4,363 research outputs found

    Multipliers for p-Bessel sequences in Banach spaces

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    Multipliers have been recently introduced as operators for Bessel sequences and frames in Hilbert spaces. These operators are defined by a fixed multiplication pattern (the symbol) which is inserted between the analysis and synthesis operators. In this paper, we will generalize the concept of Bessel multipliers for p-Bessel and p-Riesz sequences in Banach spaces. It will be shown that bounded symbols lead to bounded operators. Symbols converging to zero induce compact operators. Furthermore, we will give sufficient conditions for multipliers to be nuclear operators. Finally, we will show the continuous dependency of the multipliers on their parameters.Comment: 17 page

    Yukawa Coupling Unification in Supersymmetric Models

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    We present an updated assessment of the viability of t-b-tau Yukawa coupling unification in supersymmetric models. For the superpotential Higgs mass parameter mu>0, we find unification to less than 1% is possible, but only for GUT scale scalar mass parameter m_{16}~8-20 TeV, and small values of gaugino mass m_{1/2}<400 GeV. Such models require that a GUT scale mass splitting exists amongst Higgs scalars with m_{H_u}^2<m_{H_d}^2. Viable solutions lead to a radiatively generated inverted scalar mass hierarchy, with third generation and Higgs scalars being lighter than other sfermions. These models have very heavy sfermions, so that unwanted flavor changing and CP violating SUSY processes are suppressed, but may suffer from some fine-tuning requirements. While the generated spectra satisfy b->s gamma and (g-2)_mu constraints, there exists tension with the dark matter relic density unless m_{16}<3 TeV. These models offer prospects for a SUSY discovery at the Fermilab Tevatron collider via the search for chargino_1 neutralino_2 -> 3 leptons events, or via gluino pair production. If mu<0, Yukawa coupling unification to less than 5% can occur for m_{16} and m_{1/2}>1-2 TeV. Consistency of negative mu Yukawa unified models with b->s gamma, (g-2)_mu, and relic density all imply very large values of m_{1/2} typically greater than about 2.5 TeV, in which case direct detection of sparticles may be a challenge even at the LHC.Comment: 38 pages, 15 figures. Fig.15 changed, some references were added. A copy of the paper with better resolution figures can be found at http://www.hep.fsu.edu/~balazs/Physics/Papers/2003

    Quantum Mechanics of Damped Systems II. Damping and Parabolic Potential Barrier

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    We investigate the resonant states for the parabolic potential barrier known also as inverted or reversed oscillator. They correspond to the poles of meromorphic continuation of the resolvent operator to the complex energy plane. As a byproduct we establish an interesting relation between parabolic cylinder functions (representing energy eigenfunctions of our system) and a class of Gel'fand distributions used in our recent paper.Comment: 14 page

    Next-to-next-to-leading logarithmic corrections at small transverse momentum in hadronic collisions

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    We study the region of small transverse momenta in qqbar- and gg-initiated processes with no colored particle detected in the final state. We present the universal expression of the O(alpha_s^2) logarithmically enhanced contributions up to next-to-next-to-leading logarithmic accuracy. From there we extract the coefficients that allow the resummation of the large logarithmic contributions. We find that the coefficient known in the literature as B^{(2)} is process dependent, since it receives a hard contamination from the one loop correction to the leading order subprocess. We present the general result of B^{(2)} for both quark and gluon channels. In particular, in the case of Higgs production, this result will be relevant to improve the matching between resummed predictions and fixed order calculations.Comment: LaTeX, 8 pages. Few typos corrected, particularly Eq.(25). Two references added, to be published in PR

    Effects of Dirac sea polarization on hadronic properties - A chiral SU(3) approach

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    The effect of vacuum fluctuations on the in-medium hadronic properties is investigated using a chiral SU(3) model in the nonlinear realization. The effect of the baryon Dirac sea is seen to modify hadronic properties and in contrast to a calculation in mean field approximation it is seen to give rise to a significant drop of the vector meson masses in hot and dense matter. This effect is taken into account through the summation of baryonic tadpole diagrams in the relativistic Hartree approximation (RHA), where the baryon self energy is modified due to interactions with both the non-strange (σ)(\sigma) and the strange (ζ)(\zeta) scalar fields.Comment: 25 pages including 13 figures,figure styles modified,few clarifying sentences added in text, to appear in Phys. Rev.

