101 research outputs found

    EVIDENCE-BASED RELATIONSHIP BETWEEN THE LEVELS OF IL-6, VECF, sFas, FasL AND ENDOSTATIN IN PATIENTS WITH OVARIAN NEOPLASMS

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    The paper deals with the study of the factors that regulate apoptosis and angiogenesis, by using biomolecular methods in patients with ovarian neoplasms. The investigation of these factors will furnish insights into the essence of the abnormalities underlying these diseases

    Photon & Axion Oscillation In a Magnetized Medium: A Covariant Treatment

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    Pseudoscalar particles, with almost zero mass and very weak coupling to the visible matter, arise in many extensions of the standard model of particle physics. Their mixing with photons in the presence of an external magnetic field leads to many interesting astrophysical and cosmological consequences. This mixing depends on the medium properties, the momentum of the photon and the background magnetic field. Here we give a general treatment of pseudoscalar-photon oscillations in a background magnetic field, taking the Faraday term into account. We give predictions valid in all regimes, under the assumption that the frequency of the wave is much higher than the plasma frequency of the medium. At sufficiently high frequencies, the Faraday effect is negligible and we reproduce the standard pseudoscalar-photon mixing phenomenon. However at low frequencies, where Faraday effect is important, the mixing formulae are considerably modified. We explicitly compute the contribution due to the longitudinal mode of the photon and show that it is negligible.Comment: 16 pages, no figure

    libepa -- a C++/Python library for calculations of cross sections of ultraperipheral collisions

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    The library provides a set of C++/Python functions for computing cross sections of ultraperipheral collisions of high energy particles under the equivalent photons approximation. Cross sections are represented through multiple integrals over the phase space. The integrals are calculated through recurrent application of algorithms for one dimensional integration. The paper contains an introduction to the theory of ultraperipheral collisions, discusses the library approach and provides a few examples of calculations.Comment: 25 pages, 6 figures, 1 table. See the arXiv archive for supplementary materials (code

    Weak interaction corrections to muon pair production via the photon fusion at the LHC

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    Analytical formulas describing the correction due to the ZZ boson exchange to the cross section of the reaction pppμ+μXpp\rightarrow p\mu^+\mu^- X are presented. When the invariant mass of the produced muon pair W150 GeVW\gtrsim 150~\text{GeV} and its total transverse momentum is large, the correction is of the order of 20%.Comment: 17 pages, 5 figure

    On production of heavy charged particles in γγ\gamma\gamma fusion at planned pppp colliders

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    Production of heavy fermions in ultraperipheral collisions (ppp+γγ+pp+χ+χ+ppp\to p+\gamma\gamma+p\to p+\chi^{+}\chi^{-}+p) and the semiexclusive reaction (ppp+γγ+Xp+χ+χ+Xpp \to p+\gamma\gamma^{*}+X \to p+\chi^{+}\chi^{-}+X) is considered. Differential and total cross sections for the energies of the planned pppp colliders are presented.Comment: 8 pages, 4 figures, 2 table

    pppp scattering at the LHC with the lepton pair production and one proton tagging

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    Analytical formulas for the cross section of the reaction ppp+++Xpp \to p + \ell^+ \ell^- + X are presented. Fiducial cross sections are compared with those measured recently by the ATLAS collaboration.Comment: 12 pages, 1 figur

    Moderate Supersymmetric CP Violation

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    It is well known that supersymmetry (SUSY) gives neutron and electron electric dipole moments (dnd_n and ded_e) which are too large by about 10310^{3}. If we assume a SUSY model cannot contain fine-tunings or large mass scales, then one must require that the SUSY breaking mechanism give real soft breaking parameters, in which case the minimal SUSY model has no CPCP violation other than from the CKM matrix (besides possible strong CPCP violating effects). We show that in non-minimal SUSY models, a moderate amount of CPCP violation can be induced through one loop corrections to the scalar potential, giving an effective phase of order 10310^{-3}, and thus implying dnd_n and ded_e can be near their current experimental bounds naturallynaturally. This moderate amount of SUSY CPCP violation could also prove important for models of electroweak baryogenesis. We illustrate our results with a specific model.Comment: 19pp plain LATEX, 1 fig (by EMAIL request), TRI-PP-93-86. (Some clarifying comments about renormalizability added--version to appear in Phys. Rev. D

    Cosmological constraints on R-parity violation from neutrino decay

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    If the neutrino mass is non-zero, as hinted by several experiments, then R-parity-violating supersymmetric Yukawa couplings can drive a heavy neutrino decay into lighter states. The heavy neutrino may either decay radiatively into a lighter neutrino, or it may decay into three light neutrinos through a Z-mediated penguin. For a given mass of the decaying neutrino, we calculate its lifetime for the various modes, each mode requiring certain pairs of R-parity-violating couplings be non-zero. We then check whether the calculated lifetimes fall in zones allowed or excluded by cosmological requirements. For the latter case, we derive stringent new constraints on the corresponding products of R-parity-violating couplings for given values of the decaying neutrino mass.Comment: 13 pages, Latex, uses axodraw.sty; version to appear in Physical Review

    Solving the mu problem with a heavy Higgs boson

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    We discuss the generation of the mu-term in a class of supersymmetric models characterized by a low energy effective superpotential containing a term lambda S H_1 H_2 with a large coupling lambda~2. These models generically predict a lightest Higgs boson well above the LEP limit of 114 GeV and have been shown to be compatible with the unification of gauge couplings. Here we discuss a specific example where the superpotential has no dimensionful parameters and we point out the relation between the generated mu-term and the mass of the lightest Higgs boson. We discuss the fine-tuning of the model and we find that the generation of a phenomenologically viable mu-term fits very well with a heavy lightest Higgs boson and a low degree of fine-tuning. We discuss experimental constraints from collider direct searches, precision data, thermal relic dark matter abundance, and WIMP searches finding that the most natural region of the parameter space is still allowed by current experiments. We analyse bounds on the masses of the superpartners coming from Naturalness arguments and discuss the main signatures of the model for the LHC and future WIMP searches.Comment: Extended discussion of the LHC phenomenology, as published on JHEP plus an addendum on the existence of further extremal points of the potential. 47 pages, 16 figure
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