نتایج جستجو برای: gev
تعداد نتایج: 18737 فیلتر نتایج به سال:
We estimate the heavy quark effective theory parameter λ1 from inclusive semileptonic B-meson decay spectrum. By using recent CLEO double lepton tagging data of B → Xeν, which shows the lepton momentum as low as 0.6 GeV, we extracted λ1 ∼ −0.58 GeV. We also derived Λ ∼ 0.46 GeV and |Vcb| = 0.041 ± 0.002. [email protected] [email protected], http://phya.yonsei.ac.kr/ ̃cskim/
تغییرات انرژی حالت پایه مزون چارمونیم براساس معادله شرودینگر غیرنسبیتی و با استفاده از پتانسیلهای کرنل ، لگاریتمی ،کلی و مارتین با کمک تئوری اختلال و روش وردشی در فضای ناجابجاگر بدست آمده است. نشان داده شده که در اولین مرتبهاختلال، تغییرات انرژی حالت پایه مزون چارمونیم در فضای ناجابجاگر با توان دوم پارامتر این فضا متناسب است. حد بالای1/023 تخمین زده شده است. این مقادیر برای پارامتر فضای gev 0/1...
در بسیاری از مدلها, مزونها از جفت کوارک و ضو کوارک که در یک پتانسیل نگهدارنده حرکت می کنند تشکیل شده اند. در این مدل اثر پتانسیلهای برهم کنش اضافی مربوط به اسپین و ایزواسپین ذرات کوارک وجود دارد. در مدل کوارکهای تشکیل دهنده کایرال برهم کنش پتانسیلهای فوق ریز به وسیله بوزونهای گلدستون به علت وابستگی اسپین و ایزواسپین در توصیف طیف انرژیهای کمتر از1/7 gev در نظر گرفته شده است. در این مدل نه تنها...
The mass of the top quark Mtop is interesting both as a fundamental parameter of the standard model and as an important input to precision electroweak tests. The Collider Detector at Fermilab (CDF) has a robust program of top quark mass analyses, including the most precise single measurement, Mtop = 173.4 ± 2.8 GeV/c 2 , using 680 pb −1 of p¯ p collision data. A combination of current results f...
We have measured the branching fraction and photon energy spectrum for the radiative penguin process b → sγ. We find B(b → sγ) = (3.21 ± 0.43 ± 0.27 −0.10) × 10 , where the errors are statistical, systematic, and from theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, 〈Eγ〉 = 2.346± 0.032± 0.011 GeV, and 〈E γ〉−〈Eγ〉 2 = 0.0226±0.0066±0.0020 GeV, wh...
The Generalized Extreme Value (GEV) distribution is used to model the electric field inside a Reverberation Chamber (RC). GEV distribution is particularly indicated for this application where the maximums of the field are studied, as it specifies the theoretical distribution of the maximums according to the Fisher-Tippett theorem. In a first part of this paper we present the Fisher-Tippett theo...
In this work the charm and bottom quark masses are determined from QCD moment sum rules for the charmonium and upsilon systems. In our analysis we include both the results from non-relativistic QCD and perturbation theory at next-next-to-leading order. For the pole masses we obtain Mc = 1.75± 0.15 GeV and Mb = 4.98± 0.125 GeV. Using the potential-subtracted mass in intermediate steps of the cal...
A personal view of current prospectives in particle physics is presented, inspired by the contributions to this meeting. Particular emphasis is laid in precision tests of the Standard Model and the search for the Higgs boson, on probes of CP violation, on speculations about possible physics beyond the Standard Model, on neutrino masses and oscillations, on the quest for supersymmetry, on opport...
I review what lattice QCD simulations have to tell us about the glueball spectrum. We see that the various lattice calculations are in good agreement with each other. They predict that prior to mixing with nearby flavour singlet quarkonia the lightest glueball states are the scalar at 1.61 ± 0.15 GeV, the tensor at 2.26 ± 0.22 GeV, and the pseudoscalar at 2.19 ± 0.32 GeV.
We present PHENIX recent results on charged particle and transverse energy densities measured at mid-rapidity in Au-Au collisions at √ s NN =130 GeV and 200 GeV over broad range of centralities. The mean transverse energy per charged particle is derived. The first PHENIX measurements at √ s NN =19.6 GeV are also presented. A comparison with calculations from various theoretical models is perfor...
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