Related papers: Exotic hadronic states at HERA
Models based on chiral symmetry predict pentaquarks that have relatively low masses. We briefly review both theoretical and experimental status of exotica in the light sector. Next, shall show how to extend chiral models to baryons with one…
Recent results of searches for new physics at HERA using the complete data sample corresponding to about 0.5/fb per experiment are reviewed. Searches for leptoquarks, isolated leptons (electrons, muons and taus) and a generic search for new…
The electron-proton collisions collected by the H1 and ZEUS experiments at HERA comprise a unique particle physics data set, and a comprehensive range of measurements has been performed to provide new insight into the structure of the…
Recent results on jets and the hadronic final state from the HERA collaborations H1 and ZEUS are reviewed.
Recent results on searches for new physics at Run II of the Tevatron and highlights from HERA are reported. The searches cover many different final states and a wide range of models. All analyses have at this point led to negative results,…
For many decades after the invention of the quark model in 1964 there was no evidence that hadrons are formed from anything other than the simplest pairings of quarks and antiquarks, mesons being formed of a quark-antiquark pair and baryons…
HERA is the only high energy electron-proton collider in the world today and hence has unique opportunities both to probe the structure of the proton and to search for physics beyond the Standard Model. Results are presented for…
Theoretical interpretations of the high-Q^2 events recently observed in deep-inelastic positron-proton scattering at HERA are reviewed. We discuss leptoquarks, squarks with R-parity violating couplings, and contact interactions. Bounds from…
Several experimental groups have reported evidence for baryons with flavor exotic quantum numbers that cannot be explained as $qqq$ bound states but require a minimum of five quarks -- $qqqq \bar q$. These pentaquark states include the…
We investigate the pentaquark($P$) exotic baryons as soliton-antiflavored heavy mesons bound states in the limit of infinitely heavy meson mass. Our approach respects the chiral symmetry as well as the heavy quark symmetry. The results…
We estimate the high-energy behavior of the $\Theta^+$ and $\Lambda(1520)$ production cross sections in inclusive $pp$ collisions using the $K$ exchange diagram. We show that the cross section of the $\Theta^+$-production is suppressed…
A search for events containing isolated tau leptons and large missing transverse momentum, not originating from the tau decay, has been performed with the ZEUS detector at the electron-proton collider HERA, using 130 pb^-1 of integrated…
Exotic multi-quark states are examined in the quark model and in QCD. Current status of theoretical studies of the pentaquark Theta^+ is reported. We show recent analyses of multi-quark components of baryons. A novel method to extract a…
In reference to the recently observed high Q^2, large x events in deep-inelastic positron-proton scattering at HERA, various leptoquark and supersymmetric scenarios are discussed. We study the impact of virtual leptoquark or R-parity…
The exciting discovery by LHCb of the $P_c(4312)^+$ and $P_c(4450)^+$ pentaquarks, or the suggestion of a tetraquark nature for the $Z_c(3900)$ state seen at BESIII and Belle, have triggered a lot of activity in the field of hadron physics,…
Review for exotic strange multibaryon states were obseved in the effective mass spectra of: 1)$\Lambda \pi^+$, $\Lambda \pi^-$, $\Lambda p$, $\Lambda p p$, and $\Lambda K^0_S$, $K^0_S\pi^{\pm}$ and $K^0_Sp$ subsystems.The invariant mass of…
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…
In this talk, multiquarks are studied microscopically in a standard quark model. In pure ground-state pentaquarks the short-range interaction is computed and it is shown to be repulsive, a narrow pentaquark cannot be in the groundstate. As…
The production of excited charm, D_1(2420)^0 and D_2^*(2460)^0, and charm-strange, D_{s1}(2536)^+-, mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb^-1. Masses, widths and helicity…
We review our recent findings on the structure and properties of exotic heavy hadrons, focusing on two main topics. First, we examine the role of correlations driven by the short-range Coulomb-like color interaction in hidden heavy-flavor…