On the <Emphasis Type="Italic">K</Emphasis><Superscript>+</Superscript><Emphasis Type="Italic">d</Emphasis> interaction at low energies

The Kd reactions are considered in the impulse approximationwithNN final-state interactions (FSI) taken into account. Realistic parameters for the KN phase shifts are used. The “quasi-elastic” energy region, in which the elementary KN interaction is predominantly elastic, is considered. The theoretical predictions are compared with the data on the K ⁺ d → K ⁺ pn, K ⁺ d → K⁰ pp, K ⁺ d → K ⁺ d, and K ⁺ d total cross sections. The NN FSI effect in the reaction K ⁺ d → K ⁺ pn has been found to be large. The predictions for the Kd cross sections are also given for slow kaons, produced from ϕ(1020) decays, as the functions of the isoscalar KN scattering length a ₀. These predictions can be used to extract the value of a ₀ from the data. The text was submitted by the authors in English.     

Measurement of dijet production at low <Emphasis Type="Italic">Q</Emphasis><Superscript>2</Superscript> at HERA

Triple differential dijet cross sections in interactions are presented in the region of photon virtualities 2 < Q ² < 80 GeV², inelasticities 0.1 < y < 0.85, jet transverse energies E ^* _{T 1} > 7 GeV, E ^* _{T 2} > 5 GeV, and pseudorapidities . The measurements are made in the centre-of-mass frame, using an integrated luminosity of 57 pb^-1. The data are compared with NLO QCD calculations and LO Monte Carlo programs with and without a resolved virtual photon contribution. NLO QCD calculations fail to describe the region of low Q ² and low jet transverse energies, in contrast to a LO Monte Carlo generator which includes direct and resolved photon interactions with both transversely and longitudinally polarised photons. Initial and final state parton showers are tested as a mechanism for including higher order QCD effects in low E _T jet production.Received: 13 January 2004, Revised: 21 July 2004, Published online: 18 August 2004     

Photoluminescence and EPR of porous silicon formed on <Emphasis Type="Italic">n</Emphasis><Superscript>+</Superscript> and <Emphasis Type="Italic">p</Emphasis><Superscript>+</Superscript> single crystals implanted with boron and phosphorus ions

The effect of combined doping by shallow donor and acceptor impurities on boosting the quantum yield of porous-silicon photoluminescence (PL) in the visible and near IR range was studied using phosphorus and boron ion implantation. Nonuniform doping of samples and subsequent oxidizing annealing were performed before and after porous silicon was formed on silicon single crystals strongly doped by arsenic or boron up to ≈10¹⁹ cm^?3. The concentration of known P_b centers of nonradiative recombination was controlled by electron paramagnetic resonance. It is shown that there is an optimal joined content of shallow donors and acceptors that provides a maximum PL intensity in the vicinity of the red part of the visible spectrum. According to estimates, the PL quantum yield in the transitional n ⁺⁺-p ⁺ or p ⁺⁺-n ⁺ layer of porous silicon increases by two orders of magnitude as compared to that in porous silicon formed on silicon not subjected to ion irradiation.     

Exact Results for Topological Strings on Resolved <Emphasis Type="Italic">Y</Emphasis><Superscript><Emphasis Type="Italic"> p</Emphasis>,<Emphasis Type="Italic">q</Emphasis></Superscript> Singularities

We obtain exact results in α′ for open and closed A-model topological string amplitudes on a large class of toric Calabi-Yau threefolds by using their correspondence with five dimensional gauge theories. The toric Calabi-Yaus that we analyze are obtained as minimal resolution of cones over Y ^p,q manifolds and give rise via M-theory compactification to SU(p) gauge theories on . As an application we present a detailed study of the local case and compute open and closed genus zero Gromov-Witten invariants of the orbifold. We also display the modular structure of the topological wave function and give predictions for higher genus amplitudes. The mirror curve in this case is the spectral curve of the relativistic A ₁ Toda chain. Our results also indicate the existence of a wider class of relativistic integrable systems associated to generic Y ^p,q geometries.     

