نتایج جستجو برای: charm bond

تعداد نتایج: 75189  

1999
F. M. Steffens

A next-to-leading order analysis of inelastic electroproduction of charm is performed using an interpolating scheme which maps smoothly onto massless QCD evolution at large Q2 and photon–gluon fusion at small Q2. In contrast with earlier analyses, this scheme allows the inclusion of quark and target mass effects and heavy quark thresholds, as well as possible non-perturbative, or intrinsic, cha...

2007
T. Aso H. Miyata T. Sasaki K. Ohkubo M. Oyoshi M. Sato N. Takashimizu M. H. Lee F. Liu A. Maki T. Omori S. Terada P. Kirk T. J. Wang A. Abashian K. Gotow L. Piilonen S. K. Choi C. Rosenfeld S. Behari S. Kobayashi A. Murakami M. Yang A. Bodek B. J. Kim J. S. Kang H. S. Ahn

Measurements of open charm production in photon-photon collisions made with the AMY detector at TRISTAN are reported. Charmed hadrons were identi ed by detecting the high momentum muons or electrons from their semileptonic decays. The data sample corresponds to an integrated luminosity of 275 pb 1 at an average center of mass energy of 58 GeV. Results are presented in the form of cross sections...

2000
P. Braun-Munzinger J. Stachel

To investigate a recent proposal that J/ψ production in ultra-relativistic nuclear collisions is of thermal origin we have reanalyzed the data from the NA38/50 collaboration within a thermal model including charm. Comparison of the calculated with measured yields demonstrates the non-thermal origin of hidden charm production at SPS energy. However, the ratio ψ ′ /(J/ψ) exhibits, in central nucl...

2004
Svjetlana Fajfer Jernej Kamenik

Motivated by recent experimental results we reconsider semileptonic D → P ℓν ℓ decays within a model which combines heavy quark symmetry and properties of the chiral Lagrangian. We include all observed charm meson resonances in our Lagrangian and determine their impact on the charm meson semileptonic form factor F+. We find that the inclusion of recently discovered charm resonances in the model...

1997
PAUL E. KARCHIN

Recent results on the hadroproduction of charm and beauty are discussed in the context of the current theoretical and experimental status. The areas covered include production of open charm and beauty particles and charm and beauty quarkonia. Experimental results from both fixed target and colliding beam experiments are presented and compared to theoretical predictions. Predictions based on QCD...

2002
G. De Lellis F. Di Capua P. Migliozzi

The way a charm-quark fragments into a charmed hadron is a challenging problem both for the theoretical and the experimental particle physics. Moreover, in neutrino induced charmproduction, peculiar processes occur such as quasi-elastic and diffractive charm-production which make the results from other experiments not directly comparable. We present here a method to extract the charmed fraction...

2008
I. I. Bigi

The recently obtained strong evidence for D − D̄ oscillations from the B factories provides an important benchmark in our search for New Physics in charm transitions. While the theoretical verdict on the observed values of xD and yD is ambiguous – they could be fully generated by SM dynamics, yet could contain also a sizable contribution from New Physics – such oscillations provide a new stage f...

2004
Dénes Molnár

From covariant transport theory, a significant ∼ 10% light quark elliptic flow at RHIC implies an elliptic flow of similar magnitude for charm quarks, at moderately large pT > 2.5 − 3 GeV. At lower transverse momenta, charm quark elliptic flow reduces progressively, reminiscent of the mass ordering pattern in ideal hydrodynamics. From the quark flows we predict the elliptic flow of D mesons at ...

2004
Svjetlana Fajfer Jernej Kamenik

Motivated by recent experimental results we reconsider semileptonic D → P ℓν ℓ decays within a model which combines heavy quark symmetry and properties of the chiral Lagrangian. We include all observed charm meson resonances in our Lagrangian and determine their impact on the charm meson semileptonic form factors. We find that the inclusion of recently discovered charm resonances in the model l...

2006
Chao-Hsi Chang Jian-Ping Ma Cong-Feng Qiao Xing-Gang Wu

We study effects of the intrinsic charm on the hadronic production of Ξcc at SELEX, Tevatron and LHC. By taking the intrinsic charm into account, the cross-section of the production at SELEX is changed significantly. In contrast, at LHC and Tevatron the change is small because the gluon-gluon fusion becomes dominant. The measured cross-section at SELEX is much larger than the prediction based o...

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