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- 26 October 2026
- Published by Springer Nature in Journal of High Energy Physics
Search for CP violation in D+ → ϕπ+ decays
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: A search for charge-parity ( CP ) violation in the Cabibbo-suppressed D ⁺ → ϕπ ⁺ decay is presented, using proton-proton collision data corresponding to an integrated luminosity of 6 fb ^{−
1} , collected at a centre-of-mass energy of 13 TeV with the LHCb detector during Run 2. An abundant sample of $$ {D}^{+}\to {K}_{\mathrm{S}}^0{\pi}^{+} $$ $D^{+} \to K_{S}^{0} π^{+}$ decays is employed to correct for asymmetries arising from the production of the charmed meson and from detection effects associated with the charged pion accompanying the ϕ meson. Asymmetries induced by interference of multiple processes, such as neutral kaon mixing, regeneration of neutral kaons, and interference between the Cabibbo-favoured $$ {D}^{+}\to {\overline{K}}^0{\pi}^{+} $$ $D^{+} \to {\bar{K}}^{0} π^{+}$ and the doubly Cabibbo-suppressed D ⁺ → K ⁰ π ⁺ decay, are subtracted. The direct CP asymmetry in the D ⁺ → ϕπ ⁺ decay is measured to be $$ {a}_{CP}\left({D}^{+}\to \phi {\pi}^{+}\right)=\left(0.1\pm 4.9\left(\mathrm{stat}\right)\pm 2.4\left(\mathrm{syst}\right)\right)\times {10}^{-4}. $$ $a_{CP} (D^{+} \to ϕ π^{+}) = (0.1 \pm 4.9 (stat) \pm 2.4 (syst)) \times 10^{- 4} .$ For the first time at a hadron collider, the modulus of the ratio and the relative strong phase of the D ⁺ → K ⁰ π ⁺ to $$ {D}^{+}\to {\overline{K}}^0{\pi}^{+} $$ $D^{+} \to {\bar{K}}^{0} π^{+}$ decay amplitudes are also investigated. Two-dimensional confidence intervals are reported for these parameters.
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- 26 October 2026
- Published by Springer Nature in Journal of High Energy Physics
Open Access
Search for CP violation in D+ → ϕπ+ decays
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: A search for charge-parity ( CP ) violation in the Cabibbo-suppressed D ⁺ → ϕπ ⁺ decay is presented, using proton-proton collision data corresponding to an integrated luminosity of 6 fb ^{−
1} , collected at a centre-of-mass energy of 13 TeV with the LHCb detector during Run 2. An abundant sample of $$ {D}^{+}\to {K}_{\mathrm{S}}^0{\pi}^{+} $$ $D^{+} \to K_{S}^{0} π^{+}$ decays is employed to correct for asymmetries arising from the production of the charmed meson and from detection effects associated with the charged pion accompanying the ϕ meson. Asymmetries induced by interference of multiple processes, such as neutral kaon mixing, regeneration of neutral kaons, and interference between the Cabibbo-favoured $$ {D}^{+}\to {\overline{K}}^0{\pi}^{+} $$ $D^{+} \to {\bar{K}}^{0} π^{+}$ and the doubly Cabibbo-suppressed D ⁺ → K ⁰ π ⁺ decay, are subtracted. The direct CP asymmetry in the D ⁺ → ϕπ ⁺ decay is measured to be $$ {a}_{CP}\left({D}^{+}\to \phi {\pi}^{+}\right)=\left(0.1\pm 4.9\left(\mathrm{stat}\right)\pm 2.4\left(\mathrm{syst}\right)\right)\times {10}^{-4}. $$ $a_{CP} (D^{+} \to ϕ π^{+}) = (0.1 \pm 4.9 (stat) \pm 2.4 (syst)) \times 10^{- 4} .$ For the first time at a hadron collider, the modulus of the ratio and the relative strong phase of the D ⁺ → K ⁰ π ⁺ to $$ {D}^{+}\to {\overline{K}}^0{\pi}^{+} $$ $D^{+} \to {\bar{K}}^{0} π^{+}$ decay amplitudes are also investigated. Two-dimensional confidence intervals are reported for these parameters.
