8,062 research outputs found

    Solar cell cover glass development Final report

    Get PDF
    High vacuum ion beam sputtering of integral coverslips for solar cell utilizatio

    Enhanced Molecular Orientation Induced by Molecular Anti-Alignment

    Get PDF
    We explore the role of laser induced anti-alignment in enhancing molecular orientation. A field-free enhanced orientation via anti-alignment scheme is presented, which combines a linearly polarized femtosecond laser pulse with a half-cycle pulse. The laser pulse induces transient anti-alignment in the plane orthogonal to the field polarization, while the half-cycle pulse leads to the orientation. We identify two qualitatively different enhancement mechanisms depending on the pulse order, and optimize their effects using classical and quantum models both at zero and non-zero temperature

    The Small-x Behaviour of the Singlet Polarized Structure Function g_2 in the Double Logarithmic Approximation

    Get PDF
    The small-x behavior of the singlet contributions to the polarized structure function g_2(x,Q^2) is calculated in the double-logarithmic approximation of perturbative QCD. The dominant contribution is due to the gluons which, in contrast to the unpolarized case, mix with the fermions also in the small-x domain. We find a power-like growth in 1/x in the odd-signature parts of the amplitude with the same power as in the singlet function g_1(x,Q^2) at x<< 1.Comment: 20 pages, latex, 3 ps figure

    Three Jet Events and New Strong Couplings at LEP and NLC

    Get PDF
    We study the effects of new dimension--6 operators, resulting from a general SU(3)CSU(2)LU(1)YSU(3)_C \otimes SU(2)_L \otimes U(1)_Y invariant effective Lagrangian, on three jet production at LEP and at the Next Linear Collider. Contributions to the total event rate and to some event shape variables are analysed in order to establish bounds on these operators.Comment: 5 pages, LaTeX, 1 Figur

    High Energy Quark-Antiquark Elastic scattering with Mesonic Exchange

    Full text link
    We studies the high energy elastic scattering of quark anti-quark with an exchange of a mesonic state in the tt channel with t/Λ21-t/\Lambda^{2} \gg 1. Both the normalization factor and the Regge trajectory can be calculated in PQCD in cases of fixed (non-running) and running coupling constant. The dependence of the Regge trajectory on the coupling constant is highly non-linear and the trajectory is of order of 0.20.2 in the interesting physical range.Comment: 29 page

    Spin constraints on Regge predictions and perturbative evolution in high energy collisions

    Get PDF
    Two key issues in the application of perturbative QCD and Regge predictions to high energy processes are whether the hard and soft pomerons should be considered as two separate distinct exchanges and whether the Regge intercepts are Q^2 independent or not. Models involving a distinct hard pomeron exchange predict much larger values for the LHC total cross-section. Here we argue that there is a polarized analogue of this issue in the isovector part of the spin structure function g_1 and that the spin data appear to favour a distinct hard exchange.Comment: 8 page

    Inclusive production of a pair of hadrons separated by a large interval of rapidity in proton collisions

    Full text link
    We consider within QCD collinear factorization the inclusive process p+ph1+h2+Xp+p\to h_1+h_2+X, where the pair of identified hadrons, h1,h2h_1,h_2, having large transverse momenta is produced in high-energy proton-proton collisions. In particular, we concentrate on the kinematics where the two identified hadrons in the final state are separated by a large interval of rapidity Δy\Delta y. In this case the (calculable) hard part of the reaction receives large higher order corrections αsnΔyn\sim \alpha^n_s \Delta y^n. We provide a theoretical input for the resummation of such contributions with next-to-leading logarithmic accuracy (NLA) in the BFKL approach. Specifically, we calculate in NLA the vertex (impact-factor) for the inclusive production of the identified hadron. This process has much in common with the widely discussed Mueller-Navelet jets production and can be also used to access the BFKL dynamics at proton colliders. Another application of the obtained identified-hadron vertex could be the NLA BFKL description of inclusive forward hadron production in DIS.Comment: 29 pages, 9 figures; corrected few typos and added an acknowledgment; version to be published on JHEP. arXiv admin note: substantial text overlap with arXiv:1202.108

    Saturation Effects in Deep Inelastic Scattering at low Q2Q^2 and its Implications on Diffraction

    Full text link
    We present a model based on the concept of saturation for small Q2Q^2 and small xx. With only three parameters we achieve a good description of all Deep Inelastic Scattering data below x=0.01x=0.01. This includes a consistent treatment of charm and a successful extrapolation into the photoproduction regime. The same model leads to a roughly constant ratio of diffractive and inclusive cross section.Comment: 24 pages, 12 figures, Latex-fil

    Orienting coupled quantum rotors by ultrashort laser pulses

    Get PDF
    We point out that the non-adiabatic orientation of quantum rotors, produced by ultrashort laser pulses, is remarkably enhanced by introducing dipolar interaction between the rotors. This enhanced orientation of quantum rotors is in contrast with the behavior of classical paired rotors, in which dipolar interactions prevent the orientation of the rotors. We demonstrate also that a specially designed sequence of pulses can most efficiently enhances the orientation of quantum paired rotors.Comment: 7 pages, 5 figures, to appear in Phys. Rev.
    corecore