152 research outputs found

    On the numerical closeness of the effective phenomenological electroweak mixing angle θ\theta and the \MS parameter θ^\hat\theta

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    It happens that s2s^2 and s^2\hat s^2 are equal with 0.1% accuracy, though they are split by radiative corrections and a natural estimate for their difference is 1%. This degeneracy occurs only for mtm_t value close to 170\GeV, so no deep physical reason can be attributed to it. However, another puzzle of the Standard Model, the degeneracy of s_\Eff^2 and s2s^2, is not independent of the previous one since a good physical reason exists for s_\Eff^2 and s^2\hat s^2 degeneracy. We present explicit formulas which relate these three angles.Comment: 10 pages, latex, 3 figures included; published on MPLA. A few numerical estimates are improved; journal-ref is adde

    QCD Corrections to Electroweak Annihilation Decays of Superheavy Quarkonia

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    QCD corrections to all the allowed decays of superheavy groundstate quarkonia into electroweak gauge and Higgs bosons are presented. For quick estimates, approximations that reproduce the exact results within less than at worst two percent are also given.Comment: 20 pages RevTeX, 9 figures. The complete paper, including figures, is also available via anonymous ftp at (129.13.102.139) as ftp://ttpux2.physik.uni-karlsruhe.de/ttp95-05/ttp95-05.ps, or via www at http://ttpux2.physik.uni-karlsruhe.de/cgi-bin/preprints

    Binary systems of neutral mesons in Quantum Field Theory

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    Quasi-degenerate binary systems of neutral mesons of the kaon type are investigated in Quantum Field Theory (QFT). General constraints cast by analyticity and discrete symmetries P, C, CP, TCP on the propagator (and on its spectral function) are deduced. Its poles are the physical masses; this unambiguously defines the propagating eigenstates. It is diagonalized and its spectrum thoroughly investigated. The role of ``spurious'' states, of zero norm at the poles, is emphasized, in particular for unitarity and for the realization of TCP symmetry. The K_L-K_S mass splitting triggers a tiny difference between their CP violating parameters \epsilon_L and \epsilon_S, without any violation of TCP. A constant mass matrix like used in Quantum Mechanics (QM) can only be introduced in a linear approximation to the inverse propagator, which respects its analyticity and positivity properties; it is however unable to faithfully describe all features of neutral mesons as we determine them in QFT, nor to provide any sensible parameterization of eventual effects of TCP violation. The suitable way to diagonalize the propagator makes use of a bi-orthogonal basis; it is inequivalent to a bi-unitary transformation (unless the propagator is normal, which cannot occur here). Problems linked with the existence of different ``in'' and ``out'' eigenstates are smoothed out. We study phenomenological consequences of the differences between the QFT and QM treatments. The non-vanishing of semi-leptonic asymmetry \delta_S - \delta_L does not signal, unlike usually claimed, TCP violation, while A_TCP keeps vanishing when TCP is realized. We provide expressions invariant by the rephasing of K0 and K0bar.Comment: 44 pages, 2 figures. Version to appear in Int. J. Mod. Phys.

    Quarkonium production in SM Higgs decays

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    We investigate the SM Higgs decays into heavy quarkonia J/\psi and \Upsilon in both color-singlet and color-octet mechanisms. It is found that in J/\psi production the contribution through color-octet processes overwhelm that in color-singlet processes all the intermediate region M_Z<M_{H^0}<2 M_w and the fraction ratio is comparatively large, but in \Upsilon production the contribution through color-octet mechanism is negligible.Comment: 9 pages, LaTex, 4 postscript figures. To appear in Journal of Physics

    Macro- and microelements determination in children with rotavirus infection

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    The purpose of this study was to determine serum zinc, iron, magnesium, copper, potassium, calcium, and sodium levels in acute rotavirus infection and convalescence period in children. Materials and methods. We examined 86 patients aged from 4 months to 5 years with clinical and laboratory signs of rotavirus infection. The I group – 43 children with RVI in acute period. The II group – 43 children with RVI in convalescence period. The control group included 14 healthy children at the same age. The content of macro- and microelements (zinc, iron, magnesium, copper, potassium, calcium and sodium) in blood serum was determined by atomic absorption spectrophotometry. Feces samples were used for Cito Test Rota (Pharmasco). Cito test was used for rotavirus antigen detection in feces. Statistical analysis was performed by Excel. Student’s t-test was used to evaluate differences between study groups. Results. The acute period of the disease in children with rotavirus infection was characterized by a significant increase of copper in blood serum compared with the control group. At the same time, a significant decrease of iron, magnesium, zinc, potassium, calcium, sodium were determined in patients with rotavirus infection, compared with apparently healthy children. After standard treatment only the indicators of magnesium, potassium and sodium reached the same indices of control group children. Conclusions. The detected changes in the mineral status of patients with rotavirus infection suggest the need for treatment correction. Correction of micro- and macroelements imbalances in patients with rotavirus infection possibly should be aimed at the metallo-drugs inclusion in complex treatment as well as medicines which improve absorption of the latter in the intestine

    Conference of Soviet and American Jurists on the Law of the Sea and the Protection of the Marine Environment

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    Included in the papers for the Conference of Soviet and American Jurists on the Law of the Sea and the Protection of the Marine Environment: Introduction by Milton Katz and Richard R. Baxter, p. 1 Freedom of Scientific Research in the World Ocean by A.F. Vysotsky, p. 7 The International Law of Scientific Research in the Oceans by Richard R. Baxter, p. 27 Responsibility and Liability for Harm to the Marine Environment by Robert E. Stein, p. 41 Liability for Marine Environment Pollution Damage in Contemporary International Sea Law by A. L. Makovsky, p. 59 Protection of the Marine Environment from Pollution by Richard A. Frank, p. 73 The Freedom of Navigation and the Problem of Pollution of the Marine Environment by V. A. Kiselev, p. 93 The Freedom of Navigation Under International Law by William E. Butler, p. 107 International Fisheries Management Without Global Agreement: United States Policies and Their Impact on the Soviet Union by H. Gary Knight, p. 119 Some Biological Background for International Legal Acts on Rational Utilization of the Living Resources of the World Ocean by P. A. Moiseev, p. 143 An International Regime for the Seabed Beyond National Jurisdiction by Thomas M. Franck, p. 151 Settlement of Disputes Under the Law of Ocean Use, with Particular Reference to Environmental Protection by John Lawrence Hargrove, p. 18

    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

    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
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