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- 5 October 2026
- Published by Springer Nature in Journal of High Energy Physics
Evidence for the decay $ {B}_s^0\to {\phi \eta}^{\prime } $
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: Using a dataset corresponding to an integrated luminosity of 9 fb ^{−
1} collected in proton-proton collisions between 2011 and 2018 by the LHCb experiment, evidence is found for the decay $$ {B}_s^0\to {\phi \eta}^{\prime } $$ $B_{s}^{0} \to {ϕη}^{'}$ with 3 . 5 σ significance. The branching ratio relative to the $$ {B}_s^0\to \phi \phi $$ $B_{s}^{0} \to ϕϕ$ decay is determined to be ℛ = (3 . 56 ± 0 . 79 ± 0 . 18 ± 0 . 06) × 10 ^{−
2} . This corresponds to a branching fraction, $$ \mathcal{B}\left({B}_s^0\to {\phi \eta}^{\prime}\right)=\left(0.66\pm 0.15\pm 0.03\pm 0.02\right)\times {10}^{-6} $$ $B (B_{s}^{0} \to {ϕη}^{'}) = (0.66 \pm 0.15 \pm 0.03 \pm 0.02) \times 10^{- 6}$ where, in both cases, the first uncertainty is statistical, the second systematic, and the third due to external branching fractions.
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- 5 October 2026
- Published by Springer Nature in Journal of High Energy Physics
Open Access
Evidence for the decay $ {B}_s^0\to {\phi \eta}^{\prime } $
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: Using a dataset corresponding to an integrated luminosity of 9 fb ^{−
1} collected in proton-proton collisions between 2011 and 2018 by the LHCb experiment, evidence is found for the decay $$ {B}_s^0\to {\phi \eta}^{\prime } $$ $B_{s}^{0} \to {ϕη}^{'}$ with 3 . 5 σ significance. The branching ratio relative to the $$ {B}_s^0\to \phi \phi $$ $B_{s}^{0} \to ϕϕ$ decay is determined to be ℛ = (3 . 56 ± 0 . 79 ± 0 . 18 ± 0 . 06) × 10 ^{−
2} . This corresponds to a branching fraction, $$ \mathcal{B}\left({B}_s^0\to {\phi \eta}^{\prime}\right)=\left(0.66\pm 0.15\pm 0.03\pm 0.02\right)\times {10}^{-6} $$ $B (B_{s}^{0} \to {ϕη}^{'}) = (0.66 \pm 0.15 \pm 0.03 \pm 0.02) \times 10^{- 6}$ where, in both cases, the first uncertainty is statistical, the second systematic, and the third due to external branching fractions.
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- 4 September 2026
- Published by Springer Nature in Journal of High Energy Physics
Search for τ− → μ−μ+μ− decays at the LHCb experiment with Run 2 data
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: A search for the lepton-flavour-violating decay τ ⁻ → μ ⁻ μ ⁺ μ ⁻ is carried out using data collected by the LHCb experiment between 2016 and 2018 in proton-proton collisions at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb ^{−
1} . An upper limit of 1 . 9 (2 . 3) × 10 ^{−
8} is set at the 90% (95%) confidence level on the branching fraction of the decay.
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- 4 September 2026
- Published by Springer Nature in Journal of High Energy Physics
Open Access
Search for τ− → μ−μ+μ− decays at the LHCb experiment with Run 2 data
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: A search for the lepton-flavour-violating decay τ ⁻ → μ ⁻ μ ⁺ μ ⁻ is carried out using data collected by the LHCb experiment between 2016 and 2018 in proton-proton collisions at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb ^{−
1} . An upper limit of 1 . 9 (2 . 3) × 10 ^{−
8} is set at the 90% (95%) confidence level on the branching fraction of the decay.
