Related papers: A Discussion on Triangle Singularities in the $\La…

The singularity of specific heat ($C_p$) and related properties (viz. thermal expansion coefficient, compressibility and pressure coefficient) of liquid $^4He$ at $\lambda-$point is studied and the accuracy of its logarithmic nature as…

We find that several thresholds can contribute to the enhancements of the newly observed heavy pentaquark candidates $P_c^+(4380)$ and $P_c^+(4450)$ via the anomalous triangle singularity (ATS) transitions in the specific kinematics of…

The role of triangle mechanism in the decay process $J/\psi \to K^- K^+ a_1(1260)$ is probed. In this mechanism, a close-up resonance with mass $1823$ MeV and width $122$ MeV decays into $K^* \phi, K^* \to K \pi$ and then $K^* \bar{K}$…

We study the near-threshold $J/\psi$ meson production on protons and nuclei by considering incoherent direct non-resonant $K^-p \to {J/\psi}\Lambda$ and two-step resonant ${K^-}p \to P_{cs}(4459)^0 \to {J/\psi}\Lambda$ charmonium production…

We calculate the leading contribution to the weak $\Lambda \Lambda K$ coupling in heavy baryon chiral perturbation theory, including the SU(3) breaking terms arising at one-loop. This coupling gives the leading one-boson exchange amplitude…

We study the appearance of structures in the decay of the $B^-$ into $K^- \pi^- D_{s0}^+(2317)$ and $K^- \pi^- D_{s1}^+(2460)$ final states by forming invariant mass distributions of $\pi^- D_{s0}^+$ and $\pi^- D_{s1}^+$ pairs,…

The rates of the $X(3872)\to\pi^0\pi^0\chi_{c1}$ and $X(3872)\to \pi^+\pi^-\chi_{c1}$ decays are estimated in the model of the triangle loop diagrams with charmed $D^*\bar DD$ and $\bar D^*D\bar D$ mesons in the loops. There are the…

Triangle and other kinematic singularities are very sensitive to the precise masses and widths of the intervening particles. Therefore, the effect that the heavy-ion collision medium can have on those masses and widths, as captured by…

The spectrum of charmonium resonances contains a number of unanticipated states along with several conventional quark-model excitations. The hadrons of different quantum numbers $J^P$ appear in a fairly narrow energy band, where $J^P$…

We study the elliptic and triangular flow of charmonium states, or $J/\psi$, $\psi(2S)$, and $\chi_c(1P)$ mesons in heavy ion collisions. Starting from the evaluation of charmonia transverse momentum distributions and yields, we calculate…

We demonstrate that triangle singularity (TS) and box singularity (BS) mechanisms can produce unique narrow enhancements at the $\Lambda_c\bar{D}$ and $\Lambda_c\bar{D}^*$ thresholds in the invariant mass spectra of $J/\psi p$ and $J/\psi…

We perform a theoretical analysis of the $\Lambda_b \to J/\psi K^- p$ reaction from where a recent LHCb experiment extracts a $\Lambda(1405)$ contribution in the $K^- p$ spectrum close to threshold and two baryon states of hidden charm in…

The cross sections for the reactions pp -> p Lambda^0K^+ and pn -> n Lambda^0K^+ are calculated near threshold of the final states. The theoretical ratio of the cross sections R = sigma(pn -> n Lambda^0K^+)/ sigma(pp ->p\Lambda^0K^+) = 3…

The LHCb data on $B^+\to J/\psi\phi K^+$ show four peaks and three dips in the $J/\psi\phi$ invariant mass distribution, and the peaks are interpreted as $X(4140)$, $X(4274)$, $X(4500)$ and $X(4685)/X(4700)$ resonance contributions.…

An amplitude analysis of the decay $\Lambda_b^0\to D^0 p \pi^-$ is performed in the part of the phase space containing resonances in the $D^0 p$ channel. The study is based on a data sample corresponding to an integrated luminosity of 3.0…

Two Body Dirac Equations (TBDE) of Dirac's relativistic constraint dynamics have been successfully applied to obtain a covariant nonperturbative description of QED and QCD bound states. Coulomb-type potentials in these applications lead…

We compare contributions from the triangle diagram and the $D\bar D^*$ bubble chain to the processes of $e^{+}e^{-}\rightarrow J/\psi\pi^{+}\pi^{-}$ and $e^{+}e^{-}\rightarrow (D\bar D^*)^\mp\pi^{\pm}$. By fitting the $J/\psi\pi$ maximum…

A full amplitude analysis of $\Lambda_b^0 \to J/\psi p \pi^-$ decays is performed with a data sample acquired with the LHCb detector from 7 and 8 TeV $pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$. A significantly…

The LHCb Collaboration announcement regarding the observation of the $P_{\Psi s}^{\Lambda} (4459)$ stated that it might consist of two resonances rather than a single one. Naturally, the structure and composition of $P_{\Psi…

Observations of exotic structures in the $J/\psi p$ channel, that we refer to as pentaquark-charmonium states, in $\Lambda_b^0\to J/\psi K^- p$ decays are presented. The data sample corresponds to an integrated luminosity of 3/fb acquired…