A search for contact interactions has been performed using dimuon events recorded with the ATLAS detector in proton-proton collisions at $\sqrt{s}=7\text{ }\text{ }\mathrm{TeV}$. The data sample corresponds to an integrated luminosity of $42\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$. No significant deviation from the standard model is observed in the dimuon mass spectrum, allowing the following 95% C.L. limits to be set on the energy scale of contact interactions: $\ensuremath{\Lambda}>4.9\text{ }\text{ }\mathrm{TeV}$ (4.5 TeV) for constructive (destructive) interference in the left-left isoscalar compositeness model. These limits are the most stringent to date for $\ensuremath{\mu}\ensuremath{\mu}qq$ contact interactions.

The ATLAS experiment has measured the production cross-section of events with two isolated photons in the final state, in proton-proton collisions at sqrt(s) = 7 TeV. The full data set acquired in 2010 is used, corresponding to an integrated luminosity of 37 pb^-1. The background, consisting of hadronic jets and isolated electrons, is estimated with fully data-driven techniques and subtracted. The differential cross-sections, as functions of the di-photon mass, total transverse momentum and azimuthal separation, are presented and compared to the predictions of next-to-leading-order QCD.

Jet shapes have been measured in inclusive jet production in proton-proton collisions at √s=7 TeV using 3 pb−1 of data recorded by the ATLAS experiment at the LHC. Jets are reconstructed using the anti-kt algorithm with transverse momentum 30 GeV

Comparative data are presented on the radiation stability of die-cast polystyrene scintillator plates and spectrum-shifting fibers irradiated with gamma-quanta and high-energy hadrons.

A search for lepton flavour number violating Z0 decays in the channels Z0 → μτ , Z0 → eτ , Z0 → eμ, using the DELPHI detector with data collected during the 1991–94 LEP runs, is described. No signal was found. Upper limits at 95% confidence level for the respective branching fractions of 1.2× 10−5, 2.2× 10−5, and 0.25× 10−5, were obtained.

A comparative study of the radiation damage caused by γ-quanta and hadron irradiation in polystyrene scintillation tiles produced by the injection molding technique and in wavelength shifting fibers is presented.

The reaction π−p→η′η′n has been studied atpπ=37 GeV/c. Total of 14 events of this reaction have been selected. It has been shown that in the effective mass spectrum of the η′η′ system the events are concentrated mainly near the reaction threshold, which might be caused by the decayX(1910)→η′η′. The reaction cross-section has been evaluated: σ(π−p→η′η′n)=110±40 nb.

The reaction pi-A --> pi-eta'etaA is studied at the momentum 36 GeV/c. In this reaction near the pi-eta'eta threshold an object is observed which decays into pi-f0(1590). A combined analysis of the two channels pi-etaeta and pi-eta'eta gives the following value for the ratio of the decay probabilities: Br (X --> pi-eta'eta)/Br(X --> pi-etaeta) = 0.29 +/- 0.07.

The reactionπ−C→π−η′C has been studied at 36 GeV/c. A clear signal for the decaya 2 − (1320)→π−·′ is observed in theπ−η′ mass spectrum. The measured ratio of branchings is BR (a 2 − →π−η′)/BR(a 2 − →π−η);(3.4±0.8±0.5)·10−2.

The wave with exotic quantum numbers JPC=1−+ is studied in η’π−, ηπ−, f1π−, and ρ0π− systems produced in π−N interactions at pπ−=37 GeV/c in the high‐statistics experiment at IHEP VES setup. The magnitude of JPC=1−+ wave in η’π− system significantly exceeds that in ηπ− system. Resonance‐like structure with mass M=1.62±0.02 GeV and with Γ=0.24±0.05 GeV is observed in ρ0π− system.

The ωω system produced in the reactionπ−p→ωωn atp π − = 36 GeV/c has been studied at the IHEP VES setup. PWA has been performed and characteristics of objects in the wavesJ PC =2++ and 4++ have been determined.

The reaction pi-C --> pi-eta' C has been studied at 36GeV/c. A clear signal for the decay a2- (1320) --> pi-eta' is observed in the pi-eta' mass spectrum. The measured ratio of branchings is BR(a2- --> pi-eta')/BR(a2- --> pi-eta) = (3.4 +/- 0.8 +/- 0.5) .10(-2).

The omega-omega-system produced in the reaction pi-p-->omega-omega-n at p(pi) = 36 GeV/c has been studied at the IHEP VES setup. PWA has been performed and characteristics of objects in the waves J(PC) = 2++ and 4++ have been determined.

The reaction π−N→π−ηηN off a carbon nucleus at Pπ=36 GeV/c has been studied with the help of the wide aperture magnetic spectrometer VES. In the π−ηη system a resonance with M=1814±10 (stat.)±23 (syst.) MeV, Γ=205±18 (stat.)±32 (syst.) MeV has been observed. Its most probable quantum numbers are IG=1+ or 2−.

A search for and investigation of the radiative decays of light mesons D/f1 (1285) --> rho-gamma, rho --> pi+ pi- and eta' --> pi+ pi- gamma was carried out with the "Lepton-F" apparatus. The number of detected events eta' --> pi+ pi- gamma was congruent-to 2000. It is shown that if the dominant contribution to this process comes from the decay channel eta' --> rho-gamma, then the most common methods for describing the rho-peak are not in agreement with the experimental data. Upper bounds (at the 95% confidence level) are found for the branching ratio BR [D/f1 (1285) --> rho-gamma] < 5% and width GAMMA [D/f1 (1285) --> rho-gamma] < 1.25 MeV of the decay D/f1 (1285) --> rho-gamma. The experimental data are compared with the predictions of various theoretical models, and it is concluded that the deviation from the ideal mixing angle in the axial-vector meson nonet is \alpha\ = \theta - theta(ideal)\ > 17-degrees.

The radiative decayη′→π+π−γ has been studied with the statistics of ≃2000 events. Different ways of describingmππ distribution are considered. It is shown that if the dominating contribution to this process is made by the decay channel η′→ργ, then the generally accepted ways of describing the ρ peak do not agree with experimental data.

The D(1285) radiative decay has been observed, 19±5 events of this type have been detected. The branching ratio Br[D(1285)→φγ] = (0.9±0.2±0.4) × 10−3 and the partial width γ [D(1285)→φγ] = 23 ±5±10) keV have been determined. The conclusion has been made that, most probably, the E(1420) meson does not belong to the axial nonet.