Publications
1153 results found
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Observation of New Baryons in the Ξ_{b}^{-}π^{+}π^{-} and Ξ_{b}^{0}π^{+}π^{-} Systems., Phys Rev Lett, Vol: 131
The first observation and study of two new baryonic structures in the final state Ξ_{b}^{0}π^{+}π^{-} and the confirmation of the Ξ_{b}(6100)^{-} state in the Ξ_{b}^{-}π^{+}π^{-} 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 Ξ_{b}^{*0}, Ξ_{b}^{'-} and Ξ_{b}^{*-} resonances are measured with improved precision. The new decay mode of the Ξ_{b}^{0} baryon to the Ξ_{c}^{+} π^{-} π^{+} π^{-} final state is observed and exploited for the first time in these measurements.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Precision Measurement of CP Violation in the Penguin-Mediated Decay B_{s}^{0}→ϕϕ., Phys Rev Lett, Vol: 131
A flavor-tagged time-dependent angular analysis of the decay B_{s}^{0}→ϕϕ is performed using pp collision data collected by the LHCb experiment at the center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb^{-1}. The CP-violating phase and direct CP-violation parameter are measured to be ϕ_{s}^{ss[over ¯]s}=-0.042±0.075±0.009 rad and |λ|=1.004±0.030±0.009, respectively, assuming the same values for all polarization states of the ϕϕ 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 ϕ_{s}^{ss[over ¯]s}=-0.074±0.069 rad and |λ|=1.009±0.030. This is the most precise study of time-dependent CP violation in a penguin-dominated B meson decay. The results are consistent with CP symmetry and with the standard model predictions.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Evidence for the decays B0 → $$ \overline{D} $$(*)0ϕ and updated measurements of the branching fractions of the $$ {B}_s^0 $$ → $$ \overline{D} $$(*)0ϕ decays, Journal of High Energy Physics, Vol: 2023
<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>Evidence for the decays <jats:italic>B</jats:italic><jats:sup>0</jats:sup><jats:italic>→</jats:italic><jats:inline-formula><jats:alternatives><jats:tex-math>$$ \overline{D} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>D</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula><jats:sup>0</jats:sup><jats:italic>ϕ</jats:italic> and <jats:italic>B</jats:italic><jats:sup>0</jats:sup><jats:italic>→</jats:italic><jats:inline-formula><jats:alternatives><jats:tex-math>$$ \overline{D} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover> <mml:mi>D</mml:mi> <mml:mo>¯</mml:mo> </mml:mover> </mml:math></jats:alternatives></jats:inline-formula><jats:sup>*0</jats:sup><jats:italic>ϕ</jats:italic> is reported with a significance of 3.6 <jats:italic>σ</jats:italic> and 4.3 <jats:italic>σ</jats:italic>, respectively. The analysis employs <jats:italic>pp</jats:italic> collision data at centre-of-mass energies <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \sqrt{s} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt>
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Measurement of the Λ_{b}^{0}→Λ(1520)μ^{+}μ^{-} Differential Branching Fraction., Phys Rev Lett, Vol: 131
The branching fraction of the rare decay Λ_{b}^{0}→Λ(1520)μ^{+}μ^{-} is measured for the first time, in the squared dimuon mass intervals q^{2}, excluding the J/ψ and ψ(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 GeV^{2}/c^{4}, where theoretical predictions have the smallest model dependence, agrees with the predictions.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Observation of the decays B(s)0 → D<inf>s1</inf>(2536)<sup>∓</sup> K <sup> ±</sup>, Journal of High Energy Physics, Vol: 2023
This paper reports the observation of the decays B(s)0 → Ds1(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¯ 0 K + K −. The Ds1(2536) − meson is reconstructed in the D¯ *(2007)0 K − decay channel and the products of branching fractions are measured to be B(Bs0→Ds1(2536)∓K±)×B(Ds1(2536)−→D¯∗(2007)0K−)=(2.49±0.11±0.12±0.25±0.06)×10−5,B(B0→Ds1(2536)∓K±)×B(Ds1(2536)−→D¯∗(2007)0K−)=(0.510±0.021±0.036±0.050)×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¯ 0 K + K − normalisation channel. The last uncertainty in the Bs0 result is due to the limited knowledge of the fragmentation fraction ratio, fs/fd. The significance for the Bs0 and B 0 signals is larger than 10 σ. The ratio of the helicity amplitudes which governs the angular distribution of the Ds1(2536) − → D¯ *(2007)0 K − 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. [Figure not available: see fulltext.].
