相关论文: An explanation why the Theta+ is seen in some expe…
To understand the whole set of positive and null data on the Theta+(1530)-production, we suggest the hypothesis that multiquark hadrons are mainly generated from many-quark states, which emerge either as short-term hadron fluctuations, or…
On the basis of existing data, we suggest such a mechanism of production for exotic hadrons that can explain, at least qualitatively, why the Theta+-baryon is seen in some experiments and not in others. With our hypothesis, production of…
The contradiction between evidence for and against the existence of the Theta+ pentaquark might be resolved if it only appears as a result of a particular production mechanism which is present in some experiments and absent in others. We…
Additional broader I=0 states in the KN channel near $\Theta^+$(1540) are expected in many models, making the absence of any signature in the K$^+$-deuteron scattering data even more puzzling. In an ideal "three-body" picture the $\Theta$…
Evidence for the $\Theta^+$ pentaquark is still sketchy at the present time. This state, if it exists, has a small width and consequently a small production cross section. No single experiment has overwhelming evidence for the $\Theta^+$…
I review some selected aspects of the phenomenology of multiquark states discovered in high energy experiments. They have four valence quarks (called tetraquarks) and two of them are found to have five valence quarks (called pentaquarks),…
A new mechanism of the production of hypothetical $\Theta(ud\bar{s}ud)^+$ pentaquark state is suggested. The considered mechanism is based on the exchange by exotic Regge trajectories in the $t$ channel. It is shown that the momentum…
The hadron production in relativistic heavy ion collisions is well described by the quark combination model. The mixed ratios for various hadrons and the transverse momentum spectra for long-life hadrons are predicted and agree with recent…
In this paper we explain and discuss some fundamental features of various models which are QCD-based and proposed to explain the hadron spectrum.
After explaining necessity of exotic hadrons, we discuss mechanisms which could determine production of the exotic Theta-baryon. A possible important role of resonances (producing the Theta in real or virtual decays) is emphasized for…
We review the experimental evidence on firstly, strangeness production as a signature for the QCD phase transition and secondly, pentaquarks, the latest and most exotic manifestations of strangeness in hadrons.
Production of pentaquark $\Theta^+$ baryons in central relativistic heavy ion collisions is studied in a kinetic model. Assuming that a quark-gluon plasma is produced in the collisions, we first determine the number of $\Theta^+$ produced…
The possibility of the existence of multiquark hadrons made of 4-quark for mesons and 5-quark for baryons was predicted by Gell-Mann in Ref. [1]. The renewed interest for the search of exotic pentaquark states was initiated by the paper by…
We study properties of the pentaquark particle Theta+ with emphasis on the role of chiral symmetry. It is shown that when chiral force is sufficiently strong, the positive parity Theta+ may be realized with a lower mass relative to the…
Heavy quarks provide a new dimension to QCD, allowing tests of fundamental theory, the nature of color confinement, and the production of new exotic multiquark states. I also discuss novel explanations for several apparently anomalous…
Experimental evidence for and against the existence of pentaquarks has accumulated rapidly in the last three years. If they exist, they would be dramatic examples of hadronic states beyond our well-tested and successful particle models. The…
A critical look is taken at both positive and null evidence for the $\Theta^+$ pentaquark. Potential problems with experiments will be discussed and the question of what conclusion can be drawn from both the positive and the null results is…
The high prompt production cross section of X(3872) at hadron colliders has shown to be very informative about the quark nature of the X, Y, Z states. We present here a number of results on X production in pp(pbar) collisions obtained with…
The production of strange pentaquark states (e.g. Theta baryons and Xi^-- states) in hadronic interactions within a Gribov-Regge approach is explored. In this approach the Theta^+(1540) and the Xi Pentaquark are produced by disintegration…
Instrumenting the LHC to measure the outgoing protons in the process pp -> p+X+p opens up new possibilities for physics studies in the Standard Model and beyond. In this talk I first present an overview of the underlying QCD calculation and…