5,802 research outputs found

    A Comparative Study of the Decays B(K,K)+B \to (K,K^*) \ell^+ \ell^- in Standard Model and Supersymmetric Theories

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    Using improved theoretical calculations of the decay form factors in the Light Cone-QCD sum rule approach, we investigate the decay rates, dilepton invariant mass spectra and the forward-backward (FB) asymmetry in the decays B(K,K)+B \to (K,K^*) \ell^+ \ell^- (±=e±,μ±,τ±\ell^\pm =e^\pm,\mu^\pm,\tau^\pm) in the standard model (SM) and a number of popular variants of the supersymmetric (SUSY) models. Theoretical precision on the differential decay rates and FB-asymmetry is estimated in these theories taking into account various parametric uncertainties. We show that existing data on BXsγB \to X_s \gamma and the experimental upper limit on the branching ratio B(BKμ+μ){\cal B}(B \to K^* \mu^+ \mu^-) provide interesting bounds on the coefficients of the underlying effective theory. We argue that the FB-asymmetry in BK+B \to K^* \ell^+ \ell^- constitutes a precision test of the SM and its measurement in forthcoming experiments may reveal new physics. In particular, the presently allowed large-tanβ\tan \beta solutions in SUGRA models, as well as more general flavor-violating SUSY models, yield FB-asymmetries which are characteristically different from the corresponding ones in the SM.Comment: 36 pages, 12 figures (require epsfig.sty), 8 Tables, LaTeX2e; subsection 6.4 corrected, minor changes in numerical results, Figures 3 and 9 to 12 modified; submitted to Physical Review

    Subtleties in the beta function calculation of N=1 supersymmetric gauge theories

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    We investigate some peculiarities in the calculation of the two-loop beta-function of N=1N=1 supersymmetric models which are intimately related to the so-called "Anomaly Puzzle". There is an apparent paradox when the computation is performed in the framework of the covariant derivative background field method. In this formalism, it is obtained a finite two-loop effective action, although a non-null coefficient for the beta-function is achieved by means of the renormalized two-point function in the background field. We show that if the standard background field method is used, this two-point function has a divergent part which allows for the calculation of the beta-function via the renormalization constants, as usual. Therefore, we conjecture that this paradox has its origin in the covariant supergraph formalism itself, possibly being an artifact of the rescaling anomaly.Comment: Few misprintings corrected and comments added. To meet the version to be published at European Physical Journal

    Age, Sex, and Nest Success of Translocated Mountain Quail in Oregon, 2001–2010

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    We trapped mountain quail (Oreortyx pictus) from relatively abundant populations in southwestern Oregon for re-introduction or augmentation in areas of central and eastern Oregon where they were rare or extirpated. We captured 2,596 mountain quail during 2001–2010 using treadle-style traps, of which 1,430 were released in Oregon; the remaining birds were transferred to Idaho, Nevada, and Washington. Yearlings (hatch-year) comprised 69.6% of the total (n 1⁄4 2,596). Analysis of nuclear DNA from 850 captured quail revealed 50.5% were male. We radiomarked 800 (55.9%) of the quail released in Oregon and monitored them to estimate reproductive success. We located 150 nests in Oregon; at least 1 egg hatched in 110 (73.3%) nests. Average (6 SE) clutch size was 10.2 6 0.2 eggs and average number of chicks hatched from successful nests was 8.3 6 0.3. Sixty-eight nests (45.3%) were incubated exclusively by males, 78 (52.0%) exclusively by females, and 4 (2.7%) by birds of unknown gender. Males incubated slightly larger clutches (11.0 6 0.3) and hatched more eggs than females (5.5 6 0.5). Males also regularly contributed to brood-rearing. The reproductive effort and nest success of translocated mountain quail was comparable to native populations in Oregon. Translocations may be an effective means of restoring mountain quail populations that have been extirpated or augmenting populations that have substantially declined

