8,368 research outputs found

    Energy Level Diagrams for Black Hole Orbits

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    A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy to atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy, and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.Comment: 8 page

    On signals of new physics in global event properties in pp collisions in the TeV energy domain

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    In the framework of the weighted superposition mechanism of different classes of minimum bias events (or substructures), described by the negative binomial multiplicity distribution, in possible scenarios for pp collisions in the TeV energy domain, we explore global properties of an eventual new class of events, characterised by high hadron and clan densities, to be added to the soft (without minijets) and semihard (with minijets) ones. It turns out that the main signal of the mentioned new physical expectations at 14 TeV c.m. energy would be an ``elbow structure'' in the tail of the total charged particle multiplicity distribution in complete disagreement with the second shoulder structure predicted by Pythia Monte Carlo calculations: a challenging problem for new experimental work.Comment: 14 pages, 6 ps figures include

    Effective Hamiltonian Approach to Hyperon Beta Decay with Final-State Baryon Polarization

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    Using an effective Hamiltonian approach, we obtain expressions for hyperon beta decay final-state baryon polarization. Terms through second order in the energy release are retained. The resulting approximate expressions are much simpler and more compact than the exact expressions, and they agree closely with them.Comment: 1 Figure Will appear in Phys Rev D 60 Article 117505 (Dec 1, 1999

    Prompt photon and associated heavy quark production at hadron colliders with kt-factorization

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    In the framework of the kt-factorization approach, the production of prompt photons in association with a heavy (charm or beauty) quarks at high energies is studied. The consideration is based on the O(\alpha \alpha_s^2) off-shell amplitudes of gluon-gluon fusion and quark-(anti)quark interaction subprocesses. The unintegrated parton densities in a proton are determined using the Kimber-Martin-Ryskin prescription. The analysis covers the total and differential cross sections and extends to specific angular correlations between the produced prompt photons and muons originating from the semileptonic decays of associated heavy quarks. Theoretical uncertainties of our evaluations are studied and comparison with the results of standard NLO pQCD calculations is performed. Our numerical predictions are compared with the recent experimental data taken by the D0 and CDF collaborations at the Tevatron. Finally, we extend our results to LHC energies.Comment: 14 pages, 10 figure

    The exclusive B_s -> phi mu+ mu- process in a constituent quark model

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    We consider the exclusive B_s -> phi mu+ mu- process in the standard model using a constituent quark loop model approach together with a simple parameterization of the quark dynamics. The model allows to compute the decay form factors and therefore can give predictions for the decay rates, the invariant mass spectra and the asymmetries. This process is suppressed in the standard model but can be enhanced if new physics beyond the standard model is present, such as flavor-violating supersymmetric models. It constitutes therefore an interesting precision test of the standard model at forthcoming experiments.Comment: 17 pages, 6 figures, 5 tables, LaTeX; minor changes to the introduction, table III and figure 3. Few references adde

    Squark Mixing in Electron-Positron Reactions

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    Squark mixing plays a large role in the phenomenology of the minimal supersymmetric standard model, determining the mass of the lightest Higgs boson and the electroweak interactions of the squarks themselves. We examine how mixing may be investigated in high energy e+ee^+ e^- reactions, both at LEP-II and the proposed linear collider. In particular, off-diagonal production of one lighter and one heavier squark allows one to measure the squark mixing angle, and would allow one to test the mass relations for the light Higgs boson. In some cases off-diagonal production may provide the best prospects to discover supersymmetry. In the context of the light bottom squark scenario, we show that existing data from LEP-II should show definitive evidence for the heavier bottom squark provided that its mass mb~2120m_{\tilde{b}_2} \le 120 GeV.Comment: 22 pages, latex, 6 figure

    The Ratio of W + N jets To Z/gamma + N jets As a Precision Test of the Standard Model

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    We suggest replacing measurements of the individual cross-sections for the production of W + N jets and Z/gamma + N jets in searches for new high-energy phenomena at hadron colliders by the precision measurement of the ratios (W+0 jet)/(Z+0 jet), (W+1 jet)/(Z+1 jet), (W+2 jets)/(Z+2 jets),... (W+N jets)/(Z+N jets), with N as large as 6 (the number of jets in ttbarH). These ratios can also be formed for the case where one or more of the jets is tagged as a b or c quark. Existing measurements of the individual cross sections for Wenu + N jets at the Tevatron have systematic uncertainties that grow rapidly with N, being dominated by uncertainties in the identification of jets and the jet energy scale. These systematics, and also those associated with the luminosity, parton distribution functions (PDF's), detector acceptance and efficiencies, and systematics of jet finding and b-tagging, are expected to substantially cancel in calculating the ratio of W to Z production in each N-jet channel, allowing a greater sensitivity to new contributions in these channels in Run II at the Tevatron and at the LHC.Comment: 10 pages, 8 figures, added reference

    Electroweak and finite width corrections to top quark decays into transverse and longitudinal W W -bosons

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    We calculate the electroweak and finite width corrections to the decay of an unpolarized top quark into a bottom quark and a W W -gauge boson where the helicities of the W W are specified as longitudinal, transverse-plus and transverse-minus. Together with the O(αs) O(\alpha_s) corrections these corrections may become relevant for the determination of the mass of the top quark through angular decay measurements.Comment: 4 pages, 7 postscript figures adde

    Three Numerical Puzzles and the Top Quark's Chiral Weak-Moment

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    Versus the standard model's t --> W b decay helicity amplitudes, three numerical puzzles occur at the 0.1 % level when one considers the amplitudes in the case of an additional (f_M + f_E) coupling of relative strength 53 GeV. The puzzles are theoretical ones which involve the t --> W b decay helicity amplitudes in the two cases, the relative strength of this additional coupling, and the observed masses of these three particles. A deeper analytic realization is obtained for two of them. Equivalent realizations are given for the remaining one. An empirical consequence of these analytic realizations is that it is important to search for effects of a large chiral weak-moment of the top-quark, the effective mass-scale is about 53 GeV. A full theoretical resolution would include relating the origin of such a chiral weak-moment and the mass generation of the top-quark, the W-boson, and probably the b-quark.Comment: 18 pages, 1 postscript table (revised to better explain notation, model #1, add a little material...

    Inclusive Higgs boson and dijet production via Double Pomeron exchange

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    We evaluate Higgs boson and dijet cross-sections at the Tevatron collider via Double Pomeron exchange when accompanying particles in the central region are taken into account. Such {\it inclusive} processes, normalized to the observed dijet rate observed at run I, noticeably increase the predictions for tagged (anti)protons in the run II with respect to {\it exclusive} ones, with the potentiality of Higgs boson detection.Comment: 6pages, 4 figure
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