Top Cited Papers
Open Access
Website
Google Scholar
Cited by 137
- 1 May 2024
- Published by IOP Publishing in Journal of Instrumentation
The LHCb Upgrade I
by R. Aaij, A.S.W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, C. Achard, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, et al.
The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software.
Website
Google Scholar
- 1 May 2024
- Published by IOP Publishing in Journal of Instrumentation
Top Cited Papers
Open Access
The LHCb Upgrade I
by R. Aaij, A.S.W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, C. Achard, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, et al.
The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software.
Cited by 137
Open Access
Website
Google Scholar
Cited by 12
- 1 April 2024
- Published by American Physical Society (APS) in Physical Review C
Measurement of $Ξ_{c}^{+}$ production in $p Pb$ collisions at $\sqrt{s_{N N}} = 8.16$ TeV at LHCb
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, C. Agapopoulou, et al.
A study of prompt $Ξ_{c}^{+}$ 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 $p Pb$ and $Pb p$ collisions with an estimated integrated luminosity of approximately 12.5 and 17.4 ${nb}^{- 1}$ , respectively. The $Ξ_{c}^{+}$ production cross section, as well as the $Ξ_{c}^{+}$ to $Λ_{c}^{+}$ 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 $Ξ_{c}^{+}$ transverse momentum. The results provide strong constraints on theoretical calculation and are a unique input for hadronization studies in different collision systems.
Website
Google Scholar
- 1 April 2024
- Published by American Physical Society (APS) in Physical Review C
Open Access
Measurement of $Ξ_{c}^{+}$ production in $p Pb$ collisions at $\sqrt{s_{N N}} = 8.16$ TeV at LHCb
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, C. Agapopoulou, et al.
A study of prompt $Ξ_{c}^{+}$ 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 $p Pb$ and $Pb p$ collisions with an estimated integrated luminosity of approximately 12.5 and 17.4 ${nb}^{- 1}$ , respectively. The $Ξ_{c}^{+}$ production cross section, as well as the $Ξ_{c}^{+}$ to $Λ_{c}^{+}$ 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 $Ξ_{c}^{+}$ transverse momentum. The results provide strong constraints on theoretical calculation and are a unique input for hadronization studies in different collision systems.
Cited by 12
Open Access
Website
Google Scholar
Cited by 14
- 6 September 2023
- Published by American Physical Society (APS) in Physical Review D
Model-independent measurement of charm mixing parameters in $\bar{B} \to D^{0} (\to K_{S}^{0} π^{+} π^{-}) μ^{-} {\bar{ν}}_{μ} X$ decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. Agapopoulou, C. A. Aidala, et al.
A measurement of charm mixing and $C P$ -violating parameters is reported, using $\bar{B} \to D^{0} (\to K_{S}^{0} π^{+} π^{-}) μ^{-} {\bar{ν}}_{μ} X$ 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 $C P$ -violating parameters are $x_{C P} = [4.29 \pm 1.48 (stat) \pm 0.26 (syst)] \times 10^{- 3}$ , $y_{C P} = [12.61 \pm 3.12 (stat) \pm 0.83 (syst)] \times 10^{- 3}$ , $Δ x = [- 0.77 \pm 0.93 (stat) \pm 0.28 (syst)] \times 10^{- 3}$ , $Δ y = [3.01 \pm 1.92 (stat) \pm 0.26 (syst)] \times 10^{- 3}$ . The results are complementary to and consistent with previous measurements. A combination with the recent LHCb analysis of $D^{* +} \to D^{0} (\to K_{S}^{0} π^{+} π^{-}) π^{+}$ decays is reported.
Website
Google Scholar
- 6 September 2023
- Published by American Physical Society (APS) in Physical Review D
Open Access
Model-independent measurement of charm mixing parameters in $\bar{B} \to D^{0} (\to K_{S}^{0} π^{+} π^{-}) μ^{-} {\bar{ν}}_{μ} X$ decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. Agapopoulou, C. A. Aidala, et al.
