψ, ηc(2S) and χc1 resonances. In particular, the first observation and branching fraction measurement of B+→χc0K0π+ is reported as well as first measurements of the B+→K0K+K-π+ and B+→K0K+K+π- branching fractions. Dalitz plot analyses of ηc→KS0Kπ and ηc(2S)→KS0Kπ decays are performed. A new measurement of the amplitude and phase of the Kπ S-wave as functions of the Kπ mass is performed, together with measurements of the K0∗(1430), K0∗(1950) and a0(1700) parameters. Finally, the branching fractions of χc1 decays to K∗ resonances are also measured.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, First observation of the B+ → Ds+ Ds- K+ decay, Physical Review D, Vol: 108, ISSN: 2470-0010
The B+→Ds+Ds-K+ decay is observed for the first time using proton-proton collision data collected by the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb-1. Its branching fraction relative to that of the B+→D+D-K+ decay is measured to be B(B+→Ds+Ds-K+)B(B+→D+D-K+)=0.525±0.033±0.027±0.034, where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the Ds±→K∓K±π± and D±→K∓π±π± decays. This measurement fills an experimental gap in the knowledge of the family of Cabibbo-favored b¯→c¯cs¯ transitions and opens the path for unique studies of spectroscopy in future.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Search for K S (L)0 →μ+μ-μ+μ- decays at LHCb, Physical Review D, Vol: 108, ISSN: 2470-0010
A search for KS(L)0→μ+μ-μ+μ- 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(KS0→μ+μ-μ+μ-)<5.1×10-12 and B(KL0→μ+μ-μ+μ-)<2.3×10-9.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Erratum to: Open charm production and asymmetry in pNe collisions at (Formula presented.) (The European Physical Journal C, (2023), 83, 6, (541), 10.1140/epjc/s10052-023-11641-5), European Physical Journal C, Vol: 83, ISSN: 1434-6044
In this article footnote 38 was incorrectly listed as 38: Affiliated with an Institute Covered by a Cooperation Agreement with CERN, ICCUB, Universitat de Barcelona, Barcelona, Spain Two footnotes were merged into one. The correct footnotes should be: 38: Affiliated with an Institute Covered by a Cooperation Agreement with CERN 39: ICCUB, Universitat de Barcelona, Barcelona, Spain The original article has been corrected. The publisher apologizes for the inconvenience caused.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Nuclear Modification Factor of Neutral Pions in the Forward and Backward Regions in p-Pb Collisions., Phys Rev Lett, Vol: 131
The nuclear modification factor of neutral pions is measured in proton-lead collisions collected at a center-of-mass energy per nucleon of 8.16 TeV with the LHCb detector. The π^{0} production cross section is measured differentially in transverse momentum (p_{T}) for 1.5<p_{T}<10.0 GeV and in center-of-mass pseudorapidity (η_{c.m.}) regions 2.5<η_{c.m.}<3.5 (forward) and -4.0<η_{c.m.}<-3.0 (backward) defined relative to the proton beam direction. The forward measurement shows a sizable suppression of π^{0} production, while the backward measurement shows the first evidence of π^{0} enhancement in proton-lead collisions at the LHC. Together, these measurements provide precise constraints on models of nuclear structure and particle production in high-energy nuclear collisions.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Search for Rare Decays of D^{0} Mesons into Two Muons., Phys Rev Lett, Vol: 131
A search for the very rare D^{0}→μ^{+}μ^{-} decay is performed using data collected by the LHCb experiment in proton-proton collisions at sqrt[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}π^{+} 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}→μ^{+}μ^{-})<3.1×10^{-9} at a 90% C.L. This represents the world's most stringent limit, constraining models of physics beyond the standard model.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, First Observation of a Doubly Charged Tetraquark and Its Neutral Partner., Phys Rev Lett, Vol: 131
