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Measurement of the branching ratio of B ¯ 0 → D * + τ - ν ¯ τ relative to B ¯ 0 → D * + ℓ - ν ¯ ℓ decays with a semileptonic tagging method
Here, we report a measurement of the ratio R ( D * ) = B ( B ¯ 0 → D * + τ - ν ¯ τ ) / B ( B ¯ 0 → D * + ℓ - ν ¯ ℓ ) , where ℓ denotes an electron or a muon. The results are based on a data sample containing 772 × 1 0 6 B B ¯ pairs recorded at the Υ ( 4 S ) resonance with the Belle detector at the KEKB e + e - collider. We select a sample of B 0 B ¯ 0 pairs by reconstructing both B mesons in semileptonic decays to D * ∓ ℓ ± . We measure R ( D * ) = 0.302 ± 0.030 ( stat ) ± 0.011 ( syst ) , which is within 1.6 σ of the Standard Model theoretical expectation, where the standard deviation σ includes systematic uncertainties. We use this measurement to constrain several scenarios of new physics in a model-independent technique.
Measurement of D*±, D± and D s ± meson production cross sections in pp collisions at s = 7 TeV with the ATLAS detector
The production of D *± , D ± and D $±\atop{s}$charmed mesons has been measured with the ATLAS detector in pp collisions at √s = 7 TeV at the LHC, using data corresponding to an integrated luminosity of 280 nb -1 . The charmed mesons have been reconstructed in the range of transverse momentum 3.5 T (D)<100 GeV and pseudorapidity |η(D)|<2.1. The differential cross sections as a function of transverse momentum and pseudorapidity were measured for D *± and D ± production. The next-to-leading-order QCD predictions are consistent with the data in the visible kinematic region within the large theoretical uncertainties. Using the visible D cross sections and an extrapolation to the full kinematic phase space, the strangeness-suppression factor in charm fragmentation, the fraction of charged non-strange D mesons produced in a vector state, and the total cross section of charm production at √s = 7 TeV were derived.
Measurement of D 0 - D ¯ 0 mixing and search for indirect C P violation using D 0 → K S 0 π + π - decays
Here, we report a measurement of D 0 - D ¯ 0 mixing parameters and a search for indirect C P violation through a time-dependent amplitude analysis of D 0 → K S 0 π + π - decays. The results are based on 921 fb - 1 of data accumulated with the Belle detector at the KEKB asymmetric-energy e + e - collider. Assuming C P conservation, we measure the mixing parameters x = ( 0.56 ± 0.19 - 0.09 - 0.09 + 0.03 + 0.06 ) % and y = ( 0.30 ± 0.15 - 0.05 - 0.06 + 0.04 + 0.03 ) % , where the errors are statistical, experimental systematic, and systematic due to the amplitude model, respectively. Lastly, with C P violation allowed, the parameters | q / p | = 0.90 - 0.15 - 0.04 - 0.05 + 0.16 + 0.05 + 0.06 and arg ( q / p ) = ( - 6 ± 11 ± 3 - 4 + 3 ) ° are found to be consistent with conservation of C P symmetry in mixing and in the interference between mixing and decay, respectively.
Discovery of Function in the Enolase Superfamily: d-Mannonate and d-Gluconate Dehydratases in the d-Mannonate Dehydratase Subgroup
Abstract not provided
Measurement of prompt D 0 , D + , D *+ , and DS+$ {\mathrm{D}}_{\mathrm{S}}^{+} $ production in p–Pb collisions at sNN$ \sqrt{{\mathrm{s}}_{\mathrm{NN}}} $ = 5.02 TeV
The measurement of the production of prompt D 0 , D + , D *+, and $D_S^+$ mesons in proton–lead (p–Pb) collisions at the centre-of-mass energy per nucleon pair of \mathrm{\sqrt{s_{NN}}}$ = 5.02 TeV, with an integrated luminosity of 292 ± 11 μb -1 , are reported. Differential production cross sections are measured at mid-rapidity (-96 < y cms < 0.04) as a function of transverse momentum (p T ) in the intervals 0 < p T < 36 GeV/c for D 0 , 1 < p T < 36 GeV/c for D + and D *+ , and 2 < p T < 24 GeV/c for D + mesons. For each species, the nuclear modification factor R pPb is calculated as a function of p T using a proton-proton (pp) reference measured at the same collision energy. The results are compatible with unity in the whole p T range. The average of the non-strange D mesons R pPb is compared with theoretical model predictions that include initial-state effects and parton transport model predictions. The p T dependence of the D 0 , D + , and D *+ nuclear modification factors is also reported in the interval 1 < p T < 36 GeV/c as a function of the collision centrality, and the central-to-peripheral ratios are computed from the D-meson yields measured in different centrality classes. The results are further compared with charged-particle measurements and a similar trend is observed in all the centrality classes. The ratios of the p T -differential cross sections of D 0 , D + , D *+ , and $D_S^+$ mesons are also reported. The $D_S^+$ and D + yields are compared as a function of the charged-particle multiplicity for several p T intervals. No modification in the relative abundances of the four species is observed with respect to pp collisions within the statistical and systematic uncertainties.
