Related papers: Perturbatively stable observables in heavy-quark l…
In the framework of perturbative QCD in the fourth order over the $\alpha_s$ coupling constant for the production of two pairs of quarks and in the model of weak binding of the quarks into meson, the analysis of the hadronic production of…
Drell-Yan lepton pairs with finite transverse momentum are produced when the vector boson recoils against (multiple) parton emission(s), and is determined by QCD dynamics. At small transverse momentum, the fixed order predictions break down…
We calculate the Lamb, fine and hyperfine shifts in $b\bar b$ with $n=2$, $l=0,1$. Radiative corrections as well as leading nonperturbative corrections (known to be due to the gluon condensate) are taken into account. The calculation is…
We study relativistic corrections to prompt psi(2S) at high pT in hadron colliders. Our calculation employs leading-power factorization with Fragmentation Functions (FFs) computed in nonrelativistic QCD and evolved to…
We present an uncertainty-aware description of leading-power fragmentation for all-charm pentaquark states ($S$-wave $|cccc\bar{c}\rangle$) at hadron colliders. We construct a multimodal set of collinear fragmentation functions, PQ5Q1.1,…
I discuss several theoretical tools which are useful for analyzing perturbative and non-perturbative problems in quantum chromodynamics, including (a) the light-cone Fock expansion, (b) the effective charge $\alpha_V$, (c) conformal…
Sufficiently inclusive observables in the decay of the tau lepton can be calculated using the methods of perturbative QCD. These include the asymmetry parameter $A_\tau$ that determines that angular distribution of the total hadron momentum…
An exploratory study for a new determination of the strong coupling constant alpha_s(MZ) from existing world data on the proton structure function F2p in the Q**2-range from ~ 5 to ~ 120 (GeV/c)**2 is presented. The main features of our…
High quality factor ($Q$) nanomechanical resonators have received a lot of attention for sensor applications with unprecedented sensitivity. Despite the large interest, few investigations into the frequency stability of high-$Q$ resonators…
A linear time-invariant dissipative Hamiltonian (DH) system x' = (J-R)Q x, with a skew-Hermitian J, an Hermitian positive semi-definite R, and an Hermitian positive definite Q, is always Lyapunov stable and under weak further conditions…
The angular distributions of lepton pairs in the Drell-Yan process can provide rich information on the underlying QCD production mechanisms. These dynamics can be parameterised in terms of a set of frame dependent angular coefficients,…
Infrared- and collinear-safe (IRC-safe) observables have finite cross sections to each fixed-order in perturbative QCD. Generically, ratios of IRC-safe observables are themselves not IRC safe and do not have a valid fixed-order expansion.…
The perturbative QCD expansion for $J/\psi$ photoproduction appears to be unstable: the NLO correction is large (and of opposite sign) to the LO contribution. Moreover, the predictions are very sensitive to the choice of factorization and…
In the asymptotic limit $Q^2 \gg m^2$, the heavy quark form factors exhibit Sudakov behavior. We study the corresponding renormalization group equations of the heavy quark form factors which do not only govern the structure of infrared…
We consider resonant production of sneutrino and slepton at hadronic colliders such as the Tevatron and the LHC within the context of a R-parity violating supersymmetric model. We present next to leading order QCD corrections to total cross…
QCD calculations for collider physics make use of perturbative solutions of renormalisation group equations (RGEs). Ambiguities related to these solutions can contribute significantly to systematic uncertainties of theoretical predictions…
In this paper we report calculations of the relativistic corrections to transition frequencies (q factors) of Yb II for the transitions from the odd-parity states to the metastable state $4f^{13}6s^2 ^2F_{7/2}^o$. These transitions are of…
We discuss the distinct approaches for high density QCD (hdQCD) in the asymptotic regime of large values of parton density. We derive the AGL equation for running coupling constant and obtain the asymptotic solution, demonstrating that the…
The perturbative non-linear (NL) effects in the small-$x$ evolution of the gluon densities depend crucially on the infrared (IR) regularization. The IR regulator, $R_c$, is determined by the scale of the non-perturbative fluctuations of QCD…
The longitudinal structure function in deep inelastic scattering is one of the observables from which the gluon distribution can be unfolded. Consequently, this observable can be used to constrain the QCD dynamics at small $x$. In this work…