Aaij R, Beteta CA, Ackernley T, et al., 2023, Addendum: Test of lepton universality in beauty-quark decays, Nature Physics, Vol: 19, Pages: 1517-1517, ISSN: 1745-2473
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Evidence of a J/ψK_{S}^{0} Structure in B^{0}→J/ψϕK_{S}^{0} Decays., Phys Rev Lett, Vol: 131
An amplitude analysis of B^{0}→J/ψϕK_{S}^{0} 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/ψK_{S}^{0} system, named T_{ψs1}^{θ}(4000)^{0}, is seen, with its mass and width measured to be 3991_{-10}^{+12} _{-17}^{+9} MeV/c^{2} and 105_{-25}^{+29} _{-23}^{+17} MeV, respectively, where the first uncertainty is statistical and the second systematic. The T_{ψs1}^{θ}(4000)^{0} state is likely to be the isospin partner of the T_{ψs1}^{θ}(4000)^{+} state, previously observed in the J/ψK^{+} system of the B^{+}→J/ψϕK^{+} decay. When isospin symmetry for the charged and neutral T_{ψs1}^{θ}(4000) states is assumed, the signal significance increases to 5.4 standard deviations.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Observation of New Ω_{c}^{0} States Decaying to the Ξ_{c}^{+}K^{-} Final State., Phys Rev Lett, Vol: 131
Two new excited states, Ω_{c}(3185)^{0} and Ω_{c}(3327)^{0}, are observed in the Ξ_{c}^{+}K^{-} 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 Ω_{c}^{0} states are confirmed, namely Ω_{c}(3000)^{0}, Ω_{c}(3050)^{0}, Ω_{c}(3065)^{0}, Ω_{c}(3090)^{0}, and Ω_{c}(3119)^{0}. The masses and widths of these seven states are measured with the highest precision to date.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Measurement of CP asymmetries and branching fraction ratios of B− decays to two charm mesons, Journal of High Energy Physics, Vol: 2023
<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>The <jats:italic>CP</jats:italic> asymmetries of seven <jats:italic>B</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup> decays to two charm mesons are measured using data corresponding to an integrated luminosity of 9 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup> of proton-proton collisions collected by the LHCb experiment. Decays involving a <jats:italic>D</jats:italic><jats:sup>*0</jats:sup> or <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {D}_s^{\ast -} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mrow> <mml:mo>∗</mml:mo> <mml:mo>−</mml:mo> </mml:mrow> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> meson are analysed by reconstructing only the <jats:italic>D</jats:italic><jats:sup>0</jats:sup> or <jats:inline-formula><jats:alternatives><jats:tex-math>$$ {D}_s^{-} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>D</mml:mi> <mml:mi>s</mml:mi> <mml:mo>−</mml:mo> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> decay products. This paper presents the first measurement of <jats:inline-formula><ja
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Study of the Bose-Einstein correlations of same-sign pions in proton-lead collisions, Journal of High Energy Physics, Vol: 2023
<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>Correlations of same-sign charged pions are analysed using proton-lead collision data collected by the LHCb experiment at a nucleon-nucleon centre-of-mass energy of 5.02 TeV, corresponding to an integrated luminosity of 1.06 nb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. Bose-Einstein correlations are observed in the form of an enhancement of pair production for same-sign charged pions with a small four-momentum difference. The dependence of the correlation radius and the intercept parameter on the reconstructed charged-particle multiplicity is investigated. The measured correlation radii scale linearly with the cube root of the reconstructed charged-particle multiplicity, being compatible with predictions of hydrodynamic models on the collision system evolution.</jats:p>
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Search for CP violation in the phase space of D0 → π−π+π0 decays with the energy test, Journal of High Energy Physics, Vol: 2023