Observation of an alternative χ c 0 ( 2 P ) candidate in e + e - → J / ψ D D ¯
IN this work, we perform a full amplitude analysis of the process e + e - → J / ψ D D ¯ , where D refers to either D 0 or D + . A new charmoniumlike state X * ( 3860 ) that decays to D D ¯ is determined with a significance of 6.5 σ . Its mass is ( 3862 - 32 + 26 - 13 + 40 ) MeV / c 2 , and its width is ( 201 - 67 + 154 - 82 + 88 ) MeV . The J P C = 0 + + hypothesis is favored over the 2 + + hypothesis at the level of 2.5 σ . The analysis is based on the 980 fb - 1 data sample collected by the Belle detector at the asymmetric-energy e + e - collider KEKB.
Measurement of D 0 , D + , D$^{*+}$ and D$_s^+$ production in Pb-Pb collisions at $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}=5.02$ TeV
We report measurements of the production of prompt D 0 , D + , D$^{*+}$ and D$_s^+$ mesons in Pb–Pb collisions at the centre-of-mass energy per nucleon-nucleon pair $\sqrt{s}$$_{NN}$ = 5.02 TeV, in the centrality classes 0–10%, 30–50% and 60–80%. The D-meson production yields are measured at mid-rapidity (|$y$| < 0.5) as a function of transverse momentum ($p_T$). The $p_T$ intervals covered in central collisions are: 1 < $p_T$ < 50 GeV/$c$ for D$^0$, 2 < $p_T$ < 50 GeV/$c$ for D$^+$, 3 < $p_T$ < 50 GeV/$c$ for D$^{*+}$, and 4 < $p_T$ < 16 GeV/$c$ for D$_s^+$ mesons. The nuclear modification factors ($R_{AA}$) for non-strange D mesons (D$^0$, D$^+$, D$^{*+}$) show minimum values of about 0.2 for $p_T$ = 6–10 GeV/$c$ in the most central collisions and are compatible within uncertainties with those measured at $\sqrt{{\mathrm{s}}_{\mathrm{NN}}}$ = 2.76 TeV. For D$_s^+$ mesons, the values of $R_{AA}$ are larger than those of non-strange D mesons, but compatible within uncertainties. In central collisions the average $R_{AA}$ of non-strange D mesons is compatible with that of charged particles for $p_T$ > 8 GeV/$c$, while it is larger at lower $p_T$. The nuclear modification factors for strange and non-strange D mesons are also compared to theoretical models with different implementations of in-medium energy loss.
Near-threshold states in coupled D D * − D * D * scattering from lattice QCD
The first determination of doubly charmed isospin-0 coupled-channel D D * − D * D * scattering amplitudes from lattice quantum chromodynamics (QCD) is presented. The finite-volume spectrum is computed for three lattice volumes with a light-quark mass corresponding to m π ≈ 391 MeV and is used to extract the scattering amplitudes in J P = 1 + via the Lüscher quantization condition. By analytically continuing the scattering amplitudes to complex energies, a T c c pole corresponding to a virtual bound state is found below D D * threshold. We also find a second pole, T c c ′ , corresponding to a resonance pole below the kinematically closed D * D * channel, to which it has a strong coupling. A nonzero coupling is robustly found between the S -wave D D * and D * D * channels producing a clear cusp in the D D * amplitude at the D * D * threshold energy. This suggests that the experimental T c c ′ should be observable in D D * and D * D * final states at ongoing experiments. Published by the American Physical Society 2025
Measurement of ${{\mathrm{D}}^0}$, ${{\mathrm{D}}^+}$, ${{\mathrm{D}}^{*+}}$ and ${{\mathrm{D}}^+_{\mathrm{s}}}$ production in pp collisions at ${\sqrt{{\textit{s}}}~=~5.02~{\text {TeV}}}$ with ALICE
The measurements of the production of prompt D 0 , D + , D *+ , and D$_s^+$ mesons in proton–proton (pp) collisions at $\sqrt{s}$=5.02 TeV with the ALICE detector at the Large Hadron Collider (LHC) are reported. D mesons were reconstructed at mid-rapidity (|y| < 0.5) via their hadronic decay channels D 0 → K - $π$ + , D + → K - $π$ + $π$ + , D *+ → D 0 $π$ + → K - $π$ + $π$ + , D$_s^+$ → Φ$π$ + → K + K - $π$ + , and their charge conjugates. The production cross sections were measured in the transverse momentum interval 0 < $p$T < 36 GeV/$c$ for D 0 , 1 < $p$T < 36 GeV/$c$ for D + and D *+ , and in 2 < $p$T < 24 GeV/$c$ for D$_s^+$ mesons. Thanks to the higher integrated luminosity, an analysis in finer $p$T bins with respect to the previous measurements at $\sqrt{s}$ = 7 TeV was performed, allowing for a more detailed description of the cross-section $p$T shape. The measured $p$T differential production cross sections are compared to the results at √ s = 7 TeV and to four different perturbative QCD calculations. Its rapidity dependence is also tested combining the ALICE and LHCb measurements in pp collisions at $\sqrt{s}$ = 5.02 TeV. This measurement will allow for a more accurate determination of the nuclear modification factor in p–Pb and Pb–Pb collisions performed at the same nucleon– nucleon centre-of-mass energy.
