Measurements of the absolute branching fractions of the doubly Cabibbo-suppressed decays $D^+\to K^+π^0$, $D^+\to K^+η$ and $D^+\to K^+η^{\prime}$
(2025)
Measurement of branching fractions and CP asymmetries in Λ b 0 Ξ b 0 → p K S 0 h − decays
Journal of High Energy Physics Springer 2025:10 (2025) 169
Abstract:
A study of Λb0 and Ξb0 baryon decays to the final states pKS0π− and pKS0K− is performed using pp collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. The decays Λb0→pKS0K− and Ξb0→pKS0K− are observed for the first time, with significances reaching eight standard deviations. The branching fractions and integrated CP asymmetries are measured for the Λb0→pKS0π−, Λb0→pKS0K−, and Ξb0→pKS0K− decays. For the decay Λb0→pKS0π−, the CP asymmetries are measured in different regions of the Dalitz plot. No evidence of CP violation is observed.Updated measurement of CP violation and polarisation in B s 0 → J / ψ K ¯ ∗ 892 0 decays
Journal of High Energy Physics Springer 2025:10 (2025) 173
Abstract:
A time-integrated angular analysis of the decay Bs0→J/ψK¯∗8920, with J/ψ → μ+μ− and K¯∗8920→K−π+, is presented. The analysis employs a sample of proton-proton collision data collected by the LHCb experiment during 2015–2018 at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb−1. A simultaneous maximum-likelihood fit is performed to the angular distributions in bins of the K−π+ mass. This fit yields measurements of the CP-averaged polarisation fractions and CP asymmetries for the P-wave component of the K−π+ system. The longitudinal and parallel polarisation fractions are determined to be f0 = 0.534 ± 0.012 ± 0.009 and f|| = 0.211 ± 0.014 ± 0.005, respectively, where the first uncertainty is statistical and the second is systematic. The CP asymmetries are measured with 3–7% precision and are found to be consistent with zero. These measurements, along with an updated determination of the branching fraction relative to the B0 → J/ψK*0 decay, are combined with previous LHCb results, providing the most precise values for these observables to date.First Observation of Quantum Correlations in e+e−→XDD¯ and C -Even Constrained DD¯ Pairs
Physical Review Letters American Physical Society (APS) 135:17 (2025) 171901
Abstract:
<jats:p>The study of meson pairs produced with quantum correlations gives direct access to parameters that are challenging to measure in other systems. In this Letter, the existence of quantum correlations due to charge-conjugation symmetry <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>C</a:mi></a:math> are demonstrated in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>D</c:mi><c:mover accent="true"><c:mi>D</c:mi><c:mo stretchy="true">¯</c:mo></c:mover></c:math> pairs produced through the processes <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:msup><g:mi>e</g:mi><g:mo>+</g:mo></g:msup><g:msup><g:mi>e</g:mi><g:mo>−</g:mo></g:msup><g:mo stretchy="false">→</g:mo><g:mrow><g:mi>D</g:mi><g:mover accent="true"><g:mi>D</g:mi><g:mo stretchy="true">¯</g:mo></g:mover></g:mrow></g:math>, <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline"><l:msup><l:mi>e</l:mi><l:mo>+</l:mo></l:msup><l:msup><l:mi>e</l:mi><l:mo>−</l:mo></l:msup><l:mo stretchy="false">→</l:mo><l:mrow><l:msup><l:mi>D</l:mi><l:mo>*</l:mo></l:msup><l:mover accent="true"><l:mi>D</l:mi><l:mo stretchy="true">¯</l:mo></l:mover></l:mrow></l:math>, and <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"><q:msup><q:mi>e</q:mi><q:mo>+</q:mo></q:msup><q:msup><q:mi>e</q:mi><q:mo>−</q:mo></q:msup><q:mo stretchy="false">→</q:mo><q:mrow><q:msup><q:mi>D</q:mi><q:mo>*</q:mo></q:msup><q:mrow><q:msup><q:mover accent="true"><q:mi>D</q:mi><q:mo stretchy="true">¯</q:mo></q:mover><q:mo>*</q:mo></q:msup></q:mrow></q:mrow></q:math>, where the lack of charge superscripts refers to an admixture of neutral-charm-meson particle and antiparticle states, using <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline"><v:mn>7.13</v:mn><v:mtext> </v:mtext><v:mtext> </v:mtext><v:msup><v:mi>fb</v:mi><v:mrow><v:mo>−</v:mo><v:mn>1</v:mn></v:mrow></v:msup></v:math> of <x:math xmlns:x="http://www.w3.org/1998/Math/MathML" display="inline"><x:msup><x:mi>e</x:mi><x:mo>+</x:mo></x:msup><x:msup><x:mi>e</x:mi><x:mo>−</x:mo></x:msup></x:math> collision data collected by the BESIII experiment between center-of-mass energies of 4.13–4.23 GeV. Processes with either <z:math xmlns:z="http://www.w3.org/1998/Math/MathML" display="inline"><z:mi>C</z:mi></z:math>-even or <bb:math xmlns:bb="http://www.w3.org/1998/Math/MathML" display="inline"><bb:mi>C</bb:mi></bb:math>-odd constraints are identified and separated. A procedure is presented that harnesses the entangled production process to enable measurements of <db:math xmlns:db="http://www.w3.org/1998/Math/MathML" display="inline"><db:msup><db:mi>D</db:mi><db:mn>0</db:mn></db:msup></db:math>-meson hadronic parameters. This Letter provides the first confirmation of quantum correlations in <fb:math xmlns:fb="http://www.w3.org/1998/Math/MathML" display="inline"><fb:msup><fb:mi>e</fb:mi><fb:mo>+</fb:mo></fb:msup><fb:msup><fb:mi>e</fb:mi><fb:mo>−</fb:mo></fb:msup><fb:mo stretchy="false">→</fb:mo><fb:mi>X</fb:mi><fb:mrow><fb:mi>D</fb:mi><fb:mover accent="true"><fb:mi>D</fb:mi><fb:mo stretchy="true">¯</fb:mo></fb:mover></fb:mrow></fb:math> processes and the first observation of a <kb:math xmlns:kb="http://www.w3.org/1998/Math/MathML" display="inline"><kb:mi>C</kb:mi></kb:math>-even constrained <mb:math xmlns:mb="http://www.w3.org/1998/Math/MathML" display="inline"><mb:mi>D</mb:mi><mb:mover accent="true"><mb:mi>D</mb:mi><mb:mo stretchy="true">¯</mb:mo></mb:mover></mb:math> system. The procedure is applied to measure <qb:math xmlns:qb="http://www.w3.org/1998/Math/MathML" display="inline"><qb:msubsup><qb:mi>δ</qb:mi><qb:mrow><qb:mi>K</qb:mi><qb:mi>π</qb:mi></qb:mrow><qb:mi>D</qb:mi></qb:msubsup></qb:math>, the strong phase between the <sb:math xmlns:sb="http://www.w3.org/1998/Math/MathML" display="inline"><sb:mrow><sb:msup><sb:mrow><sb:mi>D</sb:mi></sb:mrow><sb:mrow><sb:mn>0</sb:mn></sb:mrow></sb:msup><sb:mo stretchy="false">→</sb:mo><sb:msup><sb:mrow><sb:mi>K</sb:mi></sb:mrow><sb:mrow><sb:mo>−</sb:mo></sb:mrow></sb:msup><sb:msup><sb:mrow><sb:mi>π</sb:mi></sb:mrow><sb:mrow><sb:mo>+</sb:mo></sb:mrow></sb:msup></sb:mrow></sb:math> and <vb:math xmlns:vb="http://www.w3.org/1998/Math/MathML" display="inline"><vb:mrow><vb:mrow><vb:msup><vb:mrow><vb:mover accent="true"><vb:mrow><vb:mi>D</vb:mi></vb:mrow><vb:mrow><vb:mo stretchy="true">¯</vb:mo></vb:mrow></vb:mover></vb:mrow><vb:mrow><vb:mn>0</vb:mn></vb:mrow></vb:msup></vb:mrow><vb:mo stretchy="false">→</vb:mo><vb:msup><vb:mrow><vb:mi>K</vb:mi></vb:mrow><vb:mrow><vb:mo>−</vb:mo></vb:mrow></vb:msup><vb:msup><vb:mrow><vb:mi>π</vb:mi></vb:mrow><vb:mrow><vb:mo>+</vb:mo></vb:mrow></vb:msup></vb:mrow></vb:math> decay amplitudes, which results in the determination of <ac:math xmlns:ac="http://www.w3.org/1998/Math/MathML" display="inline"><ac:mrow><ac:msubsup><ac:mrow><ac:mi>δ</ac:mi></ac:mrow><ac:mrow><ac:mi>K</ac:mi><ac:mi>π</ac:mi></ac:mrow><ac:mrow><ac:mi>D</ac:mi></ac:mrow></ac:msubsup><ac:mo>=</ac:mo><ac:mo stretchy="false">(</ac:mo><ac:msubsup><ac:mrow><ac:mn>192.8</ac:mn></ac:mrow><ac:mrow><ac:mo>−</ac:mo><ac:mn>12.4</ac:mn><ac:mo>−</ac:mo><ac:mn>2.4</ac:mn></ac:mrow><ac:mrow><ac:mo>+</ac:mo><ac:mn>11.0</ac:mn><ac:mo>+</ac:mo><ac:mn>1.9</ac:mn></ac:mrow></ac:msubsup><ac:mo stretchy="false">)</ac:mo><ac:mo>°</ac:mo></ac:mrow></ac:math>. The potential for measurements of other hadronic decay parameters and charm mixing with these and future datasets is also discussed.</jats:p>Novel measurement of the strong-phase difference between D0→K−π+ and D¯0→K−π+ decays using C -even and C -odd quantum-correlated DD¯ pairs
Physical Review D American Physical Society (APS) 112:7 (2025) 72006