相关论文: Heavy Hybrids from NRQCD
We use lattice methods to evaluate from first principles the spectrum of hybrid mesons produced by gluonic excitations in quenched QCD with quark masses near the strange quark mass. For the spin-exotic mesons with $J^{PC}=1^{-+},\ 0^{+-}$,…
A report on the recent next-to-leading order QCD calculations to ttbb and ttjj at the CERN Large Hardon Collider is given. The elements of the calculation are briefly summarized and results for integrated and differential cross sections are…
We show that when the factorized cross section for heavy quarkonium production includes next-to-leading power (NLP) contributions associated with the production of the heavy quark pair at short distances, it naturally reproduces all high…
We simulate quenched QCD with the overlap Dirac operator. We work with the Wilson gauge action at beta=6 on an 18^3x64 lattice. We calculate quark propagators for a single source point and quark mass ranging from am_q=0.03 to 0.75. We…
I present an introduction to the NRQCD factorization method for calculating annihilation rates and inclusive production rates for heavy quarkonium. Using this method, annihilation decay rates and sufficiently inclusive cross sections are…
We predict exotic doubly heavy--strange pentaquarks with minimal quark content $u\bar d sQQ'$ ($QQ'=cc,bc,bb$) within a coupled-channel unitary framework where the interaction is derived from an extension of the local hidden gauge approach…
We review recent model independent determinations of the radiative transitions of heavy quarkonium obtained using potential NRQCD.
Uncertainties in the next-to-leading-order calculations of heavy-quark ($Q$) production are investigated. Predictions for total cross sections, single-inclusive distributions of heavy quarks and heavy flavoured hadrons, as well as for…
The spectrum of the $0^{++}$, $0^{--}$, $1^{-+}$ and $1^{+-}$ heavy-light hybrids have been calculated in HQET. The interpolated current of the hybrid is chosen as $g\bar q\gamma_{\alpha}G_{\alpha\mu}^aT^ah_{\it v}(x)$, $g\bar…
An introduction to the recent developments in perturbative heavy quarkonium physics is given. Covered are the effective theories NRQCD, pNRQCD and vNRQCD, the threshold expansion, the role of renormalons, and applications to bottom and top…
I review the NRQCD factorization approach for quarkonium production and compare its predictions with measurements in hadron-hadron and ep collisions.
The multiple hadron production in the events induced by the heavy primary quarks in $e^+e^-$ annihilation is reconsidered with account of corrected experimental data. New value for the multiplicity in $b\bar{b}$ events is presented on the…
During the last year, analytic expressions for the two-loop QCD corrections to the form factors for the vector, axial-vector, scalar and pseudo-scalar vertices involving a pair of heavy quarks, $Q \bar{Q}$, were calculated. The results are…
We present the calculation of QCD radiative corrections to heavy-quark production at NNLO. The calculation is implemented in an updated version of \textsc{Matrix}, which allows us to obtain multidifferential predictions for stable top…
Processes of heavy quark production at HERA, TEVATRON and THERA energies are considered using the semihard ($k_T$ factorization) QCD approach with emphasis on the BFKL dynamics of gluon distributions.
The combined large N_c and heavy quark limit for baryons containing a single heavy quark is discussed. The combined large N_c and heavy quark expansion of the heavy quark bilinear operators is obtained. In the combined expansion the…
Recent findings on the spectrum of heavy-quark mesons from computer simulations of quarks and gluons in lattice QCD are summarized, with particular attention to quark-antiquark states bound by an excited gluon field. The validity of a…
We describe the WA89 Collaboration experimental data on Lambda, Sigma(-), Sigma(+), Xi(-), and Omega(-) baryons, and bar(Lambda) and bar(Xi(+)) antibaryons production in Sigma(-) collisions with C and Cu targets at 345 GeV/c (sqrt(s_(Sigma…
We speculate about a heavy bottom-charm six-quark baryon. A semiclassical and a gaussian estimate reveal that the octet-octet bbb-ccc configuration can be energetically favored with respect to the singlet-singlet one. This result suggests…
In this talk I summarize a part of the work done in a recent collaboration with C. Burgess, J. Cline, D. London and E. Nardi \cite{b96}. We analyze the observed discrepancy between $R_b(\equiv\gb /\ghad )$ as measured at LEP and its…