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- 19 August 2026
- Published by Springer Nature in Journal of High Energy Physics
Measurement of the local and nonlocal amplitudes in B+ → K+μ+μ− decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: This paper presents a thorough study of the local and nonlocal amplitudes in B ⁺ → K ⁺ μ ⁺ μ ⁻ transitions through an amplitude analysis of the dimuon mass spectrum of the decay. The analysis is based on pp collision data corresponding to an integrated luminosity of 8.4 fb ^{−
1} collected by the LHCb experiment during Run1 and Run2. This measurement employs a model that describes both one-particle and two-particle nonlocal amplitudes across the entirety of the dimuon mass spectrum, enabling the determination of both short- and long-distance contributions to the decay. The compatibility of the Wilson coefficient combinations $$ {C}_9+{C}_9^{\prime } $$ $C_{9} + C_{9}^{'}$ and $$ {C}_{10}+{C}_{10}^{\prime } $$ $C_{10} + C_{10}^{'}$ with the Standard Model prediction is found to vary between 1 . 6 σ and 4 σ , depending on the choice of local form factors.
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- 19 August 2026
- Published by Springer Nature in Journal of High Energy Physics
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Measurement of the local and nonlocal amplitudes in B+ → K+μ+μ− decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: This paper presents a thorough study of the local and nonlocal amplitudes in B ⁺ → K ⁺ μ ⁺ μ ⁻ transitions through an amplitude analysis of the dimuon mass spectrum of the decay. The analysis is based on pp collision data corresponding to an integrated luminosity of 8.4 fb ^{−
1} collected by the LHCb experiment during Run1 and Run2. This measurement employs a model that describes both one-particle and two-particle nonlocal amplitudes across the entirety of the dimuon mass spectrum, enabling the determination of both short- and long-distance contributions to the decay. The compatibility of the Wilson coefficient combinations $$ {C}_9+{C}_9^{\prime } $$ $C_{9} + C_{9}^{'}$ and $$ {C}_{10}+{C}_{10}^{\prime } $$ $C_{10} + C_{10}^{'}$ with the Standard Model prediction is found to vary between 1 . 6 σ and 4 σ , depending on the choice of local form factors.
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- 6 August 2026
- Published by Springer Nature in Journal of High Energy Physics
Measurement of CP asymmetries in $ {\overline{B}}^0\to {D}_s^{-}{D}^{+} $ and $ {\overline{B}}_s^0\to {D}_s^{-}{D}^{-} $ decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: Measurements of the combined CP asymmetries in $$ {\overline{B}}^0\to {D}_s^{-}{D}^{+} $$ ${\bar{B}}^{0} \to D_{s}^{-} D^{+}$ and $$ {\overline{B}}_s^0\to {D}_s^{-}{D}^{-} $$ ${\bar{B}}_{s}^{0} \to D_{s}^{-} D^{-}$ decays are made using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb ^{−
1} . The measurements are found to be $$ {\displaystyle \begin{array}{l}{A}_{CP}\left({\overline{B}}^0\to {D}_s^{-}{D}^{+}\right)=0.0009\pm 0.0053\pm 0.0040,\\ {}{A}_{CP}\left({\overline{B}}_s^0\to {D}_s^{-}{D}^{-}\right)=0.103\pm 0.053\pm 0.010,\end{array}} $$ $\begin{matrix} A_{CP} ({\bar{B}}^{0} \to D_{s}^{-} D^{+}) = 0.0009 \pm 0.0053 \pm 0.0040, \\ A_{CP} ({\bar{B}}_{s}^{0} \to D_{s}^{-} D^{-}) = 0.103 \pm 0.053 \pm 0.010, \end{matrix}$ where the first and second uncertainties are statistical and systematic, respectively. This is the first measurement of this asymmetry in $$ {\overline{B}}_s^0 $$ ${\bar{B}}_{s}^{0}$ decays, and the most precise measurement to date for $$ {\overline{B}}^0 $$ ${\bar{B}}^{0}$ decays. Both measurements are found to be consistent with CP symmetry.