A measurement of charm mixing and $C P$ -violating parameters is reported, using $\bar{B} \to D^{0} (\to K_{S}^{0} π^{+} π^{-}) μ^{-} {\bar{ν}}_{μ} X$ 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 $C P$ -violating parameters are $x_{C P} = [4.29 \pm 1.48 (stat) \pm 0.26 (syst)] \times 10^{- 3}$ , $y_{C P} = [12.61 \pm 3.12 (stat) \pm 0.83 (syst)] \times 10^{- 3}$ , $Δ x = [- 0.77 \pm 0.93 (stat) \pm 0.28 (syst)] \times 10^{- 3}$ , $Δ y = [3.01 \pm 1.92 (stat) \pm 0.26 (syst)] \times 10^{- 3}$ . The results are complementary to and consistent with previous measurements. A combination with the recent LHCb analysis of $D^{* +} \to D^{0} (\to K_{S}^{0} π^{+} π^{-}) π^{+}$ decays is reported.
Cited by 14
Open Access
Website
Google Scholar
Cited by 2
- 29 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Measurement of the Branching Fractions $B (B^{0} \to p \bar{p} p \bar{p})$ and $B (B_{s}^{0} \to p \bar{p} p \bar{p})$
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, C. Agapopoulou, et al.
Website
Google Scholar
- 29 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Open Access
Measurement of the Branching Fractions $B (B^{0} \to p \bar{p} p \bar{p})$ and $B (B_{s}^{0} \to p \bar{p} p \bar{p})$
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, C. Agapopoulou, et al.
Cited by 2
Open Access
Website
Google Scholar
Cited by 79
- 29 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Measurement of the Time-Integrated $C P$ Asymmetry in $D^{0} \to K^{-} K^{+}$ Decays
by R Aaij, A Abdelmotteleb, C Abellan Beteta, F Abudinén, T Ackernley, B Adeva, M Adinolfi, P Adlarson, H Afsharnia, C Agapopoulou, et al.
The time-integrated $C P$ asymmetry in the Cabibbo-suppressed decay $D^{0} \to K^{-} K^{+}$ 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 $D^{* +} \to D^{0} π^{+}$ decays, and the charge of the companion pion is used to determine the flavor of the charm meson at production. The time-integrated $C P$ asymmetry is measured to be $A_{C P} (K^{-} K^{+}) = [6.8 \pm 5.4 \pm 1.6] \times 10^{- 4}$ where the first uncertainty is statistical and the second systematic. The direct $C P$ asymmetries in $D^{0} \to K^{-} K^{+}$ and $D^{0} \to π^{-} π^{+}$ decays, $a_{K^{-} K^{+}}^{d}$ and $a_{π^{-} π^{+}}^{d}$ , are derived by combining $A_{C P} (K^{-} K^{+})$ with the time-integrated $C P$ asymmetry difference, $Δ A_{C P} = A_{C P} (K^{-} K^{+}) - A_{C P} (π^{-} π^{+})$ , and other inputs, giving $a_{K^{-} K^{+}}^{d} = (7.7 \pm 5.7) \times 10^{- 4}, a_{π^{-} π^{+}}^{d} = (23.2 \pm 6.1) \times 10^{- 4},$ with a correlation coefficient corresponding to $ρ = 0.88$ . The compatibility of these results with $C P$ symmetry is 1.4 and 3.8 standard deviations for $D^{0} \to K^{-} K^{+}$ and $D^{0} \to π^{-} π^{+}$ decays, respectively. This is the first evidence for direct $C P$ violation in a specific $D^{0}$ decay.
Website
Google Scholar
- 29 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Open Access
Measurement of the Time-Integrated $C P$ Asymmetry in $D^{0} \to K^{-} K^{+}$ Decays
by R Aaij, A Abdelmotteleb, C Abellan Beteta, F Abudinén, T Ackernley, B Adeva, M Adinolfi, P Adlarson, H Afsharnia, C Agapopoulou, et al.
