Related papers: Double Polarization Observables in Pentaquark Phot…
The contributions of direct knockout processes, in addition to the diffractive production and one-pion-exchange processes associated with the phi-rho-pi and phi-gamma-pi couplings, to the polarization observables of the phi photoproduction…
Understanding the nature of the hidden charm pentaquark(like) signals in the LHCb data for $\Lambda_b^0\to J/\psi p K^-$ is a central problem of hadron spectroscopy. We propose a scenario completely different from previous ones such as…
In the hadrocharmonium picture a $\bar cc$ state and a light hadron form a bound state. The effective interaction is described in terms of the chromoelectric polarizability of the $\bar cc$ state and energy-momentum-tensor densities of the…
The LHCb collaboration have recently updated their analysis of the resonant $J/\psi\, p$ mass spectrum in the decay $\Lambda_b^0 \to J/\psi\, p\, K^-$, making use of their combined Run~1 and Run~2 data. In the updated analysis, three narrow…
In a previous work we presented a theoretical analysis of the $\Lambda_b \to J/\psi K^- p$ reaction from where a recent experiment by the LHCb collaboration at CERN claimed the existence of two hidden charm pentaquarks, $P_c(4380)^+$ and…
Prompted by several potential tetraquark states that have been reported by the LHCb, CMS and ATLAS collaborations in the di-$J/\Psi$ and $J/\Psi \Psi(2S)$ spectra, we investigate their contribution to two-photon processes. Within a…
The polarization observables in phi meson photoproduction is studied to probe the strangeness content of the nucleon. In addition to the dominant diffractive production and the one-pion-exchange process, we take into account the direct…
Recent measurements using the CLAS detector at Jefferson Lab of the reactions $\vec\gamma + p \to K^+ + \vec\Lambda$ and $\vec\gamma + p \to K^+ + \vec\Sigma^0$ have been used to extract the spin transfer coefficients $C_x$ and $C_z$ for…
I discuss few selected topics in heavy flavour photoproduction at HERA which require large integrated luminosity in order to be experimentally investigated. I present phenomenological predictions for bottom production. As a possible…
We assume that the two hidden charm pentaquark discovered at $LHCb$ are built by the three light quarks and the $c \bar{c}$ pair, both colour octets. in relative P-wave for the $\frac{5}{2}^+$ state and by the eigenvectors of the…
The LHCb experiment is designed to study the decays and properties of heavy flavoured hadrons produced in the forward region from proton-proton collisions at the CERN Large Hadron Collider. During Run 1, it has recorded the world's largest…
The production of $J/\psi$ mesons accompanied by open charm, and of pairs of open charm hadrons are observed in pp collisions at a centre-of-mass energy of 7 TeV using an integrated luminosity of $355pb^{-1}$ collected with the LHCb…
We extend our previous study of the interactions of $\bar{D}^{(*)} \Lambda_c - \bar{D}^{(*)}\Sigma_c^{(*)}$ within an analytic, unitary, coupled-channel approach by including the $J/\psi p$ channel and performing fits to the $J/\psi p$…
We report on the measurement of the $\gamma p \rightarrow J/\psi p$ cross section from $E_\gamma = 11.8$ GeV down to the threshold at $8.2$ GeV using a tagged photon beam with the GlueX experiment. We find the total cross section falls…
We use perturbative QCD, beyond the leading $\ln Q^2$ approximation, to show how measurements of diffractive $J/\psi$ production at HERA can provide a sensitive probe of the gluon density of the proton at small values of Bjorken $x$. We…
Little information is known about the polarization of gluons inside a longitudinally polarized proton. I report on the sensitivity of photoproduction experiments to it. Both jet and heavy quark production are considered.
New LHCb Collaboration results on pentaquarks with hidden charm [1] are discussed. These results fit nicely in the hadrocharmonium pentaquark scenario [2,3]. In the new data the old LHCb pentaquark $P_c(4450)$ splits into two states…
The rare three body decay of a Higgs boson to a lepton-anti lepton pair and a photon has begun to attract attention, after the first evidence for the $H\to Z\gamma$ at CMS and ATLAS, which is a sub process of $H \to \ell^+ \ell^- \gamma$ .…
The hidden charm pentaquark state $P_c(4450)$ observed recently by the LHCb collaboration may be of molecular nature, as advocated by some unitary approaches that also predict pentaquark partners in the strangeness $S=-1$ sector. In this…
We study the possibility that four $\Xi$ resonances $(\Xi(1620)$, $\Xi(1690)$, $\Xi(1820)$, $\Xi(1950))$ could correspond to pentaquark states, in the form of meson-baryon bound systems. We also explore the possible existence of doubly…