Measurement of the D → K - π + π + π- and D → K - π + π 0 coherence factors and average strong-phase differences in quantum-correlated $ D\overline{D} $ decays
The decays D → K - π + π + π - and D → K - π + π 0 are studied in a sample of quantum-correlated \( D\overline{D} \) pairs produced through the process e + e - → ψ (3770) → \( D\overline{D} \) , exploiting a data set collected by the BESIII experiment that corresponds to an integrated luminosity of 2.93 fb - 1 . Here D indicates a quantum superposition of a D 0 and a \( {\overline{D}}^0 \) meson. By reconstructing one neutral charm meson in a signal decay, and the other in the same or a different final state, observables are measured that contain information on the coherence factors and average strong-phase differences of each of the signal modes. These parameters are critical inputs in the measurement of the angle γ of the Unitarity Triangle in B - → DK - decays at the LHCb and Belle II experiments. The coherence factors are determined to be R K 3 π = \( {0.52}_{-0.10}^{+0.12} \) and \( {R}_{K{\pi \pi}^0} \) = 0 . 78 ± 0 . 04, with values for the average strong-phase differences that are \( {\delta}_D^{K3\pi }=\left({167}_{-19}^{+31}\right){}^{\circ} \) and \( {\delta}_D^{K{\pi \pi}^0}=\left({196}_{-15}^{+14}\right){}^{\circ} \) , where the uncertainties include both statistical and systematic contributions. The analysis is re-performed in four bins of the phase-space of the D → K - π + π + π - to yield results that will allow for a more sensitive measurement of γ with this mode, to which the BESIII inputs will contribute an uncertainty of around 6°.
Measurement of the τ Lepton Polarization and R ( D * ) in the Decay B ¯ → D * τ - ν ¯ τ
Here, we discuss the first measurement of the τ lepton polarization P τ ( D * ) in the decay B ¯ → D * τ - ν ¯ τ as well as a new measurement of the ratio of the branching fractions R ( D * ) = B ( B ¯ → D * τ - ν ¯ τ ) / B ( B ¯ → D * ℓ - ν ¯ ℓ ) , where ℓ - denotes an electron or a muon, and the τ is reconstructed in the modes τ - → π - ν τ and τ - → ρ - ν τ . We use the full data sample of 772 × 1 0 6 B B ¯ pairs recorded with the Belle detector at the KEKB electron-positron collider. Our findings, P τ ( D * ) = - 0.38 ± 0.51 ( stat ) - 0.16 + 0.21 ( syst ) and R ( D * ) = 0.270 ± 0.035 ( stat ) - 0.025 + 0.028 ( syst ) , are consistent with the theoretical predictions of the standard model.
Observation of D 0 - D ¯ 0 Mixing in e + e - Collisions
In this work, we observe D 0 - D ¯ 0 mixing in the decay D 0 → K + π - using a data sample of integrated luminosity 976 fb - 1 collected with the Belle detector at the KEKB e + e - asymmetric-energy collider. We measure the mixing parameters x ' 2 = ( 0.09 ± 0.22 ) × 1 0 - 3 and y ' = ( 4.6 ± 3.4 ) × 1 0 - 3 and the ratio of doubly Cabibbo-suppressed to Cabibbo-favored decay rates R D = ( 3.53 ± 0.13 ) × 1 0 - 3 , where the uncertainties are statistical and systematic combined. Our measurement excludes the no-mixing hypothesis at the 5.1 standard deviation level.