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- 6 August 2026
- Published by Springer Nature in Journal of High Energy Physics
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Measurement of CP asymmetries in $ {\overline{B}}^0\to {D}_s^{-}{D}^{+} $ and $ {\overline{B}}_s^0\to {D}_s^{-}{D}^{-} $ decays
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: Measurements of the combined CP asymmetries in $$ {\overline{B}}^0\to {D}_s^{-}{D}^{+} $$ ${\bar{B}}^{0} \to D_{s}^{-} D^{+}$ and $$ {\overline{B}}_s^0\to {D}_s^{-}{D}^{-} $$ ${\bar{B}}_{s}^{0} \to D_{s}^{-} D^{-}$ decays are made using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb ^{−
1} . The measurements are found to be $$ {\displaystyle \begin{array}{l}{A}_{CP}\left({\overline{B}}^0\to {D}_s^{-}{D}^{+}\right)=0.0009\pm 0.0053\pm 0.0040,\\ {}{A}_{CP}\left({\overline{B}}_s^0\to {D}_s^{-}{D}^{-}\right)=0.103\pm 0.053\pm 0.010,\end{array}} $$ $\begin{matrix} A_{CP} ({\bar{B}}^{0} \to D_{s}^{-} D^{+}) = 0.0009 \pm 0.0053 \pm 0.0040, \\ A_{CP} ({\bar{B}}_{s}^{0} \to D_{s}^{-} D^{-}) = 0.103 \pm 0.053 \pm 0.010, \end{matrix}$ where the first and second uncertainties are statistical and systematic, respectively. This is the first measurement of this asymmetry in $$ {\overline{B}}_s^0 $$ ${\bar{B}}_{s}^{0}$ decays, and the most precise measurement to date for $$ {\overline{B}}^0 $$ ${\bar{B}}^{0}$ decays. Both measurements are found to be consistent with CP symmetry.
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- 5 August 2026
- Published by Springer Nature in Journal of High Energy Physics
Observation of the charmless purely baryonic decay $ {\Lambda}_b^0\to \Lambda p\overline{p} $
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: A search for the charmless purely baryonic decay $$ {\Lambda}_b^0\to \Lambda p\overline{p} $$ $Λ_{b}^{0} \to Λ p \bar{p}$ is performed using proton-proton collision data recorded by the LHCb experiment at a centre-of-mass energy of $$ \sqrt{s}=13 $$ $\sqrt{s} = 13$ TeV and corresponding to an integrated luminosity of 6 . 0 fb ^{−
1} . The signal decay is observed with a significance of 5.1 standard deviations. Its branching fraction is measured for the first time, relative to that of the topologically similar decay $$ {\Lambda}_b^0\to \Lambda {K}^{+}{K}^{-} $$ $Λ_{b}^{0} \to Λ K^{+} K^{-}$ . Contributions from intermediate charmonium resonances decaying to the $$ p\overline{p} $$ $p \bar{p}$ and K ⁺ K ⁻ final states are explicitly excluded with a requirement on the invariant mass of the companion hadron system, $$ m\left(h\overline{h}\right)<2.85 $$ $m (h \bar{h}) < 2.85$ GeV, where h stands for a proton or a charged kaon. The relative branching fraction is found to be $$ \frac{\mathcal{B}\left({\Lambda}_b^0\to \Lambda p\overline{p}\right)}{\mathcal{B}\left({\Lambda}_b^0\to \Lambda {K}^{+}{K}^{-}\right)}=\left(5.1\pm {1.3}_{\left(\mathrm{stat}\right)}\pm {0.3}_{\left(\mathrm{syst}\right)}\right)\times {10}^{-2}. $$ $\frac{B (Λ_{b}^{0} \to Λ p \bar{p})}{B (Λ_{b}^{0} \to Λ K^{+} K^{-})} = (5.1 \pm {1.3}_{(stat)} \pm {0.3}_{(syst)}) \times 10^{- 2} .$