The time-integrated $C P$ asymmetry in the Cabibbo-suppressed decay $D^{0} \to K^{-} K^{+}$ 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 $D^{* +} \to D^{0} π^{+}$ decays, and the charge of the companion pion is used to determine the flavor of the charm meson at production. The time-integrated $C P$ asymmetry is measured to be $A_{C P} (K^{-} K^{+}) = [6.8 \pm 5.4 \pm 1.6] \times 10^{- 4}$ where the first uncertainty is statistical and the second systematic. The direct $C P$ asymmetries in $D^{0} \to K^{-} K^{+}$ and $D^{0} \to π^{-} π^{+}$ decays, $a_{K^{-} K^{+}}^{d}$ and $a_{π^{-} π^{+}}^{d}$ , are derived by combining $A_{C P} (K^{-} K^{+})$ with the time-integrated $C P$ asymmetry difference, $Δ A_{C P} = A_{C P} (K^{-} K^{+}) - A_{C P} (π^{-} π^{+})$ , and other inputs, giving $a_{K^{-} K^{+}}^{d} = (7.7 \pm 5.7) \times 10^{- 4}, a_{π^{-} π^{+}}^{d} = (23.2 \pm 6.1) \times 10^{- 4},$ with a correlation coefficient corresponding to $ρ = 0.88$ . The compatibility of these results with $C P$ symmetry is 1.4 and 3.8 standard deviations for $D^{0} \to K^{-} K^{+}$ and $D^{0} \to π^{-} π^{+}$ decays, respectively. This is the first evidence for direct $C P$ violation in a specific $D^{0}$ decay.
Cited by 79
Open Access
Website
Google Scholar
Cited by 66
- 14 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Observation of a Resonant Structure near the $D_{s}^{+} D_{s}^{-}$ Threshold in the $B^{+} \to D_{s}^{+} D_{s}^{-} K^{+}$ Decay
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. Agapopoulou, C. A. Aidala, et al.
Website
Google Scholar
- 14 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Open Access
Observation of a Resonant Structure near the $D_{s}^{+} D_{s}^{-}$ Threshold in the $B^{+} \to D_{s}^{+} D_{s}^{-} K^{+}$ Decay
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. Agapopoulou, C. A. Aidala, et al.
Cited by 66
Open Access
Website
Google Scholar
Cited by 16
- 14 August 2023
- Published by American Physical Society (APS) in Physical Review D
First observation of the $B^{+} \to D_{s}^{+} D_{s}^{-} K^{+}$ decay
by R Aaij, A Abdelmotteleb, C Abellan Beteta, F Abudinén, T Ackernley, B Adeva, M Adinolfi, H Afsharnia, C Agapopoulou, C Aidala, et al.
The $B^{+} \to D_{s}^{+} D_{s}^{-} K^{+}$ 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 $B^{+} \to D^{+} D^{-} K^{+}$ decay is measured to be $\frac{B (B^{+} \to D_{s}^{+} D_{s}^{-} K^{+})}{B (B^{+} \to D^{+} D^{-} K^{+})} = 0.525 \pm 0.033 \pm 0.027 \pm 0.034,$ where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the $D_{s}^{\pm} \to K^{\mp} K^{\pm} π^{\pm}$ and $D^{\pm} \to K^{\mp} π^{\pm} π^{\pm}$ decays. This measurement fills an experimental gap in the knowledge of the family of Cabibbo-favored $\bar{b} \to \bar{c} c \bar{s}$ transitions and opens the path for unique studies of spectroscopy in future.
Website
Google Scholar
- 14 August 2023
- Published by American Physical Society (APS) in Physical Review D
Open Access
First observation of the $B^{+} \to D_{s}^{+} D_{s}^{-} K^{+}$ decay
by R Aaij, A Abdelmotteleb, C Abellan Beteta, F Abudinén, T Ackernley, B Adeva, M Adinolfi, H Afsharnia, C Agapopoulou, C Aidala, et al.
