The moments of the heavy quark-parton distribution functions in a heavy pseudoscalar meson, obtained in QCD sum rules, are expanded in the inverse heavy quark. Comparison with the finite mass results reveals that while the heavy mass expansion works reasonably well for the $b$ quark, one has to take into account terms of higher than $(1/m_c)^2$ order for the $c$ quark.
The discriminators of quark-gluon jets developed for $pp$ collisions at the LHC can be used to measure the gluon jet fraction in a jet sample. It allows to measure various characteristics of the quark and gluon jets. The methodology of such measurements for modern hadron colliders is discussed.
Unified Description of Hadrons and Heavy Hadron Decays
利用轻夸克的手征味对称性和重夸克的手征味对称性，构造了一个描述轻重强子相互作用的有效拉格朗日量。对于轻扇区和重扇区，我们在拉格朗日量中包含了赝标量、矢量和重子。作为我们形式的应用，讨论了重强子衰变。由$D^0 \rightarrow K^- e^+ν_e$衰变的实验数据拟合了$D_s$衰变常数和重介子、重矢量介子和轻介子之间的耦合常数。我们还指出了从$Λ_b \rightarrow p l \bar ν$衰变中独立测定$|V_{ub}|$的可能性。
The origin and main properties of new heavy hadrons as dark matter candidates, are represented. Low-energy interactions of new hadrons with leptons and nucleons are described in the terms of effective vertexes. We consider the lowest excited levels of new mesons in the frame-work of the Heavy Quark Effective Theory. The effect of fine and hyper-fine splitting of excited states follows directly from this theory. We analyze phenomenological consequences of this effect as manifestation of dark matter particles.
Heavy hadron spectroscopy was well understood within the naive quark model until the end of the past century. However, in 2003, the $X(3872)$ was discovered, with puzzling properties difficult to understand in the simple naive quark model picture. This state made clear that excited states of heavy mesons should be coupled to two-meson states in order to understand not only the masses but, in some cases, unexpected decay properties. In this work we will review how the naive quark model can be complemented with the coupling to two hadron thresholds. This program has been already applied to the h…
Most of the methods to measure the top quark mass suffer from the jet energy scaling in achieving better precision. As a way to circumvent this issue, the study of $B$-hadron observables is motivated. While they do not involve such an issue, understanding underlying hadronization models is a key to achieve $\sim 0.5\%$ precision or better. In this presentation, we discuss the impact of the hadronization model parameters - for example, implemented in Pythia 8 - on precision measurements of the top quark mass through $B$-hadron observables. We study the sensitivity of the top quark mass to relev…
Nucleus-nucleus collisions offer a great opportunity for analyzing and determining the intrinsic nature of heavy and exotic hadrons. In this sense, here we discuss how the production and dissociation of hadron states are affected by reactions during the expansion of hadronic matter in a heavy-ion collision environment. We give emphasis to recent works on exotic states, revisiting as a case study the time evolution of the abundances of the $X_{0,1}(2900)$ states.