<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A search for <jats:italic>CP</jats:italic> violation in D<jats:sup>0</jats:sup> → <jats:italic>π</jats:italic><jats:sup><jats:italic>−</jats:italic></jats:sup><jats:italic>π</jats:italic><jats:sup>+</jats:sup><jats:italic>π</jats:italic><jats:sup>0</jats:sup> decays is reported, using <jats:italic>pp</jats:italic> collision data collected by the LHCb experiment from 2015 to 2018 corresponding to an integrated luminosity of 6 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. An unbinned model-independent approach provides sensitivity to local <jats:italic>CP</jats:italic> violation within the two-dimensional phase space of the decay. The method is validated using the Cabibbo-favoured channel D<jats:sup>0</jats:sup> → K<jats:sup><jats:italic>−</jats:italic></jats:sup><jats:italic>π</jats:italic><jats:sup>+</jats:sup><jats:italic>π</jats:italic><jats:sup>0</jats:sup> and background regions of the signal mode. The results are consistent with <jats:italic>CP</jats:italic> symmetry in this decay.</jats:p>
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Measurement of the Ratios of Branching Fractions R(D^{*}) and R(D^{0})., Phys Rev Lett, Vol: 131
The ratios of branching fractions R(D^{*})≡B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}μ^{-}ν[over ¯]_{μ}) and R(D^{0})≡B(B^{-}→D^{0}τ^{-}ν[over ¯]_{τ})/B(B^{-}→D^{0}μ^{-}ν[over ¯]_{μ}) 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 τ^{-}→μ^{-}ν_{τ}ν[over ¯]_{μ}. 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 ρ=-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.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Measurement of the Prompt D^{0} Nuclear Modification Factor in p-Pb Collisions at sqrt[s_{NN}]=8.16 TeV., Phys Rev Lett, Vol: 131
The production of prompt D^{0} mesons in proton-lead collisions in both the forward and backward rapidity regions at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=8.16 TeV is measured by the LHCb experiment. The nuclear modification factor of prompt D^{0} mesons is determined as a function of the transverse momentum p_{T}, and the rapidity in the nucleon-nucleon center-of-mass frame y^{*}. In the forward rapidity region, significantly suppressed production with respect to pp collisions is measured, which provides significant constraints on models of nuclear parton distributions and hadron production down to the very low Bjorken-x region of ∼10^{-5}. In the backward rapidity region, a suppression with a significance of 2.0-3.8 standard deviations compared to parton distribution functions in a nuclear environment expectations is found in the kinematic region of p_{T}>6 GeV/c and -3.25<y^{*}<-2.5, corresponding to x∼0.01.
Aaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023, Measurement of the mass difference and relative production rate of the ωb- and Ξb- baryons, Physical Review D, Vol: 108, ISSN: 2470-0010
The mass difference between the ωb- and Ξb- 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 m(ωb-)-m(Ξb-)=248.54±0.51(stat)±0.38(syst) MeV/c2. The mass of the ωb- baryon is measured to be m(ωb-)=6045.9±0.5(stat)±0.6(syst) MeV/c2. This is the most precise determination of the ωb- mass to date. In addition, the production rate of ωb- baryons relative to that of Ξb- 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<η<6 and pT<20 GeV/c with their decays to a J/ψ meson and a hyperon, the ratio fωb-fΞb-×B(ωb-→J/ψω-)B(Ξb-→J/ψΞ-)=0.120±0.008(stat)±0.008(syst), is obtained, where fωb- and fΞb- are the fragmentation fractions of b quarks into ωb- and Ξb- baryons, respectively, and B represents the branching fractions of their respective decays.
Aaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023, Model-independent measurement of charm mixing parameters in B ¯ →d0 (→ KS0 π+π-)μ- ν ¯ μx decays, Physical Review D, Vol: 108, ISSN: 2470-0010
A measurement of charm mixing and CP-violating parameters is reported, using B¯→D0(→KS0π+π-)μ-ν¯μX decays reconstructed in proton-proton collisions collected by the LHCb experiment during the years 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb-1. The measured mixing and CP-violating parameters are xCP=[4.29±1.48(stat)±0.26(syst)]×10-3, yCP=[12.61±3.12(stat)±0.83(syst)]×10-3, Δx=[-0.77±0.93(stat)±0.28(syst)]×10-3, Δy=[3.01±1.92(stat)±0.26(syst)]×10-3. The results are complementary to and consistent with previous measurements. A combination with the recent LHCb analysis of D∗+→D0(→KS0π+π-)π+ decays is reported.