The $B^{+} \to D_{s}^{+} D_{s}^{-} K^{+}$ 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 $B^{+} \to D^{+} D^{-} K^{+}$ decay is measured to be $\frac{B (B^{+} \to D_{s}^{+} D_{s}^{-} K^{+})}{B (B^{+} \to D^{+} D^{-} K^{+})} = 0.525 \pm 0.033 \pm 0.027 \pm 0.034,$ where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the $D_{s}^{\pm} \to K^{\mp} K^{\pm} π^{\pm}$ and $D^{\pm} \to K^{\mp} π^{\pm} π^{\pm}$ decays. This measurement fills an experimental gap in the knowledge of the family of Cabibbo-favored $\bar{b} \to \bar{c} c \bar{s}$ transitions and opens the path for unique studies of spectroscopy in future.
Cited by 16
Open Access
Website
Google Scholar
Cited by 23
- 10 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Evidence for Modification of $b$ Quark Hadronization in High-Multiplicity $p p$ Collisions at $\sqrt{s} = 13 TeV$
by R Aaij, A Abdelmotteleb, C Abellan Beteta, F Abudinén, T Ackernley, B Adeva, M Adinolfi, H Afsharnia, C Agapopoulou, C Aidala, et al.
The production rate of $B_{s}^{0}$ mesons relative to $B^{0}$ mesons is measured by the LHCb experiment in $p p$ 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 $3.4 σ$ 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.
Website
Google Scholar
- 10 August 2023
- Published by American Physical Society (APS) in Physical Review Letters
Open Access
Evidence for Modification of $b$ Quark Hadronization in High-Multiplicity $p p$ Collisions at $\sqrt{s} = 13 TeV$
by R Aaij, A Abdelmotteleb, C Abellan Beteta, F Abudinén, T Ackernley, B Adeva, M Adinolfi, H Afsharnia, C Agapopoulou, C Aidala, et al.
The production rate of $B_{s}^{0}$ mesons relative to $B^{0}$ mesons is measured by the LHCb experiment in $p p$ 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 $3.4 σ$ 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.
Cited by 23
Open Access
Website
Google Scholar
Cited by 3
- 8 August 2023
- Published by American Physical Society (APS) in Physical Review D
Search for $C P$ violation using $\hat{T}$ -odd correlations in $B^{0} \to p \bar{p} K^{+} π^{-}$ decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. Agapopoulou, C. A. Aidala, et al.
A search for $C P$ and $P$ violation in charmless four-body $B^{0} \to p \bar{p} K^{+} π^{-}$ 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 $C P$ - and $P$ -violating asymmetries are measured both in the integrated phase space and in specific regions. No evidence is seen for $C P$ violation. $P$ -parity violation is observed at a significance of 5.8 standard deviations.
Website
Google Scholar
- 8 August 2023
- Published by American Physical Society (APS) in Physical Review D
Open Access
Search for $C P$ violation using $\hat{T}$ -odd correlations in $B^{0} \to p \bar{p} K^{+} π^{-}$ decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. Agapopoulou, C. A. Aidala, et al.
A search for $C P$ and $P$ violation in charmless four-body $B^{0} \to p \bar{p} K^{+} π^{-}$ 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 $C P$ - and $P$ -violating asymmetries are measured both in the integrated phase space and in specific regions. No evidence is seen for $C P$ violation. $P$ -parity violation is observed at a significance of 5.8 standard deviations.
Cited by 3
Open Access
Website
Google Scholar
Cited by 2
- 8 August 2023
- Published by Springer Nature in The European Physical Journal C
Publisher Erratum: Open charm production and asymmetry in pNe collisions at $\sqrt{s_{\scriptscriptstyle {\text {NN}}}} = 68.5$ GeV
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, C. Agapopoulou, et al.
Website
Google Scholar
- 8 August 2023
- Published by Springer Nature in The European Physical Journal C
Open Access
Publisher Erratum: Open charm production and asymmetry in pNe collisions at $\sqrt{s_{\scriptscriptstyle {\text {NN}}}} = 68.5$ GeV
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, P. Adlarson, H. Afsharnia, C. Agapopoulou, et al.
Cited by 2

Show all