The inclusive charged hadron momentum spectra from the $ and $' decays produced in e+ecoilisions at SPEAR are presented, The data were obtained with a small solid-angle, single-arm magnetic spectrometer with good particle identification abilities centered at 90 degrees with respect to the beams. The particle-separated invariant cross sections are compared with data from e+ecollisions at 6 = 4.8...

By assuming that there is no significant intrinsic polarization of the gluon, we have computed the polarized quark contributions to the proton’s spin under SU(3) flavor symmetry breaking for the polarized sea and have performed a global leading-order QCD fit to obtain the spin-dependent quark distributions, which could be used as input for analyzing lepton-hadron and hadron-hadron collisions.

Hadron physics is that part of QCD dealing with hadron structure and vacuum structure, almost all of which is nonperturbative in nature. Some of the open problems in this field are outlined. We argue that hadron physics is a distinct subfield, no longer within particle physics, and not at all the same as classical nuclear physics. We believe that it needs to be better organized, and that a firs...

In this work the $k_{\perp}$-factorization formalism is applied to compute exclusive $Z^0$ boson photoproduction in $ep$ and $eA$ collisions. The study also extended $pp$ $AA$ processes. nuclear effects are investigated considering heavy light ions. Analytical models for unintegrated gluon distribution taken into account corresponding theoretical uncertainty quantified. analysis done electron-i...

The $X(3872)$, whose mass coincides with the $D^0\bar D^{*0}$ threshold, is most extended hadron object. Since its discovery in 2003, debates have never stopped regarding internal structure. We propose a new object, $X$ atom, which $D^\pm D^{*\mp}$ composite system positive charge parity and of $(3879.89\pm0.07)$ MeV, formed mainly due to Coulomb force. show that null signal atom can be used pu...

The $X(3872)$, whose mass coincides with the $D^0\bar D^{*0}$ threshold, is most extended hadron object. Since its discovery in 2003, debates have never stopped regarding internal structure. We propose a new object, $X$ atom, which $D^\pm D^{*\mp}$ composite system positive charge parity and of $(3879.89\pm0.07)$ MeV, formed mainly due to Coulomb force. show that null signal atom can be used pu...

Calculation of the hadron spectrum has been a central goal of Lattice QCD for 20 years. A precision calculation of the hadron spectrum would be a validation of QCD, and a validation of Lattice QCD as a calculational technique. It would give us con dence when we apply lattice QCD to calculating other quantities. In addition we would be able to clarify the nature of observed hadrons and predict w...

Hadron production in single and central diffraction dissociation is studied in a model which includes soft hadron interaction as controlled by a supercritical pomeron parametrization and hard diffraction. Hard diffraction is described using leading-order QCD matrix elements together with the parton distributions for the proton, the less well known photon parton densities and a conjectured parto...

The hadron production in ee collisions is studied assuming that particles originate in a hadron gas at thermal and chemical equilibrium. The parameters of the hadron gas are determined with a fit to the average multiplicities of various hadron species measured at LEP and PEP-PETRA colliders. An impressive agreement is found between the predictions of this model and data for almost all particles...