1,100 research outputs found

    Use of transverse beam polarization to probe anomalous VVH interactions at a Linear Collider

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    We investigate use of transverse beam polarization in probing anomalous coupling of a Higgs boson to a pair of vector bosons, at the International Linear Collider (ILC). We consider the most general form of VVH (V = W/Z) vertex consistent with Lorentz invariance and investigate its effects on the process e+ e- --> f bar{f} H, f being a light fermion. Constructing observables with definite CP and naive time reversal (tilde T) transformation properties, we find that transverse beam polarization helps us to improve on the sensitivity of one part of the anomalous ZZH coupling that is odd under CP. Even more importantly it provides the possibility of discriminating from each other, two terms in the general ZZH vertex, both of which are even under CP and tilde T. Use of transverse beam polarization when combined with information from unpolarized and linearly polarized beams therefore, allows one to have completely independent probes of all the different parts of a general ZZH vertex.Comment: 15 pages, 3 figures, published versio

    tt-Covering Arrays Generated by a Tiling Probability Model

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    A t-\a covering array is an m×nm\times n matrix, with entries from an alphabet of size α\alpha, such that for any choice of tt rows, and any ordered string of tt letters of the alphabet, there exists a column such that the "values" of the rows in that column match those of the string of letters. We use the Lov\'asz Local Lemma in conjunction with a new tiling-based probability model to improve the upper bound on the smallest number of columns N=N(m,t,α)N=N(m,t,\alpha) of a t-\a covering array.Comment: 7 page

    Strange freezeout

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    We argue that known systematics of hadron cross sections may cause different particles to freeze out of the fireball produced in heavy-ion collisions at different times. We find that a simple model with two freezeout points is a better description of data than that with a single freezeout, while still remaining predictive. The resulting fits seem to present constraints on the late stage evolution of the fireball, including the tantalizing possibility that the QCD chiral transition influences the yields at sqrt(S)=2700 GeV and the QCD critical point those at sqrt(S)=17.3 GeV

    Fermion Dipole Moments in Supersymmetric Models with Explicitly Broken R-parity

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    We present a simple analysis that allows us to extract the leading mass dependence of the dipole moment of matter fermions that might be induced by new physics. We present explicit results for the supersymmetric model with broken R-parity as an illustration. We show that the extra contributions to the electric dipole moment (edm) of fermions from R-parity violating interactions can occur only at two loop level, contrary to claims in the literature. We further find that unlike the generic lepto-quark models, the extra contributions to the dipole moments of the leptons can only be enhanced by m_b/m_l and not by m_t/m_l relative to the expectations in the Standard Model. An interesting feature about this enhancement of these dipole moments is that it does not involve unknown mixing angles. We then use experimental constraints on the electric dipole moments of electron and neutron to obtain bounds on (the imaginary part of) products of R-parity violating couplings, and show that bounds claimed in the literature are too stringent by many orders of magnitude.Comment: 16 pages latex, 7 figure

    Effects of polarisation on study of anomalous VVH interactions at a Linear Collider

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    We investigate the use of beam polarisation as well as final state τ\tau polarisation effects in probing the interaction of the Higgs boson with a pair of heavy vector bosons in the process e+effˉHe^+ e^- \to f \bar f H, where ff is any light fermion. The sensitivity of the International Linear Collider (ILC) operating at s=500\sqrt s=500 GeV, to such VVHVVH(V=W/ZV = W/Z) couplings is examined in a model independent way. The effects of ISR and beamstrahlung are discussed.Comment: To appear in the proceedings of 2007 International Linear Collider Workshop (LCWS07 and ILC07), Hamburg, Germany, 30 May - 3 Jun 2007. 4 pages, LaTeX, 1 eps figure. requires ilcws07.cls. included in submissio

    Biodegradation of polymers and isolation and crude characterization of proteins from these studies

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    The performance of immobilized and free microorganisms in the biodegradation of polymers was investigated using a recirculation flow reactor and an air-sparged reactor respectively. The bio-oxidation ability of these microbes towards polyamide emulsion was studied. Extracellular protein cuts isolated were checked for oxidative activity in a microassay reactor. These fractions were compared from various biodegradation studies. Microassay tests and monitoring of the oxygen consumption in recirculation flow confirmed substrate dependent oxygen consumption, polyamide being provided as the sole carbon source. Increases in extracellular protein buildup were a positive indication of biodegradation. The protein cut greater than 500,000 daltons was found to be the most active (highest specific activity) and catalase and oxidase were found to be two of the enzymes in the extracellular protein mix

    γγ\gamma \gamma Processes at High Energy pp Colliders

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    In this note we investigate the production of charged heavy particles via \gaga\ fusion at high energy pp colliders. We revise previous claims that the \gaga\ cross section is comparable to or larger than that for the corresponding Drell-Yan process at high energies. Indeed we find that the \gaga\ contribution to the total production cross section at pp is far below the Drell-Yan cross section. As far as the individual elastic, semi-elastic and inelastic contributions to the \gaga\ process are concerned we find that they are all of the same order of magnitude.Comment: REVTEX, 12 pages, two uuencoded figures appended at the end of the fil
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