    Vectored immunoprophylaxis protects humanized mice from mucosal HIV transmission

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    Background: Recently, a number of antibodies capable of broadly neutralizing HIV have been isolated from HIV infected patients, stimulating efforts to develop vaccines capable of eliciting their production in naive individuals. As an alternative to vaccination, we recently described vectored immunoprophylaxis (VIP) as an approach capable of generating high serum concentrations of a desired monoclonal antibody in mice following a single intramuscular injection of a specialized adeno associated viral vector (AAV). Mice that received VIP encoding b12 and VRC01 antibodies demonstrated long-term circulating antibody expression in serum, and VIP-treated humanized mice exhibited remarkable protection against high dose, intravenous challenge with CXCR4-tropic HIV. However, most human infections are initiated by transmission of CCR5- tropic strains through mucosal tissues. Methods: To measure the efficacy of VIP against clinically relevant strains, we humanized VIP-treated mice by adoptive transfer of peripheral blood mononuclear cells (PBMC) and challenged these animals with CCR5-tropic HIV strains including JR-CSF, as well as REJO.c, a transmitted molecular founder. To determine the ability of VIP to prevent mucosal transmission of HIV, we developed a repetitive intravaginal challenge model in VIP-treated BLT humanized mice that were challenged weekly with JR-CSF and monitored for infection. Results: PBMC humanized mice expressing either b12 or VRC01 were protected from intravenous challenge with JR-CSF. In contrast, the b12-resistant REJO.c strain readily infected PBMC humanized mice expressing b12 antibody, while mice expressing VRC01 demonstrated nearly complete protection following challenge. Intravaginally challenged BLT animals expressing a luciferase negative control protein all became infected over the study period while a majority of animals expressing VRC01 had no detectable HIV infection despite fourteen intravaginal challenges with JR-CSF. Conclusion: VIP is capable of protecting humanized mice from challenge by diverse HIV strains and can substantially inhibit mucosal transmission. These findings warrant continued development of VIP as a novel approach for HIV prevention in humans

    Statistics of dressed modes in a thermal state

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    By a Wigner-function calculation, we evaluate the trace of a certain Gaussian operator arising in the theory of a boson system subject to both finite temperature and (weak) interaction. Thereby we rederive (and generalize) a recent result by Kocharovsky, Kocharovsky, and Scully [Phys. Rev. A, vol. 61, art. 053606 (2000)] in a way that is technically much simpler. One step uses a special case of the response of Wigner functions to linear transformations, and we demonstrate the general case by simple means. As an application we extract the counting statistics for each mode of the Bose gas.Comment: to appear in Optics Communications, 10 page

    Frame Theory for Signal Processing in Psychoacoustics

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    This review chapter aims to strengthen the link between frame theory and signal processing tasks in psychoacoustics. On the one side, the basic concepts of frame theory are presented and some proofs are provided to explain those concepts in some detail. The goal is to reveal to hearing scientists how this mathematical theory could be relevant for their research. In particular, we focus on frame theory in a filter bank approach, which is probably the most relevant view-point for audio signal processing. On the other side, basic psychoacoustic concepts are presented to stimulate mathematicians to apply their knowledge in this field

    Differential Cross Section for Higgs Boson Production Including All-Orders Soft Gluon Resummation

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    The transverse momentum QTQ_T distribution is computed for inclusive Higgs boson production at the energy of the CERN Large Hadron Collider. We focus on the dominant gluon-gluon subprocess in perturbative quantum chromodynamics and incorporate contributions from the quark-gluon and quark-antiquark channels. Using an impact-parameter bb-space formalism, we include all-orders resummation of large logarithms associated with emission of soft gluons. Our resummed results merge smoothly at large QTQ_T with the fixed-order expectations in perturbative quantum chromodynamics, as they should, with no need for a matching procedure. They show a high degree of stability with respect to variation of parameters associated with the non-perturbative input at low QTQ_T. We provide distributions dσ/dydQTd\sigma/dy dQ_T for Higgs boson masses from MZM_Z to 200 GeV. The average transverse momentum at zero rapidity yy grows approximately linearly with mass of the Higgs boson over the range MZ<mh≃0.18mh+18M_Z < m_h \simeq 0.18 m_h + 18 ~GeV. We provide analogous results for ZZ boson production, for which we compute ≃25 \simeq 25 GeV. The harder transverse momentum distribution for the Higgs boson arises because there is more soft gluon radiation in Higgs boson production than in ZZ production.Comment: 42 pages, latex, 26 figures. All figures replaced. Some changes in wording. Published in Phys. Rev. D67, 034026 (2003
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