Search results for "baryon"
showing 10 items of 759 documents
Studies of Λcproduction in pp and p-Pb collisions 1 with ALICE at 2 the LHC
2017
A Large Ion Collider Experiment (ALICE) was designed to study the strongly interacting medium created in heavy-ion collisions at LHC energies, the Quark Gluon Plasma (QGP). Heavy quarks (charm and beauty), produced in the early stages of the collisions, are among the most powerful probes to study this state of matter. To study the QGP effects, it is important to establish reference data, which is done by analysing results from pp and p-Pb collisions.We report on the charmed baryon Λc measurement in pp collisions at √s = 7 TeV and in p-Pb collisions at √sNN = 5.02 TeV with the ALICE experiment, through the reconstruction of the decay channels Λc + → p K S 0 and Λc + → pK − π + .
Doubly charmed Ξcc molecular states from meson-baryon interaction
2018
Stimulated by the new experimental LHCb findings associated with the ${\mathrm{\ensuremath{\Omega}}}_{c}$ states, some of which we have described in a previous work as being dynamically generated through meson-baryon interaction, we have extended this approach to make predictions for new ${\mathrm{\ensuremath{\Xi}}}_{cc}$ molecular states in the $C=2$, $S=0$, and $I=1/2$ sector. These states manifest themselves as poles in the solution of the Bethe-Salpeter equation in coupled channels. The kernels of this equation were obtained using general Lagrangians coming from the hidden local gauge symmetry or massive Yang-Mills theory, and the interactions are dominated by the exchange of light vect…
Prediction of NarrowN*andΛ*Resonances with Hidden Charm above 4 GeV
2010
Up to now, all established baryons can be ascribed into 3-quark (qqq) configurations [1], although some of them were suggested to be meson-baryon dynamically generated states [2–8] or states with large (qqqq¯ q) components [9–11]. A difficulty to pin down the nature of these baryon resonances is that the predicted states from various models are around the same energy region and there are always some adjustable ingredients in each model to fit the experimental data. In this letter, we report a study of the interactions between various charmed mesons and charmed baryons within the framework of the coupled channel unitary approach with the local hidden gauge formalism. Several meson-baryon dyn…
Quark-model study of few-baryon systems
2005
We review the application of non-relativistic constituent quark models to study one, two and three non-strange baryon systems. We present results for the baryon spectra, potentials and observables of the NN, N$\Delta$, $\Delta\Delta$ and NN$^*(1440)$ systems, and also for the binding energies of three non-strange baryon systems. We make emphasis on observable effects related to quark antisymmetry and its interplay with quark dynamics.
Spin, helicity and flavour patterns in exclusive decays of bottom mesons into baryon-antibaryon pairs
1989
I use the constituent quark model to calculate the exclusive decays of bottom mesons into ground state baryon-antibaryon pairs mediated by the weakb→c and b→u transitions. TheW-exchange contributions to these decays are found to be negligible. For theW-decay contributions I find that the simple colour-flavour structure of the 1/2+ and 3/2+ ground state baryons together with the current-current nonleptonic Hamiltonian leads to many simple and testable predictions. Notable among these is the predicted vanishing of decays involving 3/2+ baryons as in\(\overline {B^0 } (B^ - ) \to 3/2^ + \overline {1/2^ + } \) and\(\overline {B^0 } (B^ - ) \to 3/2^ + \overline {3/2^ + } \). An experimental veri…
The baryonic spectrum of QCD 2 in the chiral limit
1991
Abstract A description of the baryonic spectrum of quantum chromodynamics in one-space-one-time dimensions for massless quarks is presented. The theory has been studied in the equivalent non-abelian bosonic representation, and four-point functions of the colored meson fields under the simplifying assumption of two colors have been calculated. The crucial role of the chiral sector in providing baryon number has been unveiled. Excited baryon states appear as pseudomesonic excitations on top of the massless baryons associated with the chiral fields.
Resonances in QCD
2015
We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015. A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions: What is needed to understand the physics of resonances in QCD? Where does QCD lead us to expect resonances with exotic quantum numbers? What experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with ${\it up}$, ${\it down}$ and ${\it strange}$ quark content were considered. For heavy-light and heavy-heavy meson systems, those with ${\it charm}$ quarks were the focus. This docum…
QCD Confinement and the Meson Spectrum
2003
From QCD and lattice calculations two specific forms of quark confining potential, a strict linear and a screened linear confinement, come out. Both forms of the potential, implemented by the one gluon exchange interaction, are applied to the description of heavy quarkonia: cc and bb. Applications to light hadrons, mesons and baryons, are also commented.
About the realization of chiral symmetry in QCD2
1992
Two dimensional massless Quantum Chromodynamics presents many features which resemble those of the true theory. In particular the spectrum consists of mesons and baryons arranged in flavor multiplets without parity doubling. We analyze the implications of chiral symmetry, which is not spontaneously broken in two dimensions, in the spectrum and in the quark condensate. We study how parity doubling, an awaited consequence of Coleman's theorem, is avoided due to the dimensionality of space-time and confinement. We prove that a chiral phase transition is not possible in the theory.
Semileptonic decays of the lightJP=1/2+ground state baryon octet
2008
We calculate the semileptonic baryon octet-octet transition form factors using a manifestly Lorentz covariant quark model approach based on the factorization of the contribution of valence quarks and chiral effects. We perform a detailed analysis of SU(3)-breaking corrections to the hyperon semileptonic decay form factors. We present complete results on decay rates and asymmetry parameters including lepton mass effects for the rates.