Restricting Positive Energy Representations of Diff<Superscript>+</Superscript>(<Emphasis Type="Italic">S</Emphasis><Superscript>1</Superscript>) to the Stabilizer of <Emphasis Type="Italic">n</Emphasis> Points

Let G _n ? Diff⁺(S ¹) be the stabilizer of n given points of S ¹. How much information do we lose if we restrict a positive energy representation \(U^c_h\) associated to an admissible pair (c, h) of the central charge and lowest energy, to the subgroup G _n ? The question, and a part of the answer originate in chiral conformal QFT. The value of c can be easily “recovered” from such a restriction; the hard question concerns the value of h. If c ≤ 1, then there is no loss of information, and accordingly, all of these restrictions are irreducible. In this work it is shown that \(U^c_{h}|_{G_n}\) is always irreducible for n =  1 and, if h =  0, it is irreducible at least up to n ≤  3. Moreover, an example is given for c >  2 and certain values of \(h \neq \tilde{h}\) such that \(U^c_{h}|_{G_1}\simeq U^c_{\tilde{h}}|_{G_1}\) . It is also concluded that for these values \(U^c_{h}|_{G_n}\) cannot be irreducible for n ≥  2. For further values of c, h and n, the question is left open. Nevertheless, the example already shows that, on the circle, there are conformal QFT models in which local and global intertwiners are not equivalent.     

Sneutrino production at <Emphasis Type="Italic">e</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">e</Emphasis><Superscript>-</Superscript> linear colliders: addendum to slepton production

Complementing the preceding study of charged scalar leptons, the sector of the neutral scalar leptons, sneutrinos, is investigated in a high-precision analysis for future e ⁺ e ^- linear colliders. The theoretical predictions for the cross-sections are calculated at the thresholds for non-zero widths and in the continuum including higher-order corrections at the one-loop level. Methods for measuring the sneutrino masses and the electron-sneutrino-gaugino Yukawa couplings are presented, addressing theoretical problems specific for the sneutrino channels.Received: 10 September 2004, Revised: 11 October 2004, Published online: 3 March 2005     

Measurement of <Emphasis Type="Italic">K</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">K</Emphasis><Superscript>-</Superscript> production in two-photon collisions in the resonant-mass region

K ⁺ K ^- production in two-photon collisions has been studied using a large data sample of 67 fb^-1 accumulated with the Belle detector at the KEKB asymmetric e ⁺ e ^- collider. We have measured the cross section for the process for center-of-mass energies between 1.4 and 2.4 GeV, and found three new resonant structures in the energy region between 1.6 and 2.4 GeV. The angular differential cross sections have also been measured.Received: 30 September 2003, Published online: 18 December 2003     

Teleportation through <Emphasis Type="Italic">W</Emphasis>-class states

The possibility of using entangled states of the W class either as a quantum channel for teleportation or as states to be teleported is analyzed. The protocols are determined through the unitary transformation of the schemes based on the Greenberger-Horne-Zeilinger (GHZ) channel. It is shown that the main feature of new quantum channels of the W class is a set of nonlocal operators capable of recovering an unknown state.     

Scattering of <Emphasis Type="Italic">W</Emphasis> and <Emphasis Type="Italic">Z</Emphasis> bosons at high-energy lepton colliders

We present a new study of quasi-elastic W and Z scattering processes in high-energy \(e^+e^-\) collisions, based on and extrapolating the low-energy effective theory which extends the standard model with a \(125\;\text {GeV}\) Higgs boson. We parameterize deviations in the low-energy range in terms of the dimension-eight operators that arise in the effective theory. Smoothly extending this to higher energy, we study a set of simplified models of new physics in W / Z scattering, (1) a structureless extrapolation of the effective theory, and (2) scalar and tensor resonance multiplets. The high-energy asymptotics of all models is regulated by a universal unitarization procedure. This enables us to provide benchmark scenarios which can be meaningfully evaluated off shell and in exclusive event samples, and to determine the sensitivity of an \(e^+e^-\) collider to the model parameters. We analyze the longitudinal vector-boson scattering modes, where we optimize the cuts for the fiducial cross section for different collider scenarios. Here, we choose energy stages of 1.0, 1.4 and 3 TeV, as motivated by the extendability of the ILC project and the staging scenario of the CLIC project.     

