نتایج جستجو برای: charm bond

تعداد نتایج: 75189  

2013
Thomas Lang Hendrik van Hees Jan Steinheimer Marcus Bleicher

The Compressed Baryonic Matter (CBM) experiment at the Facility for Anti-proton and Ion Research (FAIR) will provide new possibilities for charm-quark (D-meson) observables in heavy-ion collisions at low collision energies and high baryon densities. To predict the collective flow and nuclear modification factors of charm quarks in this environment, we apply a Langevin approach for the transport...

2008
I. I. Bigi

Second-generation theoretical technologies – heavy quark expansions, QCD sum rules and QCD simulations on the lattice – are arriving on the scene, allowing a treatment of charm decays that is genuinely based on QCD. The availability of those theoretical tools strengthens the case for the need for comprehensive precision measurements of charm decays. It is pointed out that the decays of charm me...

2004
H. Wittig

We present a strategy designed to separate several possible origins of the well-known enhancement of the ∆I = 1/2 amplitude in non-leptonic kaon decays. In particular, we seek to disentangle the contribution of physics at the typical QCD scale (soft-gluon exchange) from the effects at the scale of the charm quark mass. This is achieved by considering QCD with an unphysically light charm quark, ...

1999
Ziwei Lin Bin Zhang

The scattering cross sections of charm mesons with hadrons such as the pion, rho meson, and nucleon are studied in an effective Lagrangian. In heavy ion collisions, rescattering of produced charm mesons by hadrons affects the invariant mass spectra of both charm meson pairs and dileptons resulting from their decays. These effects are estimated for heavy ion collisions at Super Proton Synchrotro...

2003
Leonid Gladilin

The measured D, D, D, D s and Λ c photoproduction cross sections have been used to determine charm fragmentation ratios and fractions of c quarks hadronising as a particular charm hadron, f(c → D,Λc). Events with a D meson produced in association with an energetic jet have been used to measure the charm fragmentation function. The results are compared with different models and with previous mea...

1997
V. Emel’yanov A. Khodinov S. R. Klein R. Vogt

The effect of gluon shadowing on charm quark production in large impact parameter ultrarelativistic heavy ion collisions is investigated. Charm production cross sections are calculated for a range of non-central impact parameters which can be accurately inferred from the global transverse energy distribution. We show that charm production is a good probe of the local parton density which determ...

2008
R. Vogt

We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that due to the small charm quark mass, which amplifies the effect of varying the other parameters in the calculation, the uncertainty on the total charm cross section is difficult to

2008
Dan Abramovich

We prove that Conjecture H of Caporaso et al. [CHarM], §6 together with Lang’s conjecture implies the uniformity of rational points on varieties of general type, as predicted in [CHarM]; a few applications in arithmetic and geometry are stated. As in [א], one uses the fact that rational points on X B are n-tuples of points when trying to bound n, as well as the fact that the Noetherian inductio...

ژورنال: :پژوهش ها و سیاست های اقتصادی 0
مسعود همایونی فر مهدی خداپرست مشهدی محمد رضا لطفعلی پور فرهاد ترحمی

تهیه جداول داده- ستانده منطقه ای با روش آماری، پیچیده و زمانبر است. بنابراین، پژوهشگران از  روش های غیرآماری استفاده می کنند. جدیدترین مدل تهیه جدول داده- ستانده منطقه­ای  aflqنام دارد. ولی با توجه به آمار حساب­های منطقه­ای مرکز آمار ایران، در این روش، صادرات و تقاضای نهایی به صورت پسماند در نظر گرفته می­شوند. ضمن اینکه صادرات مجدد بین مناطق نادیده گرفته می­شود. برای غلبه بر مشکلات فوق، در این ...

2001
SANJAY PADHI

The study of heavy-flavoured jets allows a detailed investigation of pQCD and the potential to understand the heavy quark production mechanism. In this paper only charm is considered. Measurements relating to the universality of charm fragmentation fraction are made. Measurements of both inclusive jets and dijets with a charm meson have been performed to probe the dynamics and the contents of t...

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