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- 5 August 2026
- Published by Springer Nature in Journal of High Energy Physics
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Observation of the charmless purely baryonic decay $ {\Lambda}_b^0\to \Lambda p\overline{p} $
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: A search for the charmless purely baryonic decay $$ {\Lambda}_b^0\to \Lambda p\overline{p} $$ $Λ_{b}^{0} \to Λ p \bar{p}$ is performed using proton-proton collision data recorded by the LHCb experiment at a centre-of-mass energy of $$ \sqrt{s}=13 $$ $\sqrt{s} = 13$ TeV and corresponding to an integrated luminosity of 6 . 0 fb ^{−
1} . The signal decay is observed with a significance of 5.1 standard deviations. Its branching fraction is measured for the first time, relative to that of the topologically similar decay $$ {\Lambda}_b^0\to \Lambda {K}^{+}{K}^{-} $$ $Λ_{b}^{0} \to Λ K^{+} K^{-}$ . Contributions from intermediate charmonium resonances decaying to the $$ p\overline{p} $$ $p \bar{p}$ and K ⁺ K ⁻ final states are explicitly excluded with a requirement on the invariant mass of the companion hadron system, $$ m\left(h\overline{h}\right)<2.85 $$ $m (h \bar{h}) < 2.85$ GeV, where h stands for a proton or a charged kaon. The relative branching fraction is found to be $$ \frac{\mathcal{B}\left({\Lambda}_b^0\to \Lambda p\overline{p}\right)}{\mathcal{B}\left({\Lambda}_b^0\to \Lambda {K}^{+}{K}^{-}\right)}=\left(5.1\pm {1.3}_{\left(\mathrm{stat}\right)}\pm {0.3}_{\left(\mathrm{syst}\right)}\right)\times {10}^{-2}. $$ $\frac{B (Λ_{b}^{0} \to Λ p \bar{p})}{B (Λ_{b}^{0} \to Λ K^{+} K^{-})} = (5.1 \pm {1.3}_{(stat)} \pm {0.3}_{(syst)}) \times 10^{- 2} .$
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- 5 August 2026
- Published by Springer Nature in Journal of High Energy Physics
Measurement of γ using B± → DK± and B± → Dπ± decays with $ D\to {K}_{\mathrm{S}}^0{\pi}^{+}{\pi}^{-} $ and $ D\to {K}_{\mathrm{S}}^0{K}^{+}{K}^{-} $
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: A measurement of the CKM angle γ using the decay channels B ^± → DK ^± and B ^± → Dπ ^± , where the D meson decays to $$ D\to {K}_{\mathrm{S}}^0{\pi}^{+}{\pi}^{-} $$ $D \to K_{S}^{0} π^{+} π^{-}$ or $$ D\to {K}_{\mathrm{S}}^0{K}^{+}{K}^{-} $$ $D \to K_{S}^{0} K^{+} K^{-}$ , is performed with a data sample corresponding to an integrated luminosity of 5.8 fb ^{−
1} , collected during 2024 by the upgraded LHCb experiment. CP violation is observed through a difference in the distributions of the Dalitz plot of the D decay between the B ⁺ and B ⁻ mesons. The CKM angle γ is determined to be γ = (68 . 1 ± 6 . 7) ° . Other parameters related to the examined B meson decay modes are also measured. This is the first measurement of the CKM angle γ using the upgraded LHCb detector.
