183 research outputs found

    Prospects for Pentaquark Searches in e+e−e^+e^- Annihilations and γγ\gamma\gamma Collisions

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    Recent strong experimental evidence of a narrow exotic S = +1 baryon resonance, Θ+\Theta^+, suggests the existence of other exotic baryons. We discuss the prospects of confirming earlier experimental evidence of Θ+\Theta^+ and the observation of additional hypothetical exotic baryons in e+e−e^+e^- annihilations and γγ\gamma\gamma collisions at LEP and B Factories

    History of exotic Meson (4-quark) and Baryon (5-quark) States

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    I briefly review the history of exotic meson (4-quark) and baryon (5-quark) states, which is rooted in the formalism of Regge pole and duality. There are robust model-independent predictions for the exchange of 4-quark (Baryonium) Regge trajectories in several processes, which are strongly supported by experiment. On the other hand the predictions for the spectroscopy of 4-quark resonances are based on specific QCD inspired models, with some experimental support. The corresponding predictions for the recently discovered exotic baryon (Pentaquark) state are briefly discussed.Comment: 14 pages Latex including 4 eps figures, final version to appear as a topical review in J. Phys.

    Increased frequency and nocturia in a middle aged male may not always be due to Benign Prostatic Hypertrophy (BPH): a case report

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    Primary signet ring cell carcinoma of urinary bladder is a rare type of bladder tumor and carries a very high mortality rate. It may have a clinical presentation similar to common diseases like Benign Prostatic Hypertrophy (BPH) and the management options are extremely limited. We report a case of 58 year old Caucasian male who presented with a 5 month history of increased frequency of urination, nocturia and weight loss without any fever or hematuria. He was found to have an increased creatinine of 2.8 mg/dl and a prostate specific antigen level of 0.18 ng/ml. His azotemia was thought to be secondary to BPH. A foley catheter was initially placed with a plan for outpatient follow up. On removal of the catheter his problems persisted and he returned to the hospital. Diagnostic work up including abdominal ultrasonography, computed tomography (CT) scan, retrograde pyelogram, cystography and cystoscopic biopsies revealed the diagnosis of primary signet ring cell carcinoma of urinary bladder. Although cystectomy was planned, our patient passed away before this could be done

    Deathly Drool: Evolutionary and Ecological Basis of Septic Bacteria in Komodo Dragon Mouths

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    Komodo dragons, the world's largest lizard, dispatch their large ungulate prey by biting and tearing flesh. If a prey escapes, oral bacteria inoculated into the wound reputedly induce a sepsis that augments later prey capture by the same or other lizards. However, the ecological and evolutionary basis of sepsis in Komodo prey acquisition is controversial. Two models have been proposed. The “bacteria as venom” model postulates that the oral flora directly benefits the lizard in prey capture irrespective of any benefit to the bacteria. The “passive acquisition” model is that the oral flora of lizards reflects the bacteria found in carrion and sick prey, with no relevance to the ability to induce sepsis in subsequent prey. A third model is proposed and analyzed here, the “lizard-lizard epidemic” model. In this model, bacteria are spread indirectly from one lizard mouth to another. Prey escaping an initial attack act as vectors in infecting new lizards. This model requires specific life history characteristics and ways to refute the model based on these characteristics are proposed and tested. Dragon life histories (some details of which are reported here) prove remarkably consistent with the model, especially that multiple, unrelated lizards feed communally on large carcasses and that escaping, wounded prey are ultimately fed on by other lizards. The identities and evolutionary histories of bacteria in the oral flora may yield the most useful additional insights for further testing the epidemic model and can now be obtained with new technologies

    Moments of inertia, nucleon axial-vector coupling, the {\bf 8}, {\bf 10}, 10ˉ\bar{\bf 10} and 273/2{\bf 27}_{3/2} mass spectrums and the higher SU(3)_f representation mass splittings in the Skyrme model

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    The broad importance of a recent experimental discovery of pentaquarks requires more theoretical insight into the structure of higher representation multiplets. The nucleon axial-vector coupling, moments of inertia, the {\bf 8}, {\bf 10}, 10ˉ\bar{\bf 10}, and 273/2{\bf 27}_{3/2} absolute mass spectra and the higher SU(3)f_f representation mass splittings for the multiplets 8{\bf 8}, 10{\bf 10}, 10ˉ\bar{\bf 10}, 27{\bf 27}, 35{\bf 35}, 35ˉ\bar{\bf 35}, and 64\bf 64 are computed in the framework of the minimal SU(3)f{\rm SU(3)_f} extended Skyrme model by using only one free parameter, i.e., the Skyrme charge ee. The analysis presented in this paper represents simple and clear theoretical estimates, obtained without using any experimental results for higher (10ˉ\bar{\bf 10},...) multiplets. The obtained results are in good agreement with other chiral soliton model approaches that more extensively use experimental results as inputs.Comment: 22 pages, 12 figures, 9 tables, version accepted in JHE

    Antikaon angular distributions in the reaction γd→K−Θ+p→K−K+np{\gamma}d \to K^-{\Theta}^+p \to K^-K^+np near the threshold and the parity of the Θ+{\Theta}^+ pentaquark

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    Within spectator model we study the reaction Îłd→K−Θ+p→K−K+np{\gamma}d \to K^-{\Theta}^+p \to K^-K^+np in the threshold energy region. We present the predictions for the exclusive and inclusive antikaon angular distributions in the laboratory system for this reaction calculated for two possible parity states of the Θ+{\Theta}^+ resonance at 1.5 and 1.75 GeV beam energies with and without imposing the relevant kinematical cuts on those parts of the sampled phase space where contribution from the main background sources associated with the ϕ(1020){\phi}(1020), Λ(1520){\Lambda}(1520) production as well as with the K−pK^-p--rescattering in the final state, is expected to be dominant. We show that under chosen kinematics these distributions are sensitive to the Θ+{\Theta}^+ parity and, therefore, can be used as a filter for the determination of its parity.Comment: 18 pages, 8 figures; will be published in Phys.Atom.Nucl_4_200

    Mumps of the Heart

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