A combined amplitude analysis is performed for the decays B^{0}→D[over ¯]^{0}D_{s}^{+}π^{-} and B^{+}→D^{-}D_{s}^{+}π^{+}, 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±0.011±0.020 GeV and widths of 0.136±0.023±0.013 GeV are observed, which decay to D_{s}^{+}π^{+} and D_{s}^{+}π^{-} respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content [cs[over ¯]ud[over ¯]], and the latter state is a neutral tetraquark composed of [cs[over ¯]u[over ¯]d] quarks. Both states are found to have spin-parity of 0^{+}, and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Observation of sizeable <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>ω</mml:mi></mml:math> contribution to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>χ</mml:mi><mml:mrow><mml:mi>c</mml:mi><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo stretchy="false">(</mml:mo><mml:mn>3872</mml:mn><mml:mo stretchy="false">)</mml:mo><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>π</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup><mml:mi>J</mml:mi><mml:mo>/</mml:mo><mml:mi>ψ</mml:mi></mml:math> decays, Physical Review D, Vol: 108, ISSN: 2470-0010
Aaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023, Search for $$D^{*}(2007)^{0} \rightarrow \mu ^{+} \mu ^{-}$$ in $$B^{-}\rightarrow \pi ^{-} \mu ^{+} \mu ^{-}$$ decays, The European Physical Journal C, Vol: 83
<jats:title>Abstract</jats:title><jats:p>The very rare <jats:inline-formula><jats:alternatives><jats:tex-math>$${{D} ^*} (2007)^0\!\rightarrow {\mu ^+\mu ^-} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi>D</mml:mi> </mml:mrow> <mml:mo>∗</mml:mo> </mml:msup> <mml:msup> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>2007</mml:mn> <mml:mo>)</mml:mo> </mml:mrow> <mml:mn>0</mml:mn> </mml:msup> <mml:mspace /> <mml:mo>→</mml:mo> <mml:mrow> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>-</mml:mo> </mml:msup> </mml:mrow> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula> decay is searched for by analysing <jats:inline-formula><jats:alternatives><jats:tex-math>$${{{B} ^-}} \!\rightarrow {{\pi } ^-} {\mu ^+\mu ^-} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mrow>
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Observation of a J/ψΛ Resonance Consistent with a Strange Pentaquark Candidate in B^{-}→J/ψΛp[over ¯] Decays., Phys Rev Lett, Vol: 131
An amplitude analysis of B^{-}→J/ψΛp[over ¯] 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/ψΛ 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.
Albanese R, Alexandrov A, Alicante F, et al., 2023, Observation of Collider Muon Neutrinos with the SND@LHC Experiment., Phys Rev Lett, Vol: 131
We report the direct observation of muon neutrino interactions with the SND@LHC detector at the Large Hadron Collider. A dataset of proton-proton collisions at sqrt[s]=13.6 TeV collected by SND@LHC in 2022 is used, corresponding to an integrated luminosity of 36.8 fb^{-1}. The search is based on information from the active electronic components of the SND@LHC detector, which covers the pseudorapidity region of 7.2<η<8.4, inaccessible to the other experiments at the collider. Muon neutrino candidates are identified through their charged-current interaction topology, with a track propagating through the entire length of the muon detector. After selection cuts, 8 ν_{μ} interaction candidate events remain with an estimated background of 0.086 events, yielding a significance of about 7 standard deviations for the observed ν_{μ} signal.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Search for the baryon- and lepton-number violating decays B0 →pμ- and Bs0 →pμ, Physical Review D, Vol: 108, ISSN: 2470-0010
A search for the baryon- and lepton-number violating decays B0→pμ- and Bs0→pμ- is performed at the LHCb experiment using data collected in proton-proton collisions at s=7, 8 and 13 TeV, corresponding to integrated luminosities of 1, 2, and 6 fb-1, respectively. No significant signal for B0→pμ- and Bs0→pμ- decays is found and the upper limits on the branching fractions are determined to be B(B0→pμ-)<2.6(3.1)×10-9 and B(Bs0→pμ-)<12.1(14.0)×10-9, respectively, at 90% (95%) confidence level. These are the first limits on these decays to date.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Search for direct CP violation in charged charmless B →PV decays, Physical Review D, Vol: 108, ISSN: 2470-0010
