Related papers: Polarization and quantum entanglement effects in $…

The semitauonic $B_c^- \to J/\psi \tau^-\bar{\nu}_\tau$ decay is optimal to scrutinize possible new physics effects in $b \to c \tau^- \bar{\nu}_\tau$ transitions as indicated by the current data on $R(D^{(*)})$ anomalies. In this work, we…

We develop an angular analysis based on the reconstruction of the helicity amplitudes from dedicated experimental data corresponding to the tripartite state composed by one qutrit and two qubits, which arises in the three-body decays of a…

In $B_c^- \to J/\psi (\to \mu^+ \mu^-)\tau^-\bar{\nu}_\tau$ decay, the three-momentum $\boldsymbol{p}_{\tau^-}$ cannot be determined accurately due to the decay products of $\tau^-$ inevitably include an undetected $\nu_{\tau}$. As a…

The proton energy spectrum and the angular distribution of the probability of the $\Lambda^+_c$ -> p + $K^-$ + $\pi^+$ decay for the polarized $\Lambda^+_c$ and the unpolarized proton are calculated in the effective quark model with chiral…

In this article, we study the three-pion $B_c$-decays $B_c^+ \to J/\psi\, \pi^+\pi^-\pi^+$, $\eta_c\, \pi^+\pi^-\pi^+ $ with dominance of the intermediate axial-vector meson $a_1(1260)$ and vector meson $\rho(770)$ in the $\pi^+\pi^-\pi^+$…

A study of the B$^+$ $\to$ J$/\psi\overline{\Lambda}$p decay using proton-proton collision data collected at $\sqrt{s} =$ 8 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 19.6 fb$^{-1}$, is presented. The…

The first observation of the $B_c^+ \to J/\psi \pi^+ \pi^0$ decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 9fb$^{-1}$, collected with the LHCb detector at…

We present a comprehensive theoretical framework for probing quantum entanglement in the decay angular distributions of a spin-$S$ particle-antiparticle pair $A\bar{A}$, where each particle decays sequentially into a two-body final state,…

Divergences that occur in density matrices of decay and scattering processes are shown to be regularized by tracing and unitarity or the optical theorem. These divergences are regularized by the lifetime of the decaying particle or the…

We present a comprehensive polarization analysis for the process $e^{+}e^{-} \rightarrow J/\psi \rightarrow$ baryon-antibaryon pairs~$B_{1}\bar{B}_{2}$. All possible helicity amplitudes for $e^{+}e^{-} \rightarrow J/\psi$ and $J/\psi…

Polarization and spin correlations in diboson systems serve as powerful tools for precision tests and searches for new physics. Recently, interpreting these observables through the lens of quantum information, for instance by examining…

The apparent thermalization of the particles produced in hadronic collisions can be obtained by quantum entanglement of the partons of the initial state once a fast hard collision is produced. The scale of the hard collision is related to…

We revisit the decay $\Lambda_b^0\to \Lambda_c^+ \ell^-\bar\nu$ ($\ell = e,\mu,\tau$) with a subsequent two-body decay $\Lambda_c^+ \to \Lambda^0 \pi^+$ in the Standard Model and in generic New Physics models. The decay's joint…

In this article, we study quantum entanglement properties of the three-body $H\to\gamma l\bar{l}$ decays (for $l=e,\mu,\tau$) within the context of the Standard Model augmented with CP-violating interactions in the lepton Yukawa sector. Our…

We calculate the invariant and helicity amplitudes for the nonleptonic decay Lambda_b -> Lambda + J/psi, psi(2S) in the covariant confined quark model. We discuss joint angular decay distributions in the cascade decay Lambda_b -> Lambda(->…

In this work, we make a systematical study on the four-body $B_{(s)} \to (\pi\pi)(\pi\pi)$ decays in the perturbative QCD approach, where the $\pi\pi$ invariant mass spectra are dominated by the vector resonance $\rho(770)$ and the scalar…

A time-integrated angular analysis of the decay $B^0_s \rightarrow J/\psi \overline{K}{}^{*}\kern-1pt(892)^{0}$, with $J/\psi \rightarrow \mu^{+} \mu^{-}$ and $\overline{K}{}^{*}\kern-1pt(892)^{0} \rightarrow K^{-} \pi^{+}$, is presented.…

The decay of a parent particle into two or more daughter particles results in an entangled quantum state as a consequence of conservation laws in the decay process. Recent experiments at Belle and BaBar take advantage of quantum…

In this paper, we study the entanglement property of a 4-particle system. In this system, two initially entangled electrons A and C are scattered by two uncorrelated positrons B and D, respectively. We calculate the entanglements among the…

We study the polarization of the J/\psi meson of the B_c -> J/\psi mu nu decay process, followed by J/\psi -> mu+ mu-, with the help of the heavy-quark spin symmetry formalism (HQSS). We adapt the ISGW wave function. Due to the clean…