<Emphasis Type="Italic">Z</Emphasis> <Superscript>+</Superscript>(4430): Nonexotic interpretation

The possibility of describing the charged charmonium-like state Z⁺(4430) as the kinematical rescattering effect is examined. This approach makes it possible to avoid the introduction of exotic hadron states in the model, and one describes structures in the ψ(2S)π⁺ mass spectrum by the presence of the D_s^(*)′ resonance in a hidden intermediate state. The resulting model predictions are compared with the results obtained by the LHCb Collaboration.     

Jet production in charged current deep inelastic <Emphasis Type="Italic">e</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">p</Emphasis> scatteringat HERA

The production rates and substructure of jets have been studied in charged current deep inelastic e ⁺ p scattering for Q ² > 200 GeV² with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb^-1. Inclusive jet cross sections are presented for jets with transverse energies GeV and pseudorapidities in the range . Dijet cross sections are presented for events with a jet having GeV and a second jet having GeV. Measurements of the mean subjet multiplicity, , of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations are compared to the measurements. The value of , determined from at for jets with GeV, is . The mean subjet multiplicity as a function of Q ² is found to be consistent with that measured in NC DIS.Received: 5 June 2003, Published online: 10 October 2003     

Excitation of <Superscript>113<Emphasis Type="Italic">m</Emphasis>,115<Emphasis Type="Italic">m</Emphasis></Superscript>In by positrons

The photonless annihilation cross sections for ^113m,115m In at a boundary positron energy of 3.9 MeV have been measured for the first time: σ^ef(^115m In)=(5.0 ± 0.4) × 10^?27 cm² and σ^ef(^113m In) = (3.4 ± 0.6) × 10^?27 cm². The cross sections obtained differ by four to five orders of magnitude from the calculated values. A new mechanism of consideration of the positrons involved in photonless annihilation is proposed.     

Applying the <Emphasis FontCategory="NonProportional">POWHEG</Emphasis> method to top-pair production and decays at the ILC

We study the effects of gluon radiation in top-pair production and their decays for e ⁺ e ⁻ annihilation at the ILC. To achieve this we apply the POWHEG method and interface our results to the Monte Carlo event generator . We consider a centre-of-mass energy of GeV and compare decay correlations and bottom-quark and -antiquark distributions before hadronisation.     

Constrained path calculations of the <Superscript>4</Superscript><Emphasis Type="Italic">He</Emphasis> and <Superscript>16</Superscript><Emphasis Type="Italic">O</Emphasis> nuclei

We give results for the energy of the ⁴He and ¹⁶O nuclei using the auxiliary field diffusion Monte Carlo and a path constraint. We compare the results with previous FHNC and cluster Monte Carlo calculations.Received: 1 November 2002, Published online: 15 July 2003PACS: 21.10.Dr Binding energies and masses - 21.60.Ka Monte Carlo models     

Contribution of the <Emphasis Type="Italic">M</Emphasis>1 process to the astrophysical <Emphasis Type="Italic">S</Emphasis>-factor of the <Emphasis Type="Italic">p</Emphasis><Superscript>2</Superscript>H radiative capture

The experimental data on the astrophysical S-factor of the p ²H radiative capture are well described for energies from 1 keV to 10 MeV using the potential cluster model and the Young schemes of orbital cluster state classification with allowance for the E1 and M1 transitions.     

Proton production in <Superscript>16</Superscript>O<Emphasis Type="Italic">p</Emphasis> collisions at 3.25 GeV/<Emphasis Type="Italic">c</Emphasis> per nucleon

The momentum features of protons originating as fragments from ¹⁶Op interactions at 3.25 GeV/c per nucleon are analyzed for the first time under conditions of 4π geometry. It is found that the mechanisms of the production of all protons traveling in the forward direction in the rest frame of the fragmenting nucleus (with the exception of evaporated protons) do not depend on either the primary energy or the target-nucleus type, this regularity being quite universal for the formation of such protons. It is shown that there is a strong correlation between the shape of the momentum spectrum of protons appearing as fragments from such interactions, especially slow protons, and the degree of the excitation of the fragmenting nucleus.     