Measurements of CP asymmetry in charmless B→PV decays are presented, where P and V denote a pseudoscalar and a vector meson, respectively. Five different B→PV decays from four final states, B±→π±π+π-, B±→K±π+π-, B±→K±K+K- and B±→π±K+K- are analyzed. The measurements are based on a method that does not require full amplitude analyses, and are performed using proton-proton collision data at a center-of-mass energy of 13 TeV collected by LHCb between 2015 and 2018, corresponding to an integrated luminosity of 5.9 fb-1. In the π+π- P-wave, in the region dominated by the B±→ρ(770)0K± decay, a CP asymmetry of ACP=+0.150±0.019±0.011 is measured, where the first uncertainty is statistical and the second is systematic. This is the first observation of CP violation in this process. For the other four decay channels, in regions dominated by the B±→ρ(770)0π±, B±→K(¯) ∗(892)0π±, B±→K(¯) ∗(892)0K± and B±→φ(1020)K± decays, CP asymmetries in the P-wave compatible with zero are measured.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Study of the B- → Λc+ Λ ¯ c- K- decay, Physical Review D, Vol: 108, ISSN: 2470-0010
The decay B-→Λc+Λ¯c-K- is studied in proton-proton collisions at a center-of-mass energy of s=13 TeV using data corresponding to an integrated luminosity of 5 fb-1 collected by the LHCb experiment. In the Λc+K- system, the Ξc(2930)0 state observed at the BABAR and Belle experiments is resolved into two narrower states, Ξc(2923)0 and Ξc(2939)0, whose masses and widths are measured to be m(Ξc(2923)0)=2924.5±0.4±1.1 MeV, m(Ξc(2939)0)=2938.5±0.9±2.3 MeV, Γ(Ξc(2923)0)=4.8±0.9±1.5 MeV, Γ(Ξc(2939)0)=11.0±1.9±7.5 MeV, where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt Λc+K- sample. Evidence of a new Ξc(2880)0 state is found with a local significance of 3.8σ, whose mass and width are measured to be 2881.8±3.1±8.5 MeV and 12.4±5.3±5.8 MeV, respectively. In addition, evidence of a new decay mode Ξc(2790)0→Λc+K- is found with a significance of 3.7σ. The relative branching fraction of B-→Λc+Λ¯c-K- with respect to the B-→D+D-K- decay is measured to be 2.36±0.11±0.22±0.25, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Amplitude analysis of B0 → D ¯ 0 Ds+ π- and B+ →D- Ds+ π+ decays, Physical Review D, Vol: 108, ISSN: 2470-0010
Resonant contributions in B0→D¯D0s+π- and B+→D-Ds+π+ 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 Dsπ decay channel.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Test of lepton flavor universality using B0 →D∗-τ+ντ decays with hadronic τ channels, Physical Review D, Vol: 108, ISSN: 2470-0010
The branching fraction B(B0→D∗-τ+ντ) is measured relative to that of the normalization mode B0→D∗-π+π-π+ using hadronic τ+→π+π-π+(π0)ν¯τ decays in proton-proton collision data at a center-of-mass energy of 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb-1. The measured ratio is B(B0→D∗-τ+ντ)/B(B0→D∗-π+π-π+)=1.70±0.10-0.10+0.11, where the first uncertainty is statistical and the second is related to systematic effects. Using established branching fractions for the B0→D∗-π+π-π+ and B0→D∗-μ+νμ modes, the lepton universality test R(D∗-)B(B0→D∗-τ+ντ)/B(B0→D∗-μ+νμ) is calculated, R(D∗-)=0.247±0.015±0.015±0.012, where the third uncertainty is due to the uncertainties on the external branching fractions. This result is consistent with the Standard Model prediction and with previous measurements.
Aaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023, J/ ψ and D production in √sNN=68.5GeV PbNe collisions, European Physical Journal C, Vol: 83, ISSN: 1434-6044
The first measurement of J/ ψ and D production in PbNe collisions by the LHCb experiment in its fixed-target configuration is reported. The production of J/ ψ and D mesons is studied with a beam of lead ions with an energy of 2.5 TeV per nucleon colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy of sNN=68.5GeV . The J/ ψ / D production cross-section ratio is studied as a function of rapidity, transverse momentum and collision centrality. These data are compared with measurements from pNe collisions at the same energy and show no difference in the observed J/ ψ suppression trend when comparing pNe and PbNe peripheral collisions with PbNe central collisions.
Aaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023, Erratum to: A study of CP violation in the decays B<sup>±</sup>→[K<sup>+</sup>K<sup>−</sup>π<sup>+</sup>π<sup>−</sup>]Dh<sup>±</sup>(h = K,π) and B<sup>±</sup>→[π<sup>+</sup>π<sup>−</sup>π<sup>+</sup>π<sup>−</sup>]Dh<sup>±</sup> (The European Physical Journal C, (2023), 83, 6, (547), 10.1140/epjc/s10052-023-11560-5), European Physical Journal C, Vol: 83, ISSN: 1434-6044
In the original article, the PDF version is missing Fig. 8. The correct Fig. 8 is shown here. (Figure presented.) Interpretation of the binned and phase-space (‘PS’) integrated measurements in terms to the underlying physics parameters. The (Formula presented.) and (Formula presented.) contours are shown, which correspond to (Formula presented.) ((Formula presented.)) and (Formula presented.) ((Formula presented.)) confidence intervals, respectively. Also shown is the result from the analysis of other decay modes at LHCb (‘LHCb 2021’) [21] The original article has been corrected. The publisher apologizes for the inconvenience caused.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Direct CP violation in charmless three-body decays of B± mesons, Physical Review D, Vol: 108, ISSN: 2470-0010
Measurements of CP asymmetries in charmless three-body decays of B± mesons are reported using proton-proton collision data collected by the LHCb detector, corresponding to an integrated luminosity of 5.9 fb-1. The previously observed CP asymmetry in B±→π±K+K- decays is confirmed, and CP asymmetries are observed with a significance of more than five standard deviations in the B±→π±π+π- and B±→K±K+K- decays, while the CP asymmetry of B±→K±π+π- decays is confirmed to be compatible with zero. The distributions of these asymmetries are also studied as a function of the three-body phase space and suggest contributions from rescattering and resonance interference processes. An indication of the presence of the decays B±→π±χc0(1P) in both B±→π±π+π- and B±→π±K+K- decays is observed, as is CP violation involving these amplitudes.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Search for the rare hadronic decay Bs0 →p p ¯, Physical Review D, Vol: 108, ISSN: 2470-0010
A search for the rare hadronic decay Bs0→pp¯ is performed using proton-proton collision data recorded by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb-1. No evidence of the decay is found and an upper limit on its branching fraction is set at B(Bs0→pp¯)<4.4(5.1)×10-9 at 90% (95%) confidence level; this is currently the world's best upper limit. The decay mode B0→pp¯ is measured with very large significance, confirming the first observation by the LHCb experiment in 2017. The branching fraction is determined to be B(B0→pp¯)=(1.27±0.15±0.05±0.04)×10-8, where the first uncertainty is statistical, the second is systematic and the third is due to the external branching fraction of the normalization channel B0→K+π-. The combination of the two LHCb measurements of the B0→pp¯ branching fraction yields B(B0→pp¯)=(1.27±0.13±0.05±0.03)×10-8.
Aaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023, Charmonium production in pNe collisions at √sNN=68.5 GeV, European Physical Journal C, Vol: 83, ISSN: 1434-6044
The measurement of charmonium states produced in proton-neon (pNe) collisions by the LHCb experiment in its fixed-target configuration is presented. The production of J/ψ and ψ(2 S) mesons is studied with a beam of 2.5 TeV protons colliding on gaseous neon targets at rest, corresponding to a nucleon-nucleon centre-of-mass energy sNN=68.5GeV . The data sample corresponds to an integrated luminosity of 21.7 ± 1.4 nb - 1 . The J/ψ and ψ(2 S) hadrons are reconstructed in μ+μ- final states. The J/ψ production cross-section per target nucleon in the centre-of-mass rapidity range y⋆∈ [- 2.29 , 0] is found to be 506±8±46nb/nucleon . The ratio of J/ψ and D cross-sections is evaluated to (1.06 ± 0.02 ± 0.09) % . The ψ(2 S) to J/ψ relative production rate is found to be (1.67 ± 0.27 ± 0.10) % in good agreement with other measurements involving beam and target nuclei of similar sizes.
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