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- 5 August 2026
- Published by Springer Nature in Journal of High Energy Physics
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Measurement of γ using B± → DK± and B± → Dπ± decays with $ D\to {K}_{\mathrm{S}}^0{\pi}^{+}{\pi}^{-} $ and $ D\to {K}_{\mathrm{S}}^0{K}^{+}{K}^{-} $
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: A measurement of the CKM angle γ using the decay channels B ^± → DK ^± and B ^± → Dπ ^± , where the D meson decays to $$ D\to {K}_{\mathrm{S}}^0{\pi}^{+}{\pi}^{-} $$ $D \to K_{S}^{0} π^{+} π^{-}$ or $$ D\to {K}_{\mathrm{S}}^0{K}^{+}{K}^{-} $$ $D \to K_{S}^{0} K^{+} K^{-}$ , is performed with a data sample corresponding to an integrated luminosity of 5.8 fb ^{−
1} , collected during 2024 by the upgraded LHCb experiment. CP violation is observed through a difference in the distributions of the Dalitz plot of the D decay between the B ⁺ and B ⁻ mesons. The CKM angle γ is determined to be γ = (68 . 1 ± 6 . 7) ° . Other parameters related to the examined B meson decay modes are also measured. This is the first measurement of the CKM angle γ using the upgraded LHCb detector.
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- 3 August 2026
- Published by Springer Nature in Journal of High Energy Physics
Angular analysis of the B+ → π+μ+μ− decay
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: This paper presents the first measurement of the forward-backward asymmetry, A _FB , and the flat term, F _H , that parameterise the angular distribution of the B ⁺ → π ⁺ μ ⁺ μ ⁻ decay. The proton-proton collision dataset used in the analysis corresponds to an integrated luminosity of 9 fb ^{−
1} , collected with the LHCb experiment between 2011 and 2018. The analysis is performed in two intervals of dimuon mass squared, one above and one below the region containing the J/ψ and ψ (2 S ) narrow charmonium resonances. The Standard Model predictions lie within the obtained 68% confidence level interval in the high-mass and within the 99% interval in the low-mass region.
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- 3 August 2026
- Published by Springer Nature in Journal of High Energy Physics
Open Access
Angular analysis of the B+ → π+μ+μ− decay
by R. Aaij, M. Abdelfatah, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, et al.
A bstract: This paper presents the first measurement of the forward-backward asymmetry, A _FB , and the flat term, F _H , that parameterise the angular distribution of the B ⁺ → π ⁺ μ ⁺ μ ⁻ decay. The proton-proton collision dataset used in the analysis corresponds to an integrated luminosity of 9 fb ^{−
1} , collected with the LHCb experiment between 2011 and 2018. The analysis is performed in two intervals of dimuon mass squared, one above and one below the region containing the J/ψ and ψ (2 S ) narrow charmonium resonances. The Standard Model predictions lie within the obtained 68% confidence level interval in the high-mass and within the 99% interval in the low-mass region.
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- 1 August 2026
- Published by IOP Publishing in Journal of Instrumentation
Photon detection using 3D sensors with geometrical gain: the OPTIME 3D silicon sensor
by A. Loi, M. Boscardin, A. Cardini, A. Contu, G.M. Cossu, G.-F. Dalla Betta, A. Lai, A. Lampis, F. Mattedi, Sabina Ronchin, et al.
Within the INFN OpTiME project, we present the latest characterization results of a novel 3D silicon sensor developed as a core component of a multistage photo-detector system for fast timing with resolutions below the ps threshold. The presented device is based on FBK double-sided 3D silicon technology and is optimized for low-energy electrons and photon detection. Extensive electrical and functional tests have been performed to assess its performance, including studies of its charge collection and time response using Transient Current Technique (TCT). The results from the characterisation campaign show an intrinsic time resolution below 1 ps, displayed during TCT scan as well as the presence of a stable intrinsic charge gain without the need for a dedicated gain layer up to a factor of 10 at 200 V bias voltage, indicating the potential for radiation-tolerant silicon sensors with internal amplification. While its primary application is in fast-timing detectors, we also explore its suitability as a compact, high-resolution photosensor. Such versatility could enable its use in fields requiring precise timing, such as at pulsed fs X-ray facilities. In this work we will present the overall characterisation of the device, its performances after TCT scan and show its future applications as a fast-timing sensor.
