Observation of narrow baryon resonance decaying into pKs0pK^0_s in pA-interactions at 70GeV/c70 GeV/c with SVD-2 setup

SVD-2 experiment data have been analyzed to search for an exotic baryon state, the $\Theta^+$-baryon, in a $pK^0_s$ decay mode at $70 GeV/c$ on IHEP accelerator. The reaction $pA \to pK^0_s+X$ with a limited multiplicity was used in the analysis. The $pK^0_s$ invariant mass spectrum shows a resonant structure with $M=1526\pm3(stat.)\pm 3(syst.) MeV/c^2$ and $\Gamma < 24 MeV/c^2$. The statistical significance of this peak was estimated to be of $5.6 \sigma$. The mass and width of the resonance is compatible with the recently reported $\Theta^+$- baryon with positive strangeness which was predicted as an exotic pentaquark ($uudd\bar{s}$) baryon state. The total cross section for $\Theta^+$ production in pN-interactions for $X_F\ge 0$ was estimated to be $(30\div120) \mu b$ and no essential deviation from A-dependence for inelastic events $(\sim A^{0.7})$ was found.Comment: 8 pages, 7 figures, To be submitted to Yadernaya Fizika. v3-v5 - Some references added, minor typos correcte

Nuclear Dependence in Direct Photon Production

We calculate the nuclear dependence of direct photon production in hadron-nucleus collisions. In terms of a multiple scattering picture, we factorize the cross section for direct photon production into calculable short-distance partonic parts times multiparton correlation functions in nuclei. We present the hadron-nucleus cross section as $A^{\alpha}$ times the hadron-nucleon cross section. Using information on the multiparton correlation functions extracted from photon-nucleus experiments, we compute the value of $\alpha$ as a function of transverse momentum of the direct photon. We also compare our results with recent data from Fermilab experiment E706.Comment: 24 pages text in RevTex, 9 Postscript figure

Search for H --> gamma gamma in association with one jet

The discovery potential of ATLAS detector for ${H \to \gamma \gamma}$ is discussed for the case of the Higgs production in association with one jet. The detailed simulation of the signal and the backgrounds was carried out. For signal the different approaches are compared which led to a similar results after the choice of the proper cuts and normalization. The $pp \to \gamma \gamma + jet + X$ background was generated with the exact matrix-elements. The parton-shower, hadronization and detector simulation influence on results was studied. It was found the result dependence with respect to the choice of the parton-showering scale $Q$ for the background. In any case, for \mH = 115 $\div$140~GeV the signal significance was evaluated about or above 5 for an integrated luminosity of 30 fb$^{-1}$

Search for H-->gamgam in association with jets

Search for H-->gamgam in association with jets is discussed. DRAFT ONL