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, Beteta CA, et al., 2023, Search for the doubly heavy baryon Ξ<inf>bc</inf><sup>+</sup> decaying to J/ψΞ<inf>c</inf><sup>+</sup> *, Chinese Physics C, Vol: 47, ISSN: 1674-1137
A first search for the Ξbc+ → J/ψΞc+ decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb−1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of 4.3(2.8) and 4.1(2.4) standard deviations at masses of 6571 and 6694 MeV/c2, respectively. Upper limits are set on the Ξbc+ baryon production cross-section times the branching fraction relative to that of the B+c → J/ψD+s decay at centre-of-mass energies of 8 and 13 TeV, in the Ξbc+ and in the B+c rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20 GeV/c, respectively. Upper limits are presented as a function of the Ξbc+ mass and lifetime.
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, Associated production of prompt J/ψ and Υ mesons in pp collisions at $$ \sqrt{s} $$ = 13 TeV, Journal of High Energy Physics, Vol: 2023
<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>The associated production of prompt <jats:italic>J/ψ</jats:italic> and <jats:italic>Υ</jats:italic> mesons in <jats:italic>pp</jats:italic> collisions at a centre-of-mass energy of <jats:inline-formula><jats:alternatives><jats:tex-math>$$ \sqrt{s} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math></jats:alternatives></jats:inline-formula> = 13 TeV is studied using LHCb data, corresponding to an integrated luminosity of 4 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. The measurement is performed for <jats:italic>J/ψ</jats:italic> (<jats:italic>Υ</jats:italic>) mesons with a transverse momentum <jats:italic>p</jats:italic><jats:sub>T</jats:sub><jats:italic><</jats:italic> 10 (30) GeV/<jats:italic>c</jats:italic> in the rapidity range 2<jats:italic>.</jats:italic>0 <jats:italic>< y <</jats:italic> 4<jats:italic>.</jats:italic>5. In this kinematic range, the cross-section of the associated production of prompt <jats:italic>J/ψ</jats:italic> and <jats:italic>Υ</jats:italic>(1<jats:italic>S</jats:italic>) mesons is measured to be 133 ± 22 ± 7 ± 3 pb, with a significance of 7<jats:italic>.</jats:italic>9 <jats:italic>σ</jats:italic>, and that of prompt <jats:italic>J/ψ</jats:italic> and <jats:italic>Υ</jats:italic>(2<jats:italic>S</jats:italic>) mesons to be 76 ±
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, 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, Search for CP violation using T ^ -odd correlations in B0 →p p ¯ K+π- decays, Physical Review D, Vol: 108, ISSN: 2470-0010
A search for CP and P violation in charmless four-body B0→pp¯K+π- decays is performed using triple-product asymmetry observables. It is based on proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8 and 13 TeV, corresponding to a total integrated luminosity of 8.4 fb-1. The CP- and P-violating asymmetries are measured both in the integrated phase space and in specific regions. No evidence is seen for CP violation. P-parity violation is observed at a significance of 5.8 standard deviations.
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, 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, 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, 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, Measurement of lepton universality parameters in B+ →k+ℓ+ℓ- and B0 →k∗0ℓ+ℓ- decays, Physical Review D, Vol: 108, ISSN: 2470-0010
A simultaneous analysis of the B+→K+ℓ+ℓ- and B0→K∗0ℓ+ℓ- decays is performed to test muon-electron 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.
Aaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023, Amplitude analysis of the ?<sub>c</sub><SUP>+</SUP>- pK-p<SUP>+</SUP> decay and ?<sub>c</sub><SUP>+</SUP> baryon polarization measurement in semileptonic beauty hadron decays, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010
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