3,014 research outputs found

    Ultraviolet and Infrared Divergences in Implicit Regularization: a Consistent Approach

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    Implicit Regularization is a 4-dimensional regularization initially conceived to treat ultraviolet divergences. It has been successfully tested in several instances in the literature, more specifically in those where Dimensional Regularization does not apply. In the present contribution we extend the method to handle infrared divergences as well. We show that the essential steps which rendered Implicit Regularization adequate in the case of ultraviolet divergences have their counterpart for infrared ones. Moreover we show that a new scale appears, typically an infrared scale which is completely independent of the ultraviolet one. Examples are given.Comment: 9 pages, version to appear in Mod. Phys. Lett.

    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

    Basketball game-related statistics that discriminate between teams season-long success

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    The aim of the present study was to identify the game-related statistics that discriminate between season-long successful and unsuccessful basketball teams participating in the Spanish Basketball League (LEB1). The sample included all 145 average records per season from the 870 games played between the 2000-2001 and the 2005-2006 regular seasons. The following game-related statistics were gathered from the official box scores of the Spanish Basketball Federation: 2- and 3-point field-goal attempts (both successful and unsuccessful), free-throws (both successful and unsuccessful), defensive and offensive rebounds, assists, steals, turnovers, blocks (both made and received), and fouls (both committed and received). To control for season variability, all results were normalized to minutes played each season and then converted to z-scores. The results allowed discrimination between best and worst teams' performances through the following game-related statistics: assists (SC=0.47), steals (SC=0.34), and blocks (SC=0.30). The function obtained correctly classified 82.4% of the cases. In conclusion, season-long performance may be supported by players' and teams' passing skills and defensive preparation

    Synthesis of 1-amino-4-(2´-thienyl)phthalazine derivatives

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    A synthesis of 1-amino substituted 4-(2´-thienyl)-phthalazines is described from halo- derivatives of 4-(2´-thienyl)-1-(2H)-phthalazinone 3.Fundação para a Ciência e Tecnologia. FEDER - POCTI (ref. POCTI/QUI/37816/2001)

    Synthesis of arylamino-thieno-oxobutanamides and reactivity studies on the cyclisation with the Lawesson´s reagent

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    1-aryl-2-thienyl-substituted pyrroles and 5-arylamino-2,2´-bithiophenes are synthesized by treatment of arylamino-thieno-oxobutanamides with Lawesson´s reagent. These in turn are prepared by direct amidation of 4-oxo-(2-thienyl)butanoic acid through DCC/BtOH mediated reaction.Fundação para a Ciência e Tecnologia. FEDER - POCTI/QUI/37816/2001

    Arylamino-thieno-oxobutanamides under Lawesson’s conditions : competition between thienylpyrrole and bithiophene formation

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    1-Aryl-2-thienyl-substituted pyrroles and/or 5-arylamino-2,2´-bithiophenes were synthesized by treatment of arylaminothieno-oxobutanamides with Lawesson’s reagent. These in turn were prepared by direct amidation of 4-oxo-(2-thienyl)butanoic acid through DCC–BtOH mediated reactions.Fundação para a Ciência e Tecnologia (FCT

    Effects of Inelastic Neutrino-Nucleus Scattering on Supernova Dynamics and Radiated Neutrino Spectra

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    Based on the shell model for Gamow-Teller and the Random Phase Approximation for forbidden transitions, we have calculated reaction rates for inelastic neutrino-nucleus scattering (INNS) under supernova (SN) conditions, assuming a matter composition given by Nuclear Statistical Equilibrium. The rates have been incorporated into state-of-the-art stellar core-collapse simulations with detailed energy-dependent neutrino transport. While no significant effect on the SN dynamics is observed, INNS increases the neutrino opacities noticeably and strongly reduces the high-energy tail of the neutrino spectrum emitted in the neutrino burst at shock breakout. Relatedly the expected event rates for the observation of such neutrinos by earthbound detectors are reduced by up to about 60%.Comment: 4 pages, 2 figures, 1 tabl
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