    Predictions for BKγγB \to K \gamma \gamma decays

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    We present a phenomenological study of the rare double radiative decay BKγγB\to K \gamma\gamma in the Standard Model (SM) and beyond. Using the operator product expansion (OPE) technique, we estimate the short-distance (SD) contribution to the decay amplitude in a region of the phase space which is around the point where all decay products have energy mb/3\sim m_b/3 in the rest frame of the BB-meson. At lowest order in 1/Q, where QQ is of order mbm_b, the BKγγB\to K \gamma\gamma matrix element is then expressed in terms of the usual BKB\to K form factors known from semileptonic rare decays. The integrated SD branching ratio in the SM in the OPE region turns out to be ΔB(BKγγ)SMOPE1×109\Delta {\cal{B}}(B \to K \gamma \gamma)_{SM}^{OPE} \simeq 1 \times 10^{-9}. We work out the di-photon invariant mass distribution with and without the resonant background through BK{ηc,χc0}KγγB\to K \{\eta_c,\chi_{c0}\}\to K\gamma \gamma. In the SM, the resonance contribution is dominant in the region of phase space where the OPE is valid. The present experimental upper limit on Bsτ+τB_s \to \tau^+ \tau^- decays, which constrains the scalar/pseudoscalar Four-Fermi operators with τ+τ\tau^+ \tau^-, leaves considerable room for new physics in the one-particle-irreducible contribution to BKγγB\to K \gamma \gamma decays. In this case, we find that the SD BKγγB\to K \gamma \gamma branching ratio can be enhanced by one order of magnitude with respect to its SM value and the SD contribution can lie outside of the resonance peaks.Comment: 17 pages, 4 figures; Note added on Schouten identity and 2 references added; v4: typos in Eqs (8), (44) and erroneous statement on mixing before Eq (44) fixed. All results and conclusions unchange

    Symmetries and Ambiguities in the linear sigma model with light quarks

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    We investigate the role of undetermined finite contributions generated by radiative corrections in a SU(2)×SU(2)SU(2)\times SU(2) linear sigma model with quarks. Although some of such terms can be absorbed in the renormalization procedure, one such contribution is left in the expression for the pion decay constant. This arbitrariness is eliminated by chiral symmetry.Comment: 9 pages. Added references through the text; an author was added due to an important contribution; corrected typos; the title also was changed. Submitted to Modern Physics Letter

    Sonoluminescing air bubbles rectify argon

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    The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the percentage of inert gas within the bubble. We propose a theory for this dependence, based on a combination of principles from sonochemistry and hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent reaction to water soluble gases implies that strongly forced air bubbles eventually consist of pure argon. Thus it is the partial argon (or any other inert gas) pressure which is relevant for stability. The theory provides quantitative explanations for many aspects of SBSL.Comment: 4 page

    Infusing Environmental Sustainability into Textile and Apparel Curriculum: Professional Development Needs for a Discipline in Transition

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    In recent years there is evidence that apparel industry firms are beginning to acknowledge the environmental impacts of their products and processes. For example, the Sustainable Apparel Coalition (SAC) was founded by a group of apparel industry, trade, governmental, and non-profit organizations as a collaborative initiative to reduce the environmental consequences of the soft goods industry (i.e., water use and quality; energy and emissions; waste; chemicals and toxicity) as well as social and labor issues (www.apparelcoalition.org/desired-outcomes). As these and other industry leaders invest in and support change toward greater sustainability, the educational programs that prepare young textile and apparel (TA) professionals must evolve as well. Incorporating environmental sustainability competencies and learning outcomes into textile and apparel curriculum is becoming an imperative

    Mechanisms for Stable Sonoluminescence

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    A gas bubble trapped in water by an oscillating acoustic field is expected to either shrink or grow on a diffusive timescale, depending on the forcing strength and the bubble size. At high ambient gas concentration this has long been observed in experiments. However, recent sonoluminescence experiments show that in certain circumstances when the ambient gas concentration is low the bubble can be stable for days. This paper presents mechanisms leading to stability which predict parameter dependences in agreement with the sonoluminescence experiments.Comment: 4 pages, 3 figures on request (2 as .ps files
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