نتایج جستجو برای: روش charm
تعداد نتایج: 374417 فیلتر نتایج به سال:
During the last few years, the main emphasis in the study of heavy particle production (i.e. e+emainly charm) by other means than annihilation has been on the production mechanisms. Because of the relative cleanliness of the charm signal in the e+eprocess, most of the data on the properties of the charm particles has originated from that source. There are already indications, however, that this...
در مدل استاندارد ذرات بنیادی به دلیل مکانیزم gim بر هم کنش های جریان خنثی به دلیل تغییر طعم (fcnc) کوارک تاپ در سطح درختی وجود ندارند و فقط در حلقه ها دیده می شوند . بنابر این مشاهده هر فرآیند fcnc کوارک تاپ یک شاهد برای وجود مدلی ماورائ مدل اساندارد ذرات بنیادی است . مدل هایی مانند mssm , technicolor ماورائ مدل استاندارد ذرات بنیادی وجود دارند که در آنها نیز پدیده fcnc در سطح نمودارهای درختی و...
مدلهای اقتصاد چندمنطقهای که مجموعهای از اقتصادهای منطقهای را به صورت پیوسته به هم ارائه داده و اثرات متقابل بین مناطق را نشان میدهند، نیازمند محاسبه صادرات هر منطقه به سایر مناطق و واردات هر منطقه از سایر مناطق هستند. در فرآیند بررسی روابط بینمنطقهای و اثرات متقابل و ایجاد جدول داده-ستانده چندمنطقهای، حلقه مفقوده برآورد تجارت بینمنطقهای است. در این مطالعه با هدف برآورد تجارت بینمنطقه...
Leading charm hadrons produced in hadron-nucleus interactions cannot be adequately described within the parton fusion model. Recent results on charm baryon production in Σ − A interactions at 330 GeV with the WA89 detector disagree with fusion predictions. Intrinsic heavy quark pairs in the Σ − (dds) wavefunction provide a simple mechanism for producing fast charm hadrons. We calculate leading ...
Charm hadrons were produced copiously in ep collisions with a centre-of-mass energy of 318GeV at HERA providing a means to study charm hadronisation. During first phase of the HERA operation (1992-2000), the ZEUS collaboration accumulated data sample corresponding to an integrated luminosity of ∼ 120 pb. Measurements of the D, D, D and Λc production a with the HERA I data were used to determine...
— This is part I of a two-part review of charm physics. After briefly recapitulating the history of the charm quantum number we sketch the experimental environments and instruments employed to study the behaviour of charm hadrons and then describe the theoretical tools for treating charm dynamics. After discussing a wide range of inclusive production processes we analyze the spectroscopy of had...
The Charm++ parallel programming system provides a modular performance interface that can be used to extend its performance measurement and analysis capabilities. The interface exposes execution events of interest representing Charm++ scheduling operations, application methods/routines, and communication events for observation by alternative performance modules configured to implement different...
This is a historical review of the discovery of naked charm particles and lifetime differences among charm species. These discoveries in the field of cosmic-ray physics were made by the innovation of nuclear emulsion techniques in Japan. A pair of naked charm particles was discovered in 1971 in a cosmic-ray interaction, three years prior to the discovery of the hidden charm particle, J/Psi, in ...
We present theoretical and experimental considerations pertaining to deeply inelastic heavyflavour production at HERA. The various theoretical uncertainties in the cross section calculation are discussed. Cuts are imposed to determine the fraction of charm production accessible to the detectors. The production of charm at asymptotic Q and bottom production are also covered. Experimental aspects...
An effective hadronic Lagrangian including the charm mesons is introduced to study their interactions in hadronic matter. Using coupling constants that are determined either empirically or by the SU(4) symmetry, we have evaluated the absorption cross sections of J/ψ and the scattering cross sections of D and D∗ by π and ρ mesons.
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