284 research outputs found

    The sigma-Meson Production in Excited Upsilon Decay Processes

    Full text link
    We analyze the pipi production amplitudes in the excited Upsilon decay processes, Upsilon (2S) to Upsilon (1S)pi^+pi^-, Upsilon (3S) to Upsilon (1S)pi^+pi^- and Upsilon (3S) to Upsilon (2S)pi^+pi^-, and the pipi and KKbar production amplitudes in the charmonium decay processes, psi (2S) to Jpsi pi^+pi^- and Jpsi to phi pi^+pi^-, phi K^+K^-, including the possible effect of light sigma production. The amplitudes are parametrized by the sum of Breit-Wigner amplitudes for the sigma and the other relevant particles and of the direct 2pi-production amplitude, following the VMW method. All the pipi (and KKbar mass spectra are reproduced well with the obtained values of sigma-parameters, m_sigma =526(+48,-37)MeV and Gamma_sigma =301(+145,-100)MeV, which is almost consistent with the values in our previous phase shift analyses.Comment: proc. of "Hadron '01," Protvino, Russia, Aug, 2001. 5 pages, uses ptptex.st

    Light sigma-Meson Production in Excited Upsilon Decay Processes I: Analyses

    Full text link
    We analyze the pi pi production amplitudes in the excited Upsilon decay processes, Upsilon(2S)-->Upsilon(1S)pi+pi-, Upsilon(3S)-->Upsilon(1S)pi+pi- and Upsilon(3S)-->Upsilon(2S)pi+pi-, and the pi pi and KKbar production amplitudes in the charmonium decay processes, psi(2S)-->J psi pi+pi- and J psi-->phi pi+pi-, phi K+K-. The amplitudes are parametrized by the sum of Breit-Wigner amplitudes for the sigma and the other relevant particles and of the direct 2pi-production amplitude, following the VMW method. All the pi pi (and KKbar) invariant mass spectra are reproduced well with the sigma Breit-Wigner amplitude by using the common parameters, m_sigma=526^(+48)_(-37) MeV and Gamma_sigma =301^(+145)_(-100) MeV, which is almost consistent with the values obtained in our previous phase shift analyses. This strongly suggests the existence of light sigma-meson.Comment: proc. of ``Possible Existence of sigma-Meson and Its Implication to Hadron Physics," YITP, Kyoto, June 12--14, 2000. 5 pages, uses ptptex.st

    The Ds(2317) and Ds(2463) Mesons as Scalar and Axial-Vector Chiralons in the Covariant Level-Classification Scheme

    Full text link
    The new narrow mesons observed recently in the final states Ds+ pi0 and Ds*+ pi0 are pointed out to be naturally assigned as the ground-state scalar and axial-vector chiralons in the c sbar system, which would newly appear in the covariant hadron-classification scheme proposed a few years ago.Comment: 8 pages, 1 figure, uses ptptex.st

    Effect of light sigma-meson Production in ppbar --> 3 pi0 at rest

    Full text link
    The pi0 pi0 mass spectra and angular distributions around KKbar -threshold and at 1.5 GeV in ppbar (at rest) --> 3 pi0 in the Crystal Barrel experiment are reanalyzed by applying the new method, which is consistent with unitarity of S-matrix and expressed directly by resonance parameters. The effects of light sigma-meson production are clearly seen to improve the fit with sigma, in comparing with the fit without sigma.Comment: 8 pages, 1 Postscript figure, uses ptptex.st

    Production of 3π03\pi^{0} and η2π0\eta2\pi^{0} from π−p\pi^{-}p collision in GAMS experiment

    Get PDF
    The data on the pi- p --> M0 n, with M0 = pi0 pi0 pi0 or pi0 pi0 eta obtained in the GAMS experiment may be useful to study the sigma(400--700) and a_1^chi (1000), which can be taken as chiral partners of pi and rho, respectively. A preliminary analysis for 3pi0 invariant mass spectra gives a support for the assumed a_1^chi with a mass of 930 MeV and Gamma = 170 MeV

    ReAlignerV: Web-based genomic alignment tool with high specificity and robustness estimated by species-specific insertion sequences

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Detecting conserved noncoding sequences (CNSs) across species highlights the functional elements. Alignment procedures combined with computational prediction of transcription factor binding sites (TFBSs) can narrow down key regulatory elements. Repeat masking processes are often performed before alignment to mask insertion sequences such as transposable elements (TEs). However, recently such TEs have been reported to influence the gene regulatory network evolution. Therefore, an alignment approach that is robust to TE insertions is meaningful for finding novel conserved TFBSs in TEs.</p> <p>Results</p> <p>We constructed a web server 'ReAlignerV' for complex alignment of genomic sequences. ReAlignerV returns ladder-like schematic alignments that integrate predicted TFBSs and the location of TEs. It also provides pair-wise alignments in which the predicted TFBS sites and their names are shown alongside each sequence. Furthermore, we evaluated false positive aligned sites by focusing on the species-specific TEs (SSTEs), and found that ReAlignerV has a higher specificity and robustness to insertions for sequences having more than 20% TE content, compared to LAGAN, AVID, MAVID and BLASTZ.</p> <p>Conclusion</p> <p>ReAlignerV can be applied successfully to TE-insertion-rich sequences without prior repeat masking, and this increases the chances of finding regulatory sequences hidden in TEs, which are important sources of the regulatory network evolution. ReAlignerV can be accessed through and downloaded from <url>http://genet.med.kagawa-u.ac.jp/</url>.</p

    The distribution and number of Leu-7 (CD57) positive cells in lung tissue from patients with pulmonary fibrosis.

    Get PDF
    Leu-7 positive lymphocytes, including natural killer cells, play an important role in the immune system's surveillance function to prevent the development of cancer. The incidence of lung cancer is significantly high in patients with end-stage pulmonary fibrosis. We hypothesized that the number of Leu-7 positive cells may be decreased in areas of severe pulmonary fibrosis. To demonstrate this, Leu-7 positive cells were immunohistochemically stained in 41 lung specimens obtained from patients with idiopathic pulmonary fibrosis and pulmonary fibrosis associated with collagen vascular disorders. The number of Leu-7 positive cells was evaluated according to the pathological findings. In pathologically normal lung, Leu-7 positive cells were mostly found within the capillaries of the septa and rarely in the alveolar space or the stroma. The number of Leu-7 positive cells was 0.69 +/- 0.15 in areas of advanced fibrosis (n = 41), 2.39 +/- 0.60 in areas that had newly developeing fibrosis (n = 41), 1.14 +/- 0.57 in bronchiolitis obliterans organizing pneumonia (n = 9), and 1.35 +/- 0.87 in diffuse alveolar damage (DAD) (n = 11). The number of Leu-7 positive cells in areas of newly developing fibrosis (2.39 +/- 0.60) was significantly higher than that in areas of established fibrosis (0.69 +/- 0.15, P &#60; 0.05). Our present study demonstrates a significant decrease in the number of Leu-7 positive cells in areas of advanced fibrosis. This evidence may partly explain the high incidence of lung cancer associated with pulmonary fibrosis.</p
    • …
    corecore