Measurement of the branching ratio of B ¯ → D ( * ) τ - ν ¯ τ relative to B ¯ → D ( * ) ℓ - ν ¯ ℓ decays with hadronic tagging at Belle
In this article we report a measurement of the branching fraction ratios R ( D ( * ) ) of B ¯ → D ( * ) τ - ν ¯ τ relative to B ¯ → D ( * ) ℓ - ν ¯ ℓ (where ℓ = e or μ ) using the full Belle data sample of 772 × 10 6 B B ¯ pairs collected at the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider. The measured values are R ( D ) = 0.375 ± 0.064 ( stat ) ± 0.026 ( syst ) and R ( D * ) = 0.293 ± 0.038 ( stat ) ± 0.015 ( syst ) . The analysis uses hadronic reconstruction of the tag-side B meson and purely leptonic τ decays. The results are consistent with earlier measurements and do not show a significant deviation from the standard model prediction.
Observation of a Resonant Structure near the D s + D s - Threshold in the B + → D s + D s - K + Decay
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 c$\overline{c}$s$\overline{s}$ 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.
Search for rare decays B + → D s ( * ) + η , D s ( * ) + K ¯ 0 , D + η , and D + K 0
We present a study of rare decay modes B + → D$^{+}_{s}$ℎ 0 , B + → D$^{*}_{s}$ + ℎ 0 , and B + → D + ℎ 0 , where ℎ 0 denotes the neutral meson η or K 0 , using a data sample of (772 ±10) ×10 6 B$\overline{B}$ events produced at the Υ(4S) resonance. The data were collected by the Belle detector operating at the asymmetric-energy KEKB collider. We find no evidence for these decays, so we set upper limits at the 90% confidence level on the branching fractions of , , and D + ℎ 0 decay modes. Along with these rare decay modes, we report improved measurements of the color-suppressed decay branching fractions $\mathscr{B}$($\overline{B}$ 0 →D 0 η) =(26.6 ±1.2 ±2.1) ×10 -5 and $\mathscr{B}$($\overline{B}$) 0 →D 0 $\overline{K}$ 0 ) =(5.6 ±0.5 ±0.2) ×10 -5 . The first and second quoted uncertainties are statistical and systematic, respectively.
Measurement of the CKM angle φ 1 in B 0 → D ¯ ( * ) 0 h 0 , D ¯ 0 → K S 0 π + π - decays with time-dependent binned Dalitz plot analysis
Here, we show a measurement of the C P -violation parameter φ 1 obtained in a time-dependent analysis of B 0 → D ¯ ( * ) 0 h 0 decays followed by D ¯ 0 → K S 0 π + π - decay. A model-independent measurement is performed using the binned Dalitz plot technique. The measured value is φ 1 = 11.7 ° ± 7.8 ° ( stat ) ± 2.1 ° ( syst ) . Treating sin 2 φ 1 and cos 2 φ 1 as independent parameters, we obtain sin 2 φ 1 = 0.43 ± 0.27 ( stat ) ± 0.08 ( syst ) and cos 2 φ 1 = 1.06 ± 0.33 ( stat ) - 0.15 + 0.21 ( syst ) . The findings are obtained with a full data sample of 772 × 1 0 6 B B ¯ pairs collected near the Υ ( 4 S ) resonance with the Belle detector at the KEKB asymmetric-energy e + e - collider.
Analysis of $D$ + → $K¯$ 0 $e$ + $ν$ $e$ and $D$ + → $π$ 0 $e$ + $ν$ $e$ semileptonic decays
Using 2.93 fb –1 of data taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we study the semileptonic decays D + → K¯ 0 e + ν e and D + → π 0 e + ν e . Here, we measure the absolute decay branching fractions B(D + → K¯ 0 e + ν e ) = (8.60 ± 0.06 ± 0.15) × 10 –2 and B(D + → π 0 e + ν e ) = (3.63 ± 0.08 ± 0.05) × 10 –3 , where the first uncertainties are statistical and the second systematic. We also measure the differential decay rates and study the form factors of these two decays. With the values of |V cs | and |V cd | from Particle Data Group fits assuming CKM unitarity, we obtain the values of the form factors at q 2 = 0, $f$ $^{K}_{+}$(0) = 0.725 ± 0.004 ± 0.012 and $f$ $^{π}_{+}$(0) = 0.622 ± 0.012 ± 0.003. Taking input from recent lattice QCD calculations of these form factors, we determine values of the CKM matrix elements |V cs | = 0.944 ± 0.005 ± 0.015 ± 0.024 and |V cd | = 0.210 ± 0.004 ± 0.001 ± 0.009, where the third uncertainties are theoretical.