The 2009 Europhysics Conference on High Energy Physics

Inclusive non-diffractive photoproduction of rho(770)^0, K^*(892)^0 and phi(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average \gamma p centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5<p_T<7 GeV and the rapidity range |y_{lab}|<1. Differential cross sections are presented as a function of...

A first measurement of the charge asymmetry in the scattered hadronic final state in high Q^2 deep-inelastic ep neutral current scattering at HERA has been made. The difference between the normalised distribution of the scaled momentum, xp, for positive and negative particles, measured in the current region of the Breit frame, has been studied together with its evolution as a function of Q^2....

The charged multiplicity distributions and the mean charged multiplicity have been investigated in inclusive neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb-1. The measurements were performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic centre-of-mass frame....

Inclusive K0sK0s production in ep collisions at HERA was studied with the ZEUS detector using an integrated luminosity of 0.5 fb-1. Enhancements in the mass spectrum were observed and are attributed to the production of f2(1270)/a20(1320), f2'(1525) and f0(1710). Masses and widths were obtained using a fit which takes into account theoretical predictions based on SU(3) symmetry arguments,...

One of the primary goals of the high-energy spin physics program at RHIC is to determine the polarized gluon contribution, $\Delta G$, to proton spin. The most recent STAR measurements of the longitudinal double-spin asymmetries, $A_{LL}$, for the inclusive production of jets, neutral and charged pions at mid-rapidity from collisions at a center of mass energy of $\sqrt{s} = 200\,$ GeV...

The HERMES experiment at HERA has performed a new determination of the strange quark distribution s(x) from multiplicities of charged kaons in semi-inclusive deep-inelastic scattering (SIDIS) of 27.6 GeV electrons/positrons from deuterium. The extracted distribution function (DF) is much softer than that previously derived from dimuon events in neutrino/antineutrino scattering and those...

The new results on quark helicity distributions and on gluon polarization Delta_G/G from the COMPASS experiment will be presented. COMPASS is polarized DIS experiment using polarized muons with an energy of 160 GeV scattered off a polarised deuteron and proton targets. Quark helicity distributions are obtained from inclusive and semi-inclusive reactions from 2002-2004 and 2006...

Exclusive processes in hard electroproduction with asymptotic gamma* p center of mass energy is one of the best place for understanding QCD in the perturbative Regge limit. The HERA experiment recently provided precise data for rho electroproduction, including all spin density matrix elements. From QCD, it is expected that such a process should factorize between a hard (calculable)...

Spin Density Matrix Elements (SDMEs) describing the angular distribution of exclusive rho^0 electroproduction and decay are determined in the HERMES experiment with 27.6 GeV beam energy on unpolarized hydrogen and deuterium targets, and on transversely polarized hydrogen target. Those are extracted in the kinematic region 1 < Q^2 < 7 GeV^2, 3 < W < 6.3 GeV, and -t < 0.4 GeV^2. Within the...

The Bc mass and lifetime measurements using the exclusive decay Bc -> Jpsi pi at the LHCb experiment were studied. About 300 signal events are expected for a data set which corresponds to an integrated luminosity of 1 fb-1, with a B/S ratio around 2. Based on these data, the Bc mass and lifetime can be measured with expected statistical errors below 2 MeV/c^2 and 30 fs, respectively

I discuss the possibility that the quark model emerges as the lowest order of an hbar expansion of QCD bound states. Bound state calculations are generally complicated by backward (in time) motion of their relativistic constituents (Z-graphs, corresponding to pair production in a time-ordered formulation). I show that in the absence of loops (i.e., at lowest order in hbar) bound state dynamics...

Assuming that the X(3872) is a D0- \bar D0* molecule, we estimate its prompt production cross section at Tevatron and compare our results with the CDF data. We use different hadronization models, namely the ones implemented in Pythia and in Herwig, in order to have an estimate of the associated uncertainties. We give an upper bound for the theoretical cross section and a lower bound for...

In the pure large N Yang-Mills theory there is a quasi BPS sector that is exactly solvable at large N. It follows an exact large N beta function and the glueball spectrum in this sector. The main technical tool is localization of the loop equation for quasi BPS Wilson loops by homological deformations of the loop, somehow in analogy with Witten's cohomological localization by a...

Inelastic Photo-production of J/Psi mesons is studied in ep-scattering at HERA. The J/psi decay angular distributions have been measured with the ZEUS detector, using an integrated luminosity of 468 pb^-1. The range in photon-proton centre-of-mass energy, W, was 50<W<180 GeV. The polar and azimuthal angles of the mu+ were measured in the J/psi rest frame and compared to theoretical...

We give a status report on the recently operating detector BESIII at the BEPCII storage ring. We also present results with the world largest psi(2S) data sample collected with BESIII, including charmonium spectroscopy and decays, and light hadron spectroscopy.

We present evidence for the first observation of electromagnetically bound pion-kaon pairs (piK- atoms) with the DIRAC-II experiment at the CERN-PS. The mean life of piK-atoms is related to the s-wave piK-scattering lengths, a measurement of which is relevant to low energy QCD, in particular chiral perturbation theories including the s-quarks. The atoms are produced by a 24 GeV/c proton beam...

A possible resonance decaying into the D*-proton final state is investigated in deep inelastic scattering at HERA. The data were taken with the H1 detector in the years 2004 to 2007 and correspond to an integrated luminosity of ~348 pb^-1 thus increasing the available data significantly compared to the analysis of HERAI data.