Finite-Time Blow-up of Solutions of an Aggregation Equation in <Emphasis Type="Italic">R</Emphasis><Superscript><Emphasis Type="Italic">n</Emphasis></Superscript>

We consider the aggregation equation in R ⁿ , n ≥ 2, where K is a rotationally symmetric, nonnegative decaying kernel with a Lipschitz point at the origin, e.g. K(x) = e ^−|x|. We prove finite-time blow-up of solutions from specific smooth initial data, for which the problem is known to have short time existence of smooth solutions.     

<Emphasis Type="Italic">Q</Emphasis><Superscript>2</Superscript> evolution of parton densities at smal-<Emphasis Type="Italic">x</Emphasis> values

In the leading twist approximation of the Wilson operator product expansion with “frozen” and analytic strong coupling constants we show that Bessel-inspired behavior of the structure function F ₂ at small x, obtained for a flat initial condition in the DGLAP evolution equations, leads to good agreement with the deep-inelastic scattering experimental data from HERA.     

<Emphasis Type="Italic">f</Emphasis>(<Emphasis Type="Italic">R</Emphasis>) Cosmology from <Emphasis Type="Italic">q</Emphasis>-theory

From a macroscopic theory of the quantum vacuum in terms of conserved relativistic charges (generically denoted by q ^(a) with label a), we have obtained, in the low-energy limit, a particular type of f(R) model relevant to cosmology. The macroscopic quantum-vacuum theory allows us to distinguish between different phenomenological f(R) models on physical grounds. The text was submitted by the authors in English.     

Measurement of high-<Emphasis Type="Italic">Q</Emphasis><Superscript>2</Superscript> charged current cross sections in <Emphasis Type="Italic">e</Emphasis><Superscript> + </Superscript><Emphasis Type="Italic">p</Emphasis> deep inelastic scattering at HERA

Cross sections for e ⁺ p charged current deep inelastic scattering at a centre-of-mass energy of have been determined with an integrated luminosity of collected with the ZEUS detector at HERA. The differential cross sections , and for are presented. In addition, has been measured in the kinematic range and . The predictions of the Standard Model agree well with the measured cross sections. The mass of the W boson propagator is determined to be from a fit to . The chiral structure of the Standard Model is also investigated in terms of the (1-y)² dependence of the double-differential cross section. The structure-function has been extracted by combining the measurements presented here with previous ZEUS results from e ^- p scattering, extending the measurement obtained in a neutrino-nucleus scattering experiment to a significantly higher Q ² region.Received: 17 July 2003, Published online: 12 November 2003 ^a supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) ^b supported by the German Federal Ministry for Education and Research (BMBF), under contract numbers HZ1GUA 2, HZ1GUB 0, HZ1PDA 5, HZ1VFA 5 ^c supported by the MINERVA Gesellschaft für Forschung GmbH, the Israel Science Foundation, the U.S.-Israel Binational Science Foundation and the Benozyio Center for High Energy Physics ^d supported by the German-Israeli Foundation and the Israel Science Foundation ^e supported by the Italian National Institute for Nuclear Physics (INFN) ^f supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research ^g supported by the Korean Ministry of Education and Korea Science and Engineering Foundation ^h supported by the Netherlands Foundation for Research on Matter (FOM) ⁱ supported by the Polish State Committee for Scientific Research, grant no. 620/E-77/SPUB-M/DESY/P-03/DZ 247/2000-2002 ^j partially supported by the German Federal Ministry for Education and Research (BMBF) ^k supported by the Fund for Fundamental Research of Russian Ministry for Science and Education and by the German Federal Ministry for Education and Research (BMBF) ^l supported by the Spanish Ministry of Education and Science through funds provided by CICYT ^m supported by the Particle Physics and Astronomy Research Council, UK ⁿ supported by the US Department of Energy ^o supported by the US National Science Foundation ^p supported by the Polish State Committee for Scientific Research, grant no. 112/E-356/SPUB-M/DESY/P-03/DZ 301/2000-2002, 2 P03B 13922 ^q supported by the Polish State Committee for Scientific Research, grant no. 115/E-343/SPUB-M/DESY/P-03/DZ 121/2001-2002, 2 P03B 07022