Studies of the resonance structure in 
                $$D^{0} \rightarrow K^\mp \pi ^\pm \pi ^\pm \pi ^\mp $$
                        D
                        0
                      →
                        K
                        ∓
                        π
                        ±
                        π
                        ±
                        π
                        ∓
               decays

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A search for CP violation in the Cabibbo-suppressed D 0 → K + K − π + π − decay mode is performed using an amplitude analysis. The measurement uses a sample of pp collisions recorded by the LHCb experiment during 2011 and 2012, corresponding to an integrated luminosity of 3.0 fb −1 . The D 0 mesons are reconstructed from semileptonic b-hadron decays into D 0 µ − X final states. The selected sample contains more than 160 000 signal decays, allowing the most precise amplitude modelling of this D 0 decay to date. The obtained amplitude model is used to perform the search for CP violation. The result is compatible with CP symmetry, with a sensitivity ranging from 1% to 15% depending on the amplitude considered. JHEP02(2019)126have peculiarities that make them particularly interesting for these studies. They have a rich resonant structure, and the variation of the strong phases over the decay phase space may provide regions with enhanced sensitivity to CP violation. This paper presents a search for CP violation in the individual amplitudes of the decay 1 D 0 → K + K − π + π − , produced in semileptonic decays of b hadrons into D 0 µ − X, where X represents any combination of undetected particles. The charge of the µ − (µ + ) lepton is used to identify D 0 (D 0 ) mesons. The D 0 µ − system is reconstructed in a sample of pp collisions collected by the LHCb experiment in 2011 and 2012 at centre-of-mass energies of 7 and 8 T eV , corresponding to integrated luminosities of 1.0 fb −1 and 2.0 fb −1 , respectively. A CP -averaged decay model is developed through a full amplitude analysis in the fivedimensional phase space of the four-body D 0 decay, where the D 0 and D 0 samples are merged. This model is then used to search for CP violation in a simultaneous fit to the distinct D 0 and D 0 samples.Such an amplitude analysis has already been performed by the CLEO experiment [7] and has been recently updated with the CLEO legacy data [8]. The analysis was based on 3000 signal decays and no CP violation was observed. This paper presents an analysis using a data sample more than 50 times larger. Searches for CP violation in this decay have also been performed by the BaBar [9], LHCb [10] and Belle [11] experiments, which are all compatible with CP symmetry.These studies use a model-independent technique to search for CP violation based on triple products [12]. Similarly the energy test [13] is used to study the D 0 → π + π − π + π − decays [14]. While these techniques are very powerful in evidencing the presence of CP violation, they do not provide any direct information on what generated the observed effect. The technique presented in this paper instead is able to associate any CP violation effect to a specific source in the resonant structure of the decay.Further motivation to study the amplitude structure of this decay mode is given by the determination of the Unitarity Triangle angle γ in B − → DK − decays, where D stands for D 0 or D 0 meson decaying to K + K − π + π − [15], for which the amplitude structure of the D 0 deca...

Section: Cp -Averaged Resultssupporting

confidence: 67%

Section: Signal Descriptionmentioning

confidence: 99%

“…The radius of the a 1 (1260) + resonance is fixed to 1.7 GeV −1 according to ref. [45] and all the other radii are fixed to 1.5 GeV −1 .…”

Section: Signal Descriptionmentioning

confidence: 99%

“…The radii of the other resonances are uniformly varied in a range of ±0.2 GeV −1 around their central values, similarly to refs. [45,48].…”

Section: Jhep02(2019)126mentioning

confidence: 99%

mentioning

confidence: 97%

See 3 more Smart Citations

Search for CP violation through an amplitude analysis of D0 → K+K−π+π− decays

Aaij

Beteta

Adeva

et al. 2019

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Measurement of CP violation in B0 → D∗±D∓ decays

Aaij¹,

Beteta²,

Ackernley³

et al. 2020

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The decay-time-dependent CP asymmetry in B 0 → D * ± D ∓ decays is measured using a data set corresponding to an integrated luminosity of 9 fb −1 recorded by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The CP parameters are measured as S D * D = −0.861 ± 0.077 (stat) ± 0.019 (syst) , ∆S D * D = 0.019 ± 0.075 (stat) ± 0.012 (syst) , C D * D = −0.059 ± 0.092 (stat) ± 0.020 (syst) , ∆C D * D = −0.031 ± 0.092 (stat) ± 0.016 (syst) , A D * D = 0.008 ± 0.014 (stat) ± 0.006 (syst). The analysis provides the most precise single measurement of CP violation in this decay channel to date. All parameters are consistent with their current world average values.

Measurement of the D → K−π+π+π− and D → K−π+π0 coherence factors and average strong-phase differences in quantum-correlated $$ D\overline{D} $$ decays

Ablikim¹,

Ачасов²,

Adlarson³

et al. 2021

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The decays D → K−π+π+π− and D → K−π+π0 are studied in a sample of quantum-correlated $$ D\overline{D} $$ D D ¯ pairs produced through the process e+e− → ψ(3770) → $$ D\overline{D} $$ D 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 D0 and a $$ {\overline{D}}^0 $$ 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 RK3π = $$ {0.52}_{-0.10}^{+0.12} $$ 0.52 − 0.10 + 0.12 and $$ {R}_{K{\pi \pi}^0} $$ R K ππ 0 = 0.78 ± 0.04, with values for the average strong-phase differences that are $$ {\delta}_D^{K3\pi }=\left({167}_{-19}^{+31}\right){}^{\circ} $$ δ D K 3 π = 167 − 19 + 31 ° and $$ {\delta}_D^{K{\pi \pi}^0}=\left({196}_{-15}^{+14}\right){}^{\circ} $$ δ D K ππ 0 = 196 − 15 + 14 ° , 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°.