Related papers: The X(3872) as a mass distribution
The quantum numbers J^PC = 1++ of the X(3872) and the proximity of its mass to the D*0 anti-D0 threshold imply that it is either a loosely-bound hadronic molecule whose constituents are a superposition of D*0 anti-D0 and D0 anti-D*0 or it…
If the $X(3872)$ is a weakly bound charm-meson molecule, it can be produced by the creation of $D^{*0} \bar{D}^0$ or $D^{0} \bar{D}^{*0}$ at short distances followed by the formation of the bound state from the charm-meson pair. The $X$ can…
We report on the search for a charged partner of the X(3872) in the decay $B \to X^\pm K$, $X^\pm \to J/\psi \pi^\pm \pi^0$, using 213 million $B\bar B$ events collected at the $\Upsilon(4S)$ resonance with the BaBar detector at the PEP-II…
The isospin-breaking decay $X(3872)\to(D^*\bar D+ \bar D^*D) \to\pi^0D\bar D\to\pi^0\pi^+\pi^-$ is discussed. In its amplitude there is a triangle logarithmic singularity, due to which the dominant contribution to…
Radiative decays of $X(3872)$ are studied in single-channel approximation (SCA) and in the coupled-channel (CC) approach, where the decay channels $D\bar D^*$ are described with the string breaking mechanism. In SCA the transition rate…
Exotic charmonium-like states have been observed by various experiments over the last 15 years, but their nature is still under discussion. Photo-(muo)production is a new promising instrument to study them. COMPASS, a fixed target…
We discuss how the latest data on X(3872) in B and B_s decays speak about its tetraquark nature. The established decay pattern, including the up to date observations by CMS, are explained by the mixing of two quasi-degenerate, unresolvable,…
The decays of the X(3872) to P-wave quarkonia are calculated under the assumption that it is a shallow bound state of neutral charmed mesons. The X(3872) is described using an effective theory of nonrelativistic D mesons and pions (X-EFT).…
We present recent studies of charmonium multiquark states. We use different interacting models and numerical methods to study deeply bound four-quark states and meson-meson molecules. No deeply bound four-quark states are found in our…
We perform a study of the $X(3872)$ lineshape using the data samples of $e^+e^-\to\gamma X(3872)$, $X(3872)\to D^0\bar{D}^0 \pi^0$ and $\pi^+\pi^- J/\psi$ collected with the BESIII detector. The effects of the coupled-channels and the…
We present a study of the decays B^{0,+} --> J/psi pi^+ pi^- pi^0 K^{0,+}, using 467 10^6 BBbar pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872) --> J/psi omega, with product branching fractions B(B^+…
Two decades after its unexpected discovery, the properties of the $X(3872)$ exotic resonance are still under intense scrutiny. In particular, there are doubts about its nature as an ensemble of mesons or having any other internal structure.…
We have studied isospin breaking effects in the X(3872) resonance and found a natural explanation for the branching fraction of the X decaying to $J/\psi$ with two and three pions being close to unit. Within our framework the X(3872) is a…
The X(3872) radiative decay is discussed by employing a two-meson multichannel model with the charmonium components, which explains many of the other observed features of X(3872). We have found that the ratio of the branching fractions of…
We discuss the nature of the $\chi_b(3P)$ and $X(3872)$ mesons: Are the $\chi_b(3P)$'s standard $b \bar b$ mesons or $b \bar b$ states with a significative continuum component? Is the $X(3872)$ a $c \bar c$ state with continuum coupling…
We determine the contribution of long-range pion interactions to the $X(3872)$ dynamics, assuming it is a loosely bound $D^0 \bar{D}^{*0}$ molecule. Our result is based on the distorted wave Born approximation in non-relativistic quantum…
We study the potential of $X(3872)$ at finite temperature in the Born-Oppenheimer approximation under the assumption that it is a tetraquark. We argue that, at large number of colors, it is a good approximation to assume that the potential…
Assuming that $X(3872)$ is a mixture between $2P$ charmonium and $\bar{D}D^{*}$ molecular states with $J^{PC}=1^{++}$, an analysis of $X(3872)$ radiative decays into $J/\psi \gamma$ and $\psi(2S)\gamma$ is presented. The modification of the…
The BaBar analysis which favours $2^{-+}$ quantum numbers for the X(3872) implies that it may be none other than the 1D2 charmonia state. In that case the isospin breaking in closed flavour modes may be the result of re-scattering from open…
In a recent paper Phys.Rev.Lett. 111, 042002 (2013) (arXiv:1304.0846), the charmonium state X(3872) is studied in the framework of an effective field theory. In that work it is claimed that (i) the one-pion exchange (OPE) alone provides…