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- 1 August 2026
- Published by IOP Publishing in Journal of Instrumentation
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Photon detection using 3D sensors with geometrical gain: the OPTIME 3D silicon sensor
by A. Loi, M. Boscardin, A. Cardini, A. Contu, G.M. Cossu, G.-F. Dalla Betta, A. Lai, A. Lampis, F. Mattedi, Sabina Ronchin, et al.
Within the INFN OpTiME project, we present the latest characterization results of a novel 3D silicon sensor developed as a core component of a multistage photo-detector system for fast timing with resolutions below the ps threshold. The presented device is based on FBK double-sided 3D silicon technology and is optimized for low-energy electrons and photon detection. Extensive electrical and functional tests have been performed to assess its performance, including studies of its charge collection and time response using Transient Current Technique (TCT). The results from the characterisation campaign show an intrinsic time resolution below 1 ps, displayed during TCT scan as well as the presence of a stable intrinsic charge gain without the need for a dedicated gain layer up to a factor of 10 at 200 V bias voltage, indicating the potential for radiation-tolerant silicon sensors with internal amplification. While its primary application is in fast-timing detectors, we also explore its suitability as a compact, high-resolution photosensor. Such versatility could enable its use in fields requiring precise timing, such as at pulsed fs X-ray facilities. In this work we will present the overall characterisation of the device, its performances after TCT scan and show its future applications as a fast-timing sensor.
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- 29 July 2026
- Published by Springer Nature in Journal of High Energy Physics
Machine learning techniques for jet reconstruction at LHCb and application to the search for $ H\to b\overline{b} $ and $ H\to c\overline{c} $ in $ \sqrt{s}=13 $ TeV pp collisions
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: Two machine learning techniques for jet measurements at the LHCb experiment are presented: a regression-based method for jet-energy calibration and a deep neural network algorithm for jet flavour tagging, distinguishing between b -quark, c -quark, and light parton jets. These techniques are applied to a search for inclusive $$ H\to b\overline{b} $$ $H \to b \bar{b}$ and $$ H\to c\overline{c} $$ $H \to c \bar{c}$ decays using a LHCb dataset corresponding to an integrated luminosity of 1.6 fb ^{−
1} . The observed (expected) 95% confidence level upper limits correspond to 6.6 (11.1) times the SM cross-section for the $$ H\to b\overline{b} $$ $H \to b \bar{b}$ process, and 1003 (1834) times the SM cross-section for the $$ H\to c\overline{c} $$ $H \to c \bar{c}$ process.
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- 29 July 2026
- Published by Springer Nature in Journal of High Energy Physics
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Machine learning techniques for jet reconstruction at LHCb and application to the search for $ H\to b\overline{b} $ and $ H\to c\overline{c} $ in $ \sqrt{s}=13 $ TeV pp collisions
by R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, A. A. Adefisoye, B. Adeva, M. Adinolfi, P. Adlarson, C. Agapopoulou, et al.
A bstract: Two machine learning techniques for jet measurements at the LHCb experiment are presented: a regression-based method for jet-energy calibration and a deep neural network algorithm for jet flavour tagging, distinguishing between b -quark, c -quark, and light parton jets. These techniques are applied to a search for inclusive $$ H\to b\overline{b} $$ $H \to b \bar{b}$ and $$ H\to c\overline{c} $$ $H \to c \bar{c}$ decays using a LHCb dataset corresponding to an integrated luminosity of 1.6 fb ^{−
1} . The observed (expected) 95% confidence level upper limits correspond to 6.6 (11.1) times the SM cross-section for the $$ H\to b\overline{b} $$ $H \to b \bar{b}$ process, and 1003 (1834) times the SM cross-section for the $$ H\to c\overline{c} $$ $H